**Geotourism in the Cilento, Vallo di Diano and Alburni UNESCO Global Geopark (Southern Italy): The Middle Bussento Karst System**

### **Ettore Valente 1,\*, Antonio Santo 2, Domenico Guida <sup>3</sup> and Nicoletta Santangelo <sup>1</sup>**


Received: 27 March 2020; Accepted: 17 April 2020; Published: 26 April 2020

**Abstract:** In this paper we want to stress the role of geotourism as a means to promote environmental education and, on occasion, as a way to increase the touristic interest of an area. Geoparks are certainly the territory where geotourism can be best exploited. We propose a geoitinerary to discover the amazing, but poorly known, Middle Bussento Karst System, with the blind valley of the Bussento River, in the southeast of the Cilento, Vallo di Diano and Alburni United Nations Educational, Scientific and Cultural Organization (UNESCO) Global Geopark. This is the only example, in Southern Italy, of a stream sinking underground and it is the second longest subsurface river path in Italy, making this a core area of the Geopark. We combined field surveys and literature data to create a geoitinerary that can be useful in helping to promote this site. This geoitinerary is applicable to both simple generic visitors and geo-tourists and has an educational purpose, especially in explaining the significance and the fragility of karst areas in terms of environmental protection. Moreover, it may represent a sort of stimulus for the growth of touristic activity in this inner area of the Geopark.

**Keywords:** geotourism; geomorphosites; environmental education; Cilento, Vallo di Diano and Alburni Geopark; Middle Bussento Karst System

#### **1. Introduction**

### *1.1. Geoparks and Geotourism: An Overview*

In recent decades, the growing awareness to protect nature from human impact has led to the diffusion of several legislative and social actions, both at international and national levels. The protection of nature is, for example, clearly expressed in article no. 9 of the Italian Constitution [1], from December 1947. In Italy, one of the first laws to address the protection of nature is the Galasso Law (law no. 431, 22 August 1985). This law introduced the concept of "protected areas" in Italian territory, namely seas, rivers, mountain areas from 1200 m above sea level (m a.s.l.), volcanoes, forests, glaciers, national parks, and archaeological areas.

At the international level, in 1972, the United Nations Educational, Scientific and Cultural Organization (UNESCO) adopted the convention "Concerning the Protection of the World Cultural and Natural Heritage". This convention identified 1500 sites all over the world to be included in the World Heritage List, due to outstanding values of their natural and cultural features ([2,3] and references therein). Currently, the sites included in the World Heritage List are mainly cultural sites (869 of the 1121 sites), whereas a lower number of natural sites with a high geological and geomorphological scientific and scenic value are included in the list (213 of the 1121 sites; [4]). To overpass this low number of natural sites included in the World Heritage List and considering the large number of sites in the world with high geo-scientific significance, in 1997 the Division of Earth Science at UNESCO proposed a new program called the "UNESCO's Geoparks Programme" [5,6]. Prior to the creation of this program, the idea of establishing a Geoparks network was settled for the first time during the 30th International Geological Congress in Beijing in 1996 [6]. A Geopark is defined as "a territory with well-defined limits that has a large enough surface area for it to serve local economic development. The Geopark comprises a number of geological-paleontological heritage sites of special scientific importance, rarity or beauty; it may not be solely of geological-paleontological significance but also of archaeological, ecological, historical or cultural value" [2]. The first 25 Geoparks were established in Europe and China, and in 2004 they formed the UNESCO Global Geoparks Network [2,6]. It is worth mentioning that the first protected area in the world was established at Yellowstone National Park in North America in 1872 [7]. Currently, only three Canadian national parks have gained the title of 'Geoparks' in North America [8]. UNESCO Global Geoparks are defined as "single, unified geographical areas where sites and landscapes of international geological significance are managed with a holistic concept of protection, education and sustainable development" [9]. UNESCO Global Geoparks focus their activities on raising awareness in the local community about the geological heritage of the area, promoting the concept that the landscape is a dynamic element, stimulating sustainable Geotourism, and encouraging the protection of geological resources [9].

The definition of Geopark includes a clear reference to local economic development, so geological and geomorphological features within a Geopark must be considered as crucial geological resources ([10] and references therein) forming the so-called geoheritage [11–13]. Growth of the local economy must be practiced through sustainable management strategies that seek to develop geotourism by attracting an increasing number of visitors. The concept of geotourism has widely diffused in the last decades [14–19] among international papers covering many countries throughout the world ([20] and references therein). Moreover, Dowling and Newsome [21] highlighted that geotourism can be defined from both a geological and a geographical point of view. The geological definition of geotourism was first proposed by Hose [14,22] who defined it as "the provision of interpretive and service facilities to enable tourists to acquire knowledge and understanding of the geology and geomorphology of a site beyond the level of a mere aesthetic appreciation". This definition has since been refined by the same author [23,24]. In 2006 another definition was proposed by Dowling and Newsome [16] who introduced the concept of scale, suggesting that geotourism focuses on both small geological and paleontological sites and large landforms and landscapes. Newsome and Dowling [17] pointed out that geotourism is a form of tourism focused on geology and landscape that can be carried out either by independent visits or guided tours. Hose [15] suggested that geotourism is underpinned by the so-called 3G's, namely geoconservation, geohistory, and geo-interpretation. In contrast, in 2000, the National Geographic Society of the United States of America defined geotourism as "tourism that sustains or enhances the geographical character of a place-its environment, culture, aesthetics, heritage, and the well-being of its residents" ([21] and references therein). In 2006 a new definition was set by Pralong [25] that highlighted the emotional aspects of geotourism and introduced the concept of geomarketing, thus placing geotourism as a component of the regional economy. Subsequently, in 2011, during the International Congress on Geotourism at Arouca (Portugal) a new definition was proposed that included the term "geology" in the geographical definition of geotourism [26]. These two points of view on what is geotourism suggest considering it either as a "type or form" of tourism (geological definition) or as an "approach" to tourism (geographical definition) [21]. In this paper we adopt the geological definition of geotourism.

To discuss geoheritage and geotourism it is necessary to recognize geosites and geomorphosites. The former are "portions of the geosphere that present a particular importance for the comprehension

and reconstruction of the history of the Earth, climate and life" [27]. The latter are "geomorphological landforms that have acquired a scientific, cultural/historical, aesthetic and/or social/economic value due to human perception or exploitation" [28]. Moreover, the assessment methods of geomorphosites and their importance in geotourism and geoheritage have been widely discussed in international papers [29–45].

The concept of geotourism has been widely diffused in Italy. With its ten UNESCO Geoparks, is the third country in the world with the highest number of Geoparks, being preceded only by China and Spain [8]. Addressing Geotourism and Earth Science education in Italy, numerous scientific papers have been produced which deal with geosites and geomorphosites inventory in many areas of the national territory [46–53]. Most of these papers focus on Central and Northern Italy, and less international papers have been published which deal with geosites and geotourism in Southern Italy [54–58]. In particular, few international papers [59] and conference proceedings [60] have addressed Cilento, Vallo di Diano and Alburni Geopark and only some national papers [61–63] deal with geosites inventory and geotourism in the territory of the Geopark.

#### *1.2. The Cilento, Vallo di Diano and Alburni UNESCO Global Geopark*

The Cilento, Vallo di Diano and Alburni Geopark (Figure 1) is among the largest Italian Geoparks, covering an area of 181,048 ha that includes 80 municipalities in the province of Salerno, with a population of ~280,000 inhabitants. The Geopark was firstly established as a national park, namely the National Park of Cilento and Vallo di Diano, in 1991 under the law 394/91. In 1997 the national park was included in the Man and the Biosphere Program of UNESCO and it became part of UNESCO's World Heritage List in 1998. Then in 2010 during the 9th European Conference of Geoparks in Lesvos (Greece), it gained the title of Geopark and became part of the European Geopark Network. The Geopark finally gained the title of UNESCO Global Geopark in 2015.

**Figure 1.** Geological map of the Southern Apennines (modified from [64]). Thick black line indicates the boundary of the Cilento, Vallo di Diano and Alburni Geopark (from [65]). White box in the southest (SE) corner of the Geopark indicates the location of Figure 2.

The Geopark of Cilento, Vallo di Diano and Alburni is located in the southern part of the Campania region. It extends from the coastal areas between the towns of Agropoli, to the north, and Sapri, to the south, up to the mountain ridges of the Southern Apennines chain, towards the east, reaching a maximum elevation of 1898 m above sea level (m a.s.l.) at the peak of Mt. Cervati (Figure 1). The Geopark is characterized by a complex geological setting, with large outcrops of permeable carbonate units in the inner mountainous landscape and less permeable or even impermeable wedge-top and basinal units towards the coast (Figure 1). Its complex geological setting results in a large variety of stratigraphical and geomorphological features, whose scientific importance and beautiful scenery are undisputed [59]. While the coastal area with its beautiful beaches and the well-known archeological sites of Paestum and Velia (Figure 1) is a continuously growing touristic attraction, with thousands of visitors per year, the inner portion of the park is less visited and there are few initiatives promoted to invert this trend.

Inventory, evaluation, and protection of the wide geological estate of the Geopark have been carried out by the competent authorities and are listed in the official catalogue promoted by national [66] and regional institutions [67], as well as by the Geopark itself. Moreover, Santangelo et al. [59] identified a total of 263 sites of geological interest, 32% of which are geomorphosites.

In this paper, we investigate a poorly known portion of the Geopark that is placed along its southeastern border. This portion of the Geopark is mainly made up of Mesozoic carbonate platform successions (Figure 1) which are strongly karstified and host some of the most important water reservoirs of the region with springs that have a total discharge of more than 20 m3/s [68,69]. Karst processes are so well represented in the area both at the surface (doline, polje, gorges, ponors, karst springs) and underground (horizontal and vertical cave/karst systems [70]). Many of these karst landforms are listed in the official catalogue of the Geopark [71] as geomorphosites according to different perspectives: some cave, for instance, preserve important archaeological records [72], while others represent the longest or the deepest karst systems of the area; meanwhile others are exemplary or have a particular didactic value [59].

Unfortunately, up until now, few initiatives have been carried out to promote this significant geological estate. The foundation of the Musei Integrati dell'Ambiente (MIDA) museum [73], which is part of the touristic Pertosa cave management system (see Figure 1 for location), has, among others, a sector dedicated to the explanation of karst processes. At the same time, the proposition of geotouristic itineraries in this portion of the Geopark is still at an early stage with only some papers addressed to both Italian (itineraries n. 11, 12, and 13 in [61–63]) and international tourists [54]. Moreover, Aloia and colleagues [61] briefly discuss the importance of correct management strategies of the Geopark as a tool to direct touristic flows from the coastal area to the inner, hilly and mountainous areas.

Our study aims to focus attention on the karst geomorphosite of the middle Bussento river system. This site is the only example of stream sinking underground in Southern Italy [59] and is the second longest underground river in Italy, being preceded only by the Timavo River in North-East Italy [74]. This geomorphosite includes a system of ponors, the largest of which is the La Rupe ponor, where the Bussento River sinks, and the Bussento Resurgence, where the Bussento River reemerges after a ~4 km long subsurface path. The area is already the object of some, local scale, touristic promotion activities such as the foundation of the Museo Virtuale (MU.VI.), a virtual museum conceived as an educational and scientific center, managed by the Caselle in Pittari administration, where teaching materials are organized for presentation by means of visual technologies (multi-touch screen, 3D room for virtual reconstruction). Yet despite the high scientific and educational values of this portion of the Bussento river valley, an adequate, comprehensive geotourism policy has not been assessed by the local administration.

In this context, we attempt to contribute to an increase in the knowledge of this fascinating portion of the Geopark by the promotion of a comprehensive geoitinerary, which should serve both as a scientific and educational instrument at inter-municipality scale. The main aims of this work are: (i) contributing to explain how karst processes can make a river disappear underground; (ii) discussing the importance of karst aquifer and the main environmental implications connected to the communication between surface and underground waters; (iii) increasing curiosity about this site, helping to promote the integrate management of this inner portion of the Geopark as a touristic attraction and thus helping to grow the local and the district economy.

**Figure 2.** Geological map of the Middle Bussento Karst System (modified from [75]).

#### **2. Study Area: The Middle Bussento Karst System**

The study area is characterized by the occurrence, in a very restricted area, of Jurassic to Eocene carbonate units, of Eocene to Miocene internal units, and of Miocene flysch and Cilento units (Figure 2). Carbonate units consist of inner platform limestone with high fossils content (rudists and gasteropods) passing upward to open shelf limestone with interlayered marls and clays. Internal units consist of clays with interbedded quartz-rich and feldspar-rich sandstones passing upwards through calcilutite, calcarenite, and calcirudite with cherty lists and nodules and with interbedded quartz-arenite and marls strata. Miocene flysch units consist of a fining-upward sequence of thrust-top deposits whereas the Miocene Cilento group consists of a coarsening upward sequence of a wedge-top basin [75].

The actual structural setting of the area derives from its complex tectonic evolution with internal units thrusted over the carbonate units that were covered by the flysch units. The tectonic setting is completed by the occurrence of E-W, NW-SE, and NW-SE normal faults that articulate the topography. Moreover, flysch units have been eroded from the high carbonate peaks and are preserved only along the main valleys [75]. The complex tectonic evolution of the area is discussed in other studies [76–82].

The main river flowing in the study area is the Bussento River (Figure 2). This river originates from Mt. Cervati and Mt. Ficarola, following a mainly NW-SE orientation in the upper portion of its basin where it carves impermeable units. At the base of Mt. L'Alta (Figure 2) the Bussento River flows along a N-S trend and starts carving into the Mesozoic carbonate units. Then, it suddenly disappears near the village of Caselle in Pittari in the so called La Rupe ponor to flow out again ~4 km to the south, in the so-called Bussento Resurgence, near the village of Morigerati (Figure 2). To the east of the middle Bussento River there are two more rivers—Orsivacca River and Rio della Bacuta River—that, after flowing in the impermeable flysch and internal units, suddenly disappear underground when

they carve the carbonate units. Moreover, the Orsivacca River ends in the Orsivacca ponor whereas the Rio della Bacuta River has both a fossil and an active ponor, respectively named the Cozzetta and Bacuta ponors (Figure 2). D'Elia et al. [83] suggested that the Orsivacca and the Rio della Bacuta rivers were left tributaries of the Bussento River and that they were separated from it following the ponor regression mechanism [84,85]. The separation of the Orsivacca and the Rio della Bacuta rivers from the Bussento River is also testified by a paleo-valley placed in-between the relative ponors. When these three river segments were connected, the Bussento River should have had a higher discharge that could justify the presence of a large fossil ponor, named the Bussento paleo-ponor (Figure 2), which is placed to the southwest of the active La Rupe ponor [83].

It is worth noting that the Bussento River is intercepted by the Sabetta reservoir, an artificial basin created in 1958, which serves a hydroelectrical powerplant. Therefore, the Bussento River discharge downstream of the Sabetta reservoir depends on the amount of water released for operational activities and the amount of water coming from the residual drainage basin between the Sabetta Lake and the La Rupe ponor [86].

Regarding the hydrogeological setting of the area, the main aquifer is part of the carbonate structure of the Salice-Coccovello Mts, which drains towards the basal spring systems of Morigerati, located at about 90 m a.s.l., which has a total discharge of 1.5 m3/s. Hydrogeological analysis has proved a subsurface connection between the La Rupe, Orsivacca, Cozzetta, and Bacuta ponors with the Morigerati springs, that are all part of the so-called Middle Bussento Karst System [87].

Recent scientific interdisciplinary research has studied the Middle Bussento Karst System as one of the most interesting karst systems in Southern Italy, spanning from the singular karst back-flooding to the karst pulse floods, suggesting it as experimental UNESCO karst basin [86] for geodiversity conservation, protection, and promotion.

#### **3. Materials and Methods**

As we already discussed in Section 1, Geoparks are intended to not only protect the geoheritage of an area but also to promote a holistic concept of education and sustainable development. Within a Geopark, geotourism represents the most useful tool to enable tourists to acquire knowledge and understanding of the geology and geomorphology of a site. With these concepts in mind, we focused our attention on the inner area of the Cilento, Alburni and Vallo di Diano Geopark, and chose one of the geosites already listed in the official catalogue by the competent authorities. We used this site as an example of how geotourism may be a useful tool to increase the touristic attraction of an area and promote environmental education.

The inner part of the Geopark is mainly made of carbonate rocks and for this reason our choice fell among karstic geomorphosites. We selected the Middle Bussento Karst System because of its uniqueness as the sole example of an underground river in Southern Italy. Moreover, it also has a high didactic value because it is representative of the extreme significance and sensitivity of the karst environment as water reservoirs.

We collected and revised all literature data about the geological, geomorphological, hydrogeological, and speleological setting of the Middle Bussento Karst System and planned the geoitinerary.

Field surveys (5 days in total) were carried out to detail the technical issues of the geoitinerary. It is 17 km long and can be done entirely by walking or it is possible to move by car from one stop to the next. For those who prefer the latter option, we determined the path length for each stop. It indicates the distance from the place where tourists can leave the car until they reach the ponor. In addition, the duration (in hours) of both the entire geoitinerary and every single path is indicated, together with the differences in elevation of every path and the main geological and geomorphological features that can be admired along each path.

To emphasize the scientific and educational importance of the proposed itinerary we prepared some sketches to provide tourists with a complete overview of both the surface and subsurface setting of the Middle Bussento Karst System. These sketches include a 10 m digital terrain model (DTM) of the investigated area and a 3D view of the topography (both from the south and from the east). The 10 m DTM was created from elevation data (both contour lines and elevation points) derived from a detailed scale topographic map (Technical Map of the Campania Region, at scale 1:5000). Elevation data were imported in a Geographic Information System (GIS) software (ArcGis 10.7©, Redlands, CA, USA) and interpolated by means of the Topo to Raster tool to obtain the DTM that, successively, was used to derive the hillshade map (by means of the 3D Analyst tool in ArcGis) and the river network (by means of the Hydrology tool in ArcGis). Both the hillshade map and the river network were then imported in the ArcScene module of ArcGis to obtain two 3D views of the topography that focused on the area between the Sabetta Lake, to the north, and the Bussento Resurgence, to the south. These two 3D views, respectively from the south and from the west, were then imported in Corel Draw© (Ottawa, MI, Canada) to produce the final sketch.

To analyze the potential of the proposed geoitinerary, we carried out a classical SWOT (strengths, weaknesses, opportunities and threats) analysis. Finally, to assess the geotouristic value of the Middle Bussento Karst System geomorphosite, we calculated the index proposed by Pica et al. [88] named the value of a site for geotourism (VSG). It results from the following equation:

$$\text{VSG} = \text{RP} + \text{RR} + \text{SCE} + \text{SAC} + \text{AC} \tag{1}$$

RP is the representativeness index, RR is the rarity index, SCE is the scenic-aesthetic value, SAC is the historical-archaeological-cultural value, and AC is the accessibility index. Each index has a maximum score of 5 so that the highest value of the VSG is 25. The scores derive from the geosites' characteristics reported in Table 1. According to Pica et al. [88], VSG values lower than 8 indicate that the site has low touristic potential, VSG values between 9 and 16 indicate a medium touristic potential, and values between 17 and 25 indicate a high touristic potential.

**Table 1.** Scores of the indexes used for the evaluation of the value of a site for geotourism (VSG) index (from Pica et al. [88]). RP = representativeness index; RR = rarity index; SCE = scenic-aesthetic value; SAC = historical-archaeological-cultural value; AC = accessibility index.



**Table 1.** *Cont*.

#### **4. Results**

*4.1. Karst Landforms (Ponors, Blind Valleys, Resurgences, and Karst Springs): Importance for Environmental Education*

Karst processes occur on Earth's surface in any place where soluble rocks like limestones or gypsum crop out and are exposed to the action of meteoric waters. The latter have a natural content of CO2 that increases during percolation in the soil. For this reason, they can dissolve soluble rocks, creating spectacular morphologies both at the surface and underground [89] (Figure 3). Dissolution makes the rocks highly permeable, allowing for the circulation and accumulation of water underground. A mountain made up of permeable and soluble rock, like limestone, behaves as a sponge, adsorbing all the meteoric waters dropping above its surface. For this reason, at depth, a subterranean water body originates, called by geologists as a "water table". The mountain containing this water body is called "aquifer". Karst water aquifers represent the most important water reservoirs on our planet, furnishing a high percentage of the drinkable water feeding our aqueducts [90].

Karst processes are governed by the following simple chemical equation:

$$\text{CaCO}\_3 + \text{CO}\_2 + \text{H}\_2\text{O} \leftrightarrow \text{Ca(HCO}\_3)\_2\tag{2}$$

In this work, we describe some peculiar karst morphologies that originate when a karst system is fed not only by meteoric waters (autogenic karst), but also by runoff waters coming from a non-karst area (allogenic karst; [86]). This phenomenon is possible when limestone successions crop out in association with other less permeable or impermeable rocks. During meteoric events, the running waters collect on impermeable rocks and create a drainage network that flows on the surface until it meets soluble rocks. At this point, water may attack the more fractured rocks by chemical dissolution where it starts to create a concentrate infiltration point, the so-called ponor. Thus, what are ponors? They are simply holes on the Earth's surface where streams disappear underground. They are also called swallow holes or stream-sinks. The stream waters, during geological time, are able to "dig" these holes in the carbonate rocks because they are soluble and susceptible to karst processes. This kind

of ponor, located at the contact between permeable and impermeable rocks, is referred to by geologists as a "contact ponor" (Figure 4; [70]). The largest is the upstream valley, and the biggest will be the hole that the water may dig in the carbonate rocks. The drainage basin located upstream of a ponor is called the "blind valley" because it has no continuation on the surface, but it disappears underground. In association with ponors there are always cave systems (Figure 5A) that, depending on the difference in altitude between the ponor and the basal water table, may transfer the surface water towards a resurgence or may directly feed the water table (Figure 5B). This condition makes karst aquifers highly vulnerable regarding possible contamination between surface waters and underground waters [91]. Anything spilled anywhere in the catchment of a blind valley may directly reach an underground water table, even if it is very far from the spilling point.

**Figure 3.** Examples of epikarst and endokarst morphologies in the Cilento, Vallo di Diano and Alburni Geopark: (**A**) karren; (**B**) doline at the summit of the Mt. Cervati peak; (**C**) carbonate concretion, stalactites, in a cave.

**Figure 4.** A 3D sketch (**A**) showing the formation of contact ponor and (**B**) cross-section view showing the communication between the stream waters sinking in the ponor and the basal water table.

**Figure 5.** (**A**,**B**) Internal views of karst systems associated with ponors (Cilento, Vallo di Diano and Alburni Geopark).

In the southern Apennines, the main springs that are intercepted for drinkable use are placed at the base of the carbonate massifs, with single discharge that often exceeds 2000–3000 L/s [68,92]. Most of these water resources are fed by the karst system for which a communication between ponor at the surface and subsurface water table has been proven [93]. Amazing examples of these features are the endoreic karst basin of the Matese Massif and the Picentini Mts. [64,93,94] and the carbonate slopes of the Cilento, Vallo di Diano and Alburni Geopark [70,95]. In some cases, the contamination of the water sinking in the ponor has been proven [95,96]. This is what makes karst areas, where stream sinks and blind valleys are present, extremely sensitive environments, where surface waters may come directly in contact with underground water reservoirs. All human activities insisting on a drainage basin located upstream of a ponor must take into account the possibility of interfering with the basal water table. These simple concepts on how a karst aquifer functions should be basic components in the environmental education of every citizen and administrator. Geotourism offers the possibility of coming directly in contact with these problems, not only by studying but also in such activities as taking a walk. Therefore, we propose a geoitinerary in the area of the middle Bussento River system since it is a good case to understand this karst environment.

#### *4.2. The Karst Ponors and the Blind Valley of the Bussento River: Proposed Geoitinerary*

In the middle Bussento river valley karst processes are well developed and mostly represented by contact ponors with associated cave systems and blind valleys. The Bussento River originated from Mt. Cervati and Mt. Figarola (Figures 1 and 2). Its drainage basin is carved on impermeable and soft rocks belonging to Miocene flysch deposits (Cilento group) and to Eocene-Miocene clayey basinal successions (internal units). The river flows for about 10 km in a N-S direction on this soft rock then it reaches the northern slope of the carbonate ridge of Mt. Pannello and abruptly disappears, sinking into a big hole called the La Rupe ponor (Figure 6).

**Figure 6.** Google Earth image of the La Rupe ponor area. Arrows indicate flow direction. Red line indicates the La Rupe ponor. White points are elevation points.

The proposed geoitinerary is shown in Figure 7, whereas its technical issues are reported in Table 2.



**Figure 7.** Upper panel: proposed geoitinerary in the discover of the Middle Bussento Karst System (yellow line). Stars indicate geoitinerary stops. S1: La Rupe ponor; S2: Orsivacca ponor; S3: Rio della Bacuta valley with its active (Bacuta) and fossil (Cozzetta) ponors; S4: MU. VI.; S5: Bussento Resurgence. See Figure 2 for legend of the geological units. Lower panel: 3D view, from west, of the area between the Bussento River, the Orsivacca River, and the Rio della Bacuta River. Red points are ponors. Blue lines indicate the river network and arrows indicate the flow direction. White points are elevation points.

The map and the 3D model of Figure 7 show that two little streams occur to the left of the Bussento River, named the Rio della Bacuta River and the Orsivacca River, which disappear underground and may be classified as blind valleys. Their drainage basins upstream of the ponors are carved into soft rocks and the streams disappear when they meet the carbonate rocks.

The starting point of the path that bring tourists to stop no. 1, the La Rupe ponor (Figure 8A), is 3 km far from the urban area of Caselle in Pittari and it is near a gentle surface placed at the foot of the northern slope of Mt. Pannello. During the drop towards the La Rupe ponor, tourists may admire the stratified carbonate bedrock with several small-scale epikarst features (e.g., dissolution pans, karren). Tourists will reach the Bussento River valley bottom after having travelled for 900 m. The water level is very low because it is regulated by the Sabetta Lake hydroelectric powerplant placed about 2.5 km upstream of the Bussento ponor. Before the dam construction in 1958, the river waters entered the ponor with a higher flow rate, carrying out a significant debris load, as indicated by the large (cubic decimeters to cubic meters), rounded to sub-rounded boulders covering the valley floor. During extreme floods, this material obstructed the entrance of the ponor causing the formation of a wide lake. Local inhabitants called this phenomenon "Votamare" or "Ultimare", which means the area looked like the sea. After a 100 m walk along the Bussento River valley floor, tourists will reach the La Rupe ponor. The entrance, which is about 30 m high and 10 m large, is very spectacular and represents the point where the Bussento river starts to flow underground (Figure 8B,C). During geological time the river waters created an underground channel, at least 4 km long, that cut across the Mt. Pannello ridge and resurged at the surface at the foot of its southern slope, near the village of Morigerati, in the so-called Bussento Resurgence (Figure 7). Only tourists with either a speleological background or under the guide of an expert speleologist may visit the initial part of this underground channel, which is explored for only 566 m. It develops mainly following SW-NE and NW-SE trends and ends in a siphon lake.

From the La Rupe ponor, tourists will return to the main road to reach the Orsivacca, Cozzetta, and Bacuta ponors (stops S2 and S3 in Figure 7). The Orsivacca valley floor is dry for most of the year but during autumn and winter seasons it is possible to admire the water falling within the ponor. As shown in Figure 9, the ponor's dimensions are very little in respect to those of "La Rupe", being smaller their catchments. These ponors are in connection with caves and, in these cases, only persons with a good speleological background and under the guide of an expert speleologist have access.

After visiting the Rio della Bacuta and Orsivacca blind valleys, tourists will return to the main road to reach the fourth stop of the geoitinerary, the MU.VI. (Museo Virtuale, "Virtual Museum", stop S4 in Figure 7). The MU.VI. is a building (Figure 10) where it is possible to admire a permanent virtual exhibition about the Middle Bussento Karst System under the guide of experts either from local associations addressed to the promotion of the territory or from speleologists of the Italian Alpine Club (a speleological group). The visit to the MU.VI. is 1 h long and here it is possible to organize other outdoor activities (e.g., trekking, canyoning, pedal cars, mountain biking) that are not included in the proposed itinerary, but that can be provided by local associations. In addition, for those that enjoy outdoor activities, there is an area where it is possible to practice fitness exercises right in front of the MU.VI. entrance.

Tourists will then move from the MU.VI. towards the last stop of the geoitinerary, the Bussento Resurgence (stop S5 in Figure 7), which is 6.5 km away and can be reached by car (15 min) or by walking (~1 h).

**Figure 8.** Stop no. 1: La Rupe ponor. (**A**) Panoramic view of the Bussento River valley and the entrance of the La Rupe ponor; (**B**) the La Rupe ponor entrance; (**C**) close view of the La Rupe ponor entrance.

**Figure 9.** (**A**) Stop no. 2: the Orsivacca ponor; (**B**) the fossil Cozzetta ponor; (**C**) the active Bacuta ponor.

**Figure 10.** (**A**) Stop no. 4: the entrance of the MU. VI. (virtual museum); (**B**) lateral view of the MU.VI. with the eastern slope of Mt. San Michele in the background.

This stop visits both the Old Mill springs and the Bussento River resurgence. Along the drop towards the valley floor, tourists can admire amazing rudists fossils (Figure 11A) in the carbonate bedrock. A small railway is also present to facilitate the tour either for tourists not used to trekking or for people that do not want to become tired. Once tourists reach the valley floor, they may admire the amazing Old Mill spring (Figure 11B) which is one of the basal springs of the Salice-Coccovello carbonate aquifer. This spring has a mean discharge of 50 L/s. Then, walking along a woody path next to the water level, they may reach the Bussento Resurgence, the point where the Bussento River rises again to the surface. The cave system associated with the resurgence (Figure 11C) is mostly horizontal and expert speleologists explore it for 462 m. Hydrogeological analysis (tracing tests) has proved a subsurface connection between the La Rupe, Orsivacca, Cozzetta, and Bacuta ponors with the Bussento Resurgence, as explained in Figure 12. The waters sinking in these ponors connect and travel underground at least for 4 km, making this case the only example of an underground river in

Southern Italy. Considering the ponors and the resurgence altitude in respect of the water table level, it is possible to understand that there is the possibility that the stream waters during their underground path may feed the basal water table (see blue arrows in Figure 12).

**Figure 11.** Stop no. 5: the Bussento Risurgence near Morigerati. (**A**) Detail of rudists fossils in the carbonatic bedrock; (**B**) the Old Mill spring; (**C**) the visiting tour in the interior of the Morigerati Resurgence; (**D**) view, from the inner side of the Bussento Resurgence, of the steep valley flanks.

The Bussento Resurgence, in addition to being an important geomorphosite, it is also a World Wildlife Foundation (WWF) Oasis, with an educational and international center, where it is possible to gain information about both the abiotic and biotic components of the environment.

Moreover, from the resurgence down-valley, the Bussento River created a gorge (Figure 11D), another peculiar karst morphology. Gorges are formed when a river flows on karst carbonate rocks and tends to dissolve them, leading to the formation of deep and narrow valleys, which often host a natural habitat of high environmental quality. Gorge flanks are high and very steep, making the gorges inaccessible areas except for expert speleologists or for those practicing canyoning.

**Figure 12.** Frontal (from south, upper panel) and lateral (from east, lower panel) 3D views of the Middle Bussento Karst System. Red lines indicate the explored subsurface portion of the karst system (from [98]). White triangles in the upper panel are elevation points (expressed in meters above sea level).

#### **5. Discussion**

#### *5.1. Geotourism in Karst Area*

Karst terrains are widespread all over the world and cover about 17% of the Earth's surface [99], a percentage that increased up to 21.6% in Europe [100]. These data highlight the importance of karst terrains and landforms as crucial geological and geomorphological features to promote geotourism; in particular considering that 37% of Geoparks in the world exhibit karst phenomenon [101]. Ruban ([101] and references therein) highlighted the main features that make karst area prone to geotourism. According to Ruban, karst areas are, in fact, either unusual and rare landforms or windows into the dynamic geological environment: they attracted tourists before the actual concept of geotourism developed; they have aesthetic attractiveness; they are strongly related to the archaeological, historical, and ethnocultural peculiarities of some areas; they are of socio-economic importance because they are the main water reservoirs. Among karst landforms, the ones that play a major role in attracting tourists are caves [102]. Kim et al. [103] highlighted that cave tourism within geotourism gained large

popularity in Korea. Accordingly, Calaforra and Cortes [99] strengthened the importance of karst caves in geotourism as an instrument to favor local economic growth, indicating that karst caves in Spain receive more than 2.5 million visitors per year, with an economic return for the related municipalities (which often have less than 5000 inhabitants) in excess of 15 million euros [104]. Doorne [105] also highlighted the importance of karst caves in the local economy by discussing the Waitomo Glowworm Cave in New Zealand which serves a village of 500 inhabitants with a tourist population of around 450,000 international visitors per year. Allan et al. [106] focused on the motivations that lead tourists to visit places of geological importance by providing a questionnaire to tourists that visited the Cristal Cave in Australia. They found that the motivations of the visit include relaxation, escape from daily routine, sense of wonder, and knowledge. Hurtado et al. [107] also investigated Cristal Cave tourist traffic. Kiernar [108] discussed nature protection and geotourism in Laos where several karst caves receive tourist traffic related to religious motivation.

It is important that tourist traffic in karst caves avoid alteration of the natural environment, as proven for the Cave of Marvels in Spain [109]. Moreover, Baker and Genty [110] highlighted that tourist traffic in karst caves where ventilation is poor may alter CO2 concentrations and increase temperatures by 3◦. Calaforra et al. [111] carried out experimental measurements of caves' temperature at the Cueva del Agua de Iznalloz, Granada, Spain before the cave was opened to tourists, to determine the impact of human presence within the cave. Eagles et al. [112] pointed out that good planning and appropriate practices can lead to sustainable management of tourism.

Williams [113] stressed the importance of preserving the integrity of karst areas as a mandatory task because karst systems are complex systems that develop both at the surface and subsurface. Moreover, karst environments are an example of a fragile ecosystem whose balance depends on several factors such as the energy and quality of water flow. Williams [113] also remarked that environmental conditions in the recharge areas, both in allogenic and autogenic karst systems, have a strong influence on environmental conditions in the subsurface, thus suggesting that correct management of these areas is mandatory to avoid pollution in karst caves with dramatic consequences for plant and animals living in there. The previous point is fundamental considering that surface and subsurface water divides do not necessarily correspond, thus, karst drainage areas are not easy to delimit. The problem of preserving the integrity of a karst area is relevant also in the Middle Bussento Karst System. In fact, the Bussento River suffers both from low discharge due to the activity of the Sabetta Lake hydroelectrical powerplant and the organic pollution. This could cause severe problem to the 43 species found during speleological exploration at the La Rupe ponor [114,115]. Fortunately, subsurface water auto-depuration, due to a still poorly known subsurface karst path, dilutes the organic contaminants, making the water flowing out at the Bussento Resurgence in Morigerati the cleanest and able to host many fluvial organisms [114].

For what we have discussed up to now, it is evident that for geotourism in karst areas there is a fundamental task to diffuse the concept of environmental protection in these fragile ecosystems. The geoitinerary we propose intends to make people aware about the importance of karst areas as the main source for drinkable water by the combination of outdoor (trekking), indoor (speleological exploration under the guide of expert speleologists), and educational (visit to the MU.VI.) activities. It should also serve as a promoter of the territory by increasing curiosity about this poorly known portion of the Geopark and thus contributing to local economic growth.

#### *5.2. Promoting Geotourism in the Middle Bussento Karst System: What Has Been Done and What Can Be Done*

The scientific and educational values of the Middle Bussento Karst System are well known since the first exploration of the La Rupe ponor in the early 1950s [116]. Explorations were carried out in a discontinuous way until 2007 when speleologists from the Italian Alpine Club, section of Naples, reached the farthest point of the subsurface path [116]. Due to the high scientific value of the area, the Speleological Group of the Italian Alpine Club, section of Naples, in combination with other speleological groups from the Campania Region, organized the 2nd Regional Conference on Speleology in Caselle in Pittari, from 3–6 June 2010 [117]. This conference has been, up to now, the most important

scientific event during which the Middle Bussento Karst System has been at the center of discussions of hundreds of researchers and persons interested in speleology coming from all over Italy. During this conference, an intense educational activity was carried out at the MU.VI. by speleologists of the Campania Speleological Federation and the Speleological Group of the Italian Alpine Club, section of Naples [118].

Since then, educational activities geared towards knowledge and promotion of the territory have been carried out in a discontinuous way by local administrations and associations. These activities include outdoor sports such as canyoning, trekking, mountain biking, and pedal cars mainly concentrated during the spring and summer. In addition, local associations carry out environmental education activities in elementary, middle, and high schools in the surroundings of Caselle in Pittari. This often includes a visit of scholars to the MU.VI., where a permanent virtual exhibition on karst is present the entire year.

Further activities addressed to discover the Middle Bussento Karst System include personal initiatives by environmental guides often coming from areas outside the Geopark. These activities include a one-day trek to visit either the La Rupe ponor or the Bussento Resurgence. They usually do not include a one-night stay in the area to enjoy the hospitality of the locals and the amazing local food; thus, they do not contribute significantly in the growth of the local economy.

In our opinion, what is done to promote the territory, help the growth of the local economy, and emphasize the unicity of the Middle Bussento Karst System is good, but it is not enough. We must always have in mind that the Bussento River is the second longest subsurface path in Italy and this point should be a crucial promoting element to bring visitors to this area. The sporadic initiatives carried out either by local administrations and associations or environmental guides enhance the lack of coordination between these groups that, together, could do a lot for the local community. There is also a scarce amount of information on the Internet. For example, the local administration created a website to promote the area [119] but the amount of data available on the Internet about the Middle Bussento Karst System is sharply lower compared to other karst systems in the same Geopark (e.g., the Pertosa and Castelcivita caves).

We think that more convincing advertising actions are necessary if local administrations really want to help in the growth of local economy by attracting more tourists. The proposed geoitinerary emphasizes the fascinating subsurface world that characterizes the area, and tries to increase awareness among tourists, local people, and local administrations about the importance of karst areas as resources of potable water. In addition, the geoitinerary must be accompanied by a more effective and pervasive presence on the Internet through social media, and the production of attractive educational material that could make the Middle Bussento Karst System easily understood by non-geologists. An example could be the 3D reconstruction in Figure 12 that aims to describe the karst system in a simple way, helping tourists figure out the connection between the La Rupe, Orsivacca, Cozzetta, and Bacuta ponors and the Bussento Resurgence.

#### *5.3. SWOT Analysis and VSG Index*

To analyze the potential of the area and to highlight possible activities addressed to the efficient and effective use of the proposed geoitinerary, we carried out an analysis to define the strengths, weaknesses, opportunities, and threats (SWOT analysis). Results of the SWOT analysis are reported in Table 3.


**Table 3.** Results of the SWOT (strengths, weaknesses, opportunities and threats) analysis.

We then calculated the VSG (value of a site for geotourism) index by applying the Pica et al. [88] method reported in Table 1. Moreover, the Middle Bussento Karst System has a representativeness (RP) value of 5 because it is an amazing example of a subsurface river path with contact ponors representative of the ponor retreat mechanism, and its interest falls in many disciplines, including geomorphology, hydrology, and structural geology. The rareness (RR) index has a value of 5 because subsurface river paths are not so common in Italian territory and the Middle Bussento Karst System is the second longest subsurface river in Italy. The scenic-aesthetic (SCE) value is 5 because viewpoints are common along the entire geoitinerary and cromatic contrast is excellent, thus allowing a full appreciation of the karst landforms. The historical-archeological-cultural index (SAC) has a value of 3 because of restriction laws related to the protected area and to a poor connection with local tradition. The accessibility index (AC) has a value of 3 because the site is easily accessible by car and public transport, but it lacks services close to the stops of the geoitinerary.

The resulting value of the VSG index is 21 suggesting that the Middle Bussento Karst System has a high potential for geotourism.

#### **6. Conclusions**

Karst systems are sensitive environments that deserve accurate management and promotion strategies to avoid contamination of water resources used for drinkable needs and to avoid alteration of the environment, with drastic consequences for the flora and fauna that live in these areas and also for the karst landforms as well. Furthermore, karst landforms are among the more fascinating landforms to attract tourists.

To highlight the natural and socio-economic role of karst areas, we investigated the Middle Bussento Karst System, in the Cilento, Vallo di Diano and Alburni UNESCO Global Geopark by carrying out a comprehensive analysis of both its surface and subsurface karst landforms. The peculiarity of the area is that the Bussento River sinks at the La Rupe ponor, near the village of Caselle in Pittari, and remerges, after 4 km of subsurface path, at the Bussento Resurgence, near the village of Morigerati, making the Bussento River subsurface path the second longest one in Italy and the longest one in Southern Italy. Selected karst landforms include the La Rupe, Orsivacca, Cozzetta, and Bacuta ponors, whose subsurface paths are connected and end at the Bussento Resurgence. In addition, a visit to a local virtual museum (MU.VI.) is included in the geoitinerary. The SWOT analysis also enhances the touristic potential of the geoitinerary, highlighting the high potential of this area as a possible touristic attraction in the Cilento, Vallo di Diano and Alburni UNESCO Global Geopark. This is also testified by the high value of the VSG index, whose score of 21 places the geomorphosite among the areas with high potential for geotourism. Some touristic promotion activity has already been carried out, such as the foundation of the MU.VI., however more actions are necessary to strengthen the role of the Middle Bussento Karst System as a significant geo-touristic attraction. The proposed geoitinerary has high scientific and educational values that may help in the field of environmental education, making people aware about the importance of karst areas as containers of water resources. The combination of the proposed geoitinerary with educational materials could help visitors gain detailed knowledge about what a karst environment is and how it works. Future campaigns of touristic promotion in the Geopark should emphasize the role of the blind valley of the Bussento River as the second longest subsurface river path of Italy and the longest in Southern Italy. Moreover, the addition of possible outdoor activities carried out by local associations could help the growth of tourism.

We tried to contribute to an increase in the curiosity of this site, in order to promote this fascinating portion of the Geopark as a touristic attraction and aid in the growth of the local economy.

**Author Contributions:** Conceptualization, E.V. and N.S.; methodology, E.V. and N.S.; software, E.V.; validation, A.S., D.G., and N.S.; formal analysis, D.G.; investigation, E.V.; data curation, E.V.; writing—original draft preparation, E.V., A.S., and N.S.; writing—review and editing, E.V., A.S., and N.S.; visualization, D.G.; supervision, A.S. and N.S. All authors have read and agreed to the published version of the manuscript.

**Funding:** The research was funded by department research (DISTAR), Nicoletta Santangelo.

**Acknowledgments:** We wish to thank two anonymous reviewers whose suggestions helped to increase the quality of the paper.

**Conflicts of Interest:** The authors declare no conflicts of interest.

#### **References**


© 2020 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).

### *Article* **Fieldtrips and Virtual Tours as Geotourism Resources: Examples from the Sesia Val Grande UNESCO Global Geopark (NW Italy)**

**Luigi Perotti 1, Irene Maria Bollati 2,\*, Cristina Viani 1, Enrico Zanoletti 3, Valeria Caironi 2, Manuela Pelfini <sup>2</sup> and Marco Giardino <sup>1</sup>**


Received: 30 April 2020; Accepted: 27 May 2020; Published: 29 May 2020

**Abstract:** In the 20th anniversary year of the European Geopark Network, and 5 years on from the receipt of the UNESCO label for the geoparks, this research focuses on geotourism contents and solutions within one of the most recently designated geoparks, admitted for membership in 2013: the Sesia Val Grande UNESCO Global Geopark (Western Italian Alps). The main aim of this paper is to corroborate the use of fieldtrips and virtual tours as resources for geotourism. The analysis is developed according to: (i) geodiversity and geoheritage of the geopark territory; (ii) different approaches for planning fieldtrip and virtual tours. The lists of 18 geotrails, 68 geosites and 13 off-site geoheritage elements (e.g., museums, geolabs) are provided. Then, seven trails were selected as a mirror of the geodiversity and as container of on-site and off-site geoheritage within the geopark. They were described to highlight the different approaches that were implemented for their valorization. Most of the geotrails are equipped with panels, and supported by the presence of thematic laboratories or sections in museums. A multidisciplinary approach (e.g., history, ecology) is applied to some geotrails, and a few of them are translated into virtual tours. The variety of geosciences contents of the geopark territory is hence viewed as richness, in term of high geodiversity, but also in term of diversification for its valorization.

**Keywords:** Sesia Val Grande UNESCO Global Geopark; geodiversity; geoheritage; fieldtrips; virtual tours; multidisciplinary approach; Italian NW Alps

#### **1. Introduction**

Geotourism has been defined as "tourism that sustains or enhances the distinctive geographical character of a place - its environment, heritage, aesthetics, culture, and the well-being of its residents" (National Geographic Society, https://www.nationalgeographic.com/maps/geotourism/). In its updated concept, geotourism is rapidly emerging as a form of urban and regional sustainable development [1]. As Earth scientists involved in Alpine geological and geomorphological studies, we focused the diversity of physical characters in a geographical region of the Western Italian Alps for understanding their significance in terms of natural and cultural heritage, and their possible contributions to the development of a sustainable, environmental-friendly geotourism.

From this perspective, we analyzed several sites and areas of geological and geomorphological interests, particularly those with significant scientific, educational, cultural, or aesthetic value, which are collectively named geoheritage sites [2]. This term has been used widely to define geological features valuable to the society because of their uniqueness [3–5] either in terms of scientific value or educational purposes and tourism [6,7].

Even if geoheritage is a generic but descriptive term, it is based on an advanced and inclusive consideration of Earth's landforms, materials, and processes, recalling the geodiversity concept. According to Gray's [8] definition, geodiversity is not just a matter of different features, but also of their assemblages, structures, systems, and contribution to landscapes. The complexity of geodiversity is a challenge for its study, but also an opportunity to be explored for the possible recognition of geoheritage sites and the establishment of tourist destinations for providing local and regional economic benefits [9,10].

As geodiversity represents a basis for the geotourism, it can be considered an important resource for the local and regional development [11]. Therefore, for the effective enhancement of geotourism, we considered both its geological and territorial dimensions:


Such a comprehensive approach can offer relevant contributions to both geotourism activities and sustainable use of georesources (including hydro-georesources, sensu Perotti et al. [18]). Significant, long-lasting, international experiences are available for enhancing geotourism. A European Working Group for Earth Sciences Conservation (EWGES) was created in 1988, then (1993) transformed in the ProGEO association (http://www.progeo.se), devoted to diffusion of activities on Earth Sciences and to the establishment of an international network for geosite inventory and conservation. A similar working group was created within the International Union of Geoscience (IUGS), whose outreach activities were the "Geosites" (global inventory of sites of geological interest) and "Geoparks" (a UNESCO partnership for promoting territories including geosites). This site-based approach has worked extremely well for geoconservation purposes [19,20], although geosites cannot by themselves maintain and enhance geodiversity. If complemented by a "regional geothematic" approach, however, the benefits to geoconservation can be enormous. This approach encompasses a targeted selection of sites to create areas of outstanding value within a certain region, based on the attractiveness of scientific knowledge and the possibility of the sustainable fruition of both cultural and natural heritage [21]. The targeted selection of sites within geothematic areas makes easier efforts of regional geodiversity enhancement through careful planning of investments for local activities such as geotourism. In fact, as schematized by Brilha [22], *geodiversity sites* (*on-site*; *in-situ*) and *geodiversity elements* (*o*ff*-site*; *ex-situ)* could be selected as representative of the geodiversity of a region, and when they are recognized as being of relevant scientific value, they become *geosites* (*on-site*; *in-situ*) or *geoheritage elements* (*o*ff*-site*; *ex-situ*) within the wider context of the geoheritage.

An ideal methodological framework for making geotourism effective could be one devoted to the creation of material and virtual field trips aimed to raise awareness of the importance of our geoheritage, and the need to conserve it, amongst different actors: teachers and students, decision makers and stakeholders, entrepreneurs and the general public [23].

The importance of fieldtrips has been underlined since a long time having the function of a "direct experience with concrete phenomena and materials" [24]. When fieldtrips are then intended for schools, moreover, a learning-by-doing approach is favored, including the activity of "observation, identification, measurements and comparison" [24–26]. Bollati et al. [27], for example, proposed a multidisciplinary approach to physical landscape reading, based on the use of vegetation, to reconstruct the evolution of landforms (i.e., dendrogeomorphology) along a geotouristic itinerary. This kind of approach towards physical landscape evolution under geomorphic processes action, and its different responses according to geodiversity, could also be useful to people for hoping to gain awareness of Earth as a complex system, whose dynamics may induce hazards and risks [27–29]. If these experiences are then proposed in iconic sites (i.e., geosites of national or international relevance; [30]) they acquire even more efficacy.

Digital tools—geo-information, geo-visualization, digital monitoring, and Geographic Information Systems (GIS)—are allowing new approaches to geoheritage assessment and mapping [31,32], and geotourism communication and education [28,33]. Direct interactions between institutions and users, and the general public or schools, are enhanced, and favored on a worldwide scale [34]. Digital tools applications for key geoheritage areas are rapidly evolving, and there are several examples [32,34–37].

An important innovation is that many areas are expanding their reach to a global audience by the use of mobile apps, that are set for running on small, wireless devices, such as smartphones and tablets, rather than desktop or laptop computers. A mobile app can provide navigation aid in general, or can be made specific to a park or other protected area, to provide users with real-time guidance and knowledge as they either explore in the field, or virtually navigate the area at home [38]. Some protected areas provide physical or digital visitors with specialized apps equipped with a virtual park ranger or specialist as storyteller, offering particular views on trails. For example, the PROGEO Piemonte project [23,39] has developed two mobile apps devoted to exploring specific areas in the Western Italian Alps [40]. In the last few decades, moreover, the possibility to instantly share events and news and cross-posting between many platforms at the same time [34], is the favored dissemination of information among people, as it allows them to share their opinions and rate their experiences visiting different sites.

The aims of the paper are, hence, to: (i) illustrate the geodiversity of the territory of the Sesia-Val Grande UNESCO Global Geopark (Western Italian Alps) by means of on-site and off-site geoheritage (sensu Brilha [22]); (ii) to propose different approaches to geoheritage valorization, depending on the features of each specific area, using examples of fieldtrips and virtual tours as container of on-site and off-site geoheritage from the Sesia-Val Grande UNESCO Global Geopark.

#### **2. Study Area**

#### *2.1. Location*

The Sesia-Val Grande UNESCO Global Geopark (SVUGG) is located on the north-east of the Piemonte Region (NW Italy), and encompasses areas of the Verbano-Cusio-Ossola, Biella, Novara and Vercelli Provinces (Figure 1). It is bordered to the west by the Monte Rosa massif, to the north by the Ossola and Vigezzo Valleys towards the Swiss border, to the south-east by Lake Maggiore and, to the south, by an area degrading towards the Po plain. The SVUGG includes, in the north, the whole Val Grande National Park and surrounding territories and, in the south, most of the mountain range of the Sesia river basin, including the whole Sesia Valley, and portions of neighboring territories, such as Valsessera, and Strona Valley.

**Figure 1.** Geographical location of the Sesia-Val Grande UNESCO Global Geopark. On the left, the position of the SVUGG within the Piemonte Region with the protected area's location; on the right, the Digital Terrain Model (5 m resolution, source Geoportale Regione Piemonte; http://www.geoportale. piemonte.it/geocatalogorp/?sezione=catalogo) highlighting the articulation of the relief in the geopark with the main streams, lakes, and peaks.

#### *2.2. The Sesia-Val Grande UNESCO Geopark History*

The Sesia Val Grande UNESCO Global Geopark (SVUGG) is member of the European Geopark Network (EGN) since 2013, and of the UNESCO Global Geoparks Program-UGGP since November 2015. It covers an area of about 2202 km<sup>2</sup> and has a perimeter of around 423 km.

The Val Grande National Park (www.parcovalgrande.it), the first partner of the geopark and entirely located within the geopark, was established in 1992 by the decree of the Italian Environment Ministry. It is recognized as the largest wilderness area in Italy, but also in Europe, and since its creation it protects both habitats and endangered animal and botanical species. The National Park was also established as a Site of Community Importance (SCI) and a Special Protection Zone (SPZ) of the Natura 2000 network, because it preserves 10 priority habitats in its territory. Since 2007, the geological heritage also became a strategic target of the activities in the Park, finally leading to its candidature for the European Geopark Network (EGN).

The second partner of the geopark is the Geotouristic Association of the Valsesia Supervolcano (www.supervulcano.it/home.html), which represents the area of the Sesia Magmatic System (middle and lower Sesia Valley), and includes among its members two Natural Parks: Monte Fenera and Alta Valsesia.

The SVUGG comprises other protected areas as the Natural Park of the Alta Val Strona, the Natural Reserves of Baragge and Fondo Toce, the Special Reserves (UNESCO Heritage Sites) of Ghiffa, Varallo, and Domodossola Sacri Monti, as well as other protected areas (Oasi Zegna, Oasi Bosco Tenso, and Pian dei Sali).

The SVUGG has a website (http://www.sesiavalgrandegeopark.it/) and a social network page where updates on events and initiatives are available (https://www.facebook.com/pg/ AssociazioneSesiaValGrandeGeopark/posts/).

As a whole, the territory of the geopark offers its visitors the opportunity to observe the effects of geologic processes, which formed the continental crust at different depths. It also introduces them to the concepts of global plate tectonics, as it is located astride the Insubric Line, representing a major alpine lineament that marks the boundary between the Central Alps, consisting of intricate refolded basement nappes, and the Southern Alps with S-vergent thrusts [41].

Since the geopark extends from the Monte Rosa massif to the northern boundary of the Po Plain, it also shows the record of past climate changes and of the glacial, periglacial, water- and gravity-related processes, which continuously shape the landscape [42].

Last but not least, the geopark territory is also an open-air museum of the ancient civilization of the Alps, since it preserves the traces of a "stone culture" of different ages: from the Paleolithic human settlements in the Monte Fenera caverns, up to the historical use of local georesources, and the construction of defense works in World War I, by taking advantage of the landscape morphology.

Some research projects devoted to the dissemination of Earth Sciences among schools and general public had the SVUGG as focus area. The most important ones are:


Another relevant project currently ongoing in the SVUGG, and particularly related to the Val Grande National park territory, is the COMUNITERRAE - Maps of Cultural Communities of Alpine Landscapes in the Val Grande National Park (http://www.comuniterrae.it/). It is a project by the Associazione Ars.Uni.Vco and Val Grande National Park, included in the European Chart for Sustainable Tourism. It aims to promote innovative methods to ensure sustainable features, and to clearly communicate the project benefits both to the local and to a wider public. The valorization of assets, places, and components of the material and immaterial heritage of a territory along centuries is the main focus. In 2019 the project was awarded with the European Heritage Award 2019 in the category "Education, Training and Awareness-Raising".

The different aspects of the geopark are then described in the following paragraphs.

#### *2.3. Geology*

The geologic context exposed in the SVUGG territory is of high scientific interest, as witnessed by thousands of papers published in the last 50 years by researchers from all over the world.

The geodiversity which characterizes the geopark results from processes lasted over 500 million years, whose effects are still recognizable in the field.

The SVUGG (Figure 2) is stretched along the Canavese Line (CL), a segment of the Insubric Line, a major tectonic boundary separating the N-vergent nappes of the Central Alps (Austroalpine and

Pennine domains), affected by the Alpine metamorphism, from the S-vergent South Alpine domain [43] (to the SE), a pre-Alpine metamorphosed basement with its sedimentary coverage.

**Figure 2.** Regional Geological setting of the Sesia-Val Grande UNESCO Global Geopark from the ARPA Piemonte Geological map (1:250000) (modified from https://webgis.arpa.piemonte.it/geoportale/).

Most of the territory of the geopark (Figure 2) belongs to the South Alpine domain. Along the CL, which crosses the area in SW–NE direction, the alpine units are represented by the Austroalpine domain, whereas the other nappes (Lower, Middle and Upper Pennine domains) crop out only along the north-western boundary of the geopark.

Therefore, the South Alpine domain and its relations with the Austroalpine domain along the CL are the focus of most of the geotouristic activities proposed to the general public along geotrails, in exemplary geosites (see Sections 4.1 and 4.2), as well as in different thematic museums and laboratories (see Section 4.3). The main geological themes will be described in the following paragraphs.

#### 2.3.1. The Canavese Line

The Canavese Line (CL) (sensu Schmid et al. [44] and Steck et al. [41]) here represents the contact between the Austroalpine domain, to the north-west, involved in the Alpine metamorphism, and the South Alpine domain, to the south-east, which preserves much older structures, despite having experienced some Alpine tectonic deformation in greenschist to anchizonal facies [45].

The Austroalpine domain is here represented by the Sesia-Lanzo Zone, a composite unit (Gneiss minuti and Eclogitic Micaschists Complexes) with a polyphase deformation history (HP/LT; mainly blue-schist to eclogite facies conditions; [46,47]) related to specific phases of the Alpine orogeny (Late Cretaceous–Early Tertiary), and by the II Dioritic-Kinzigite Zone, characterized by micaschists, gneisses, and metabasites in granulite to amphibolite facies [48].

The CL is visible on the field as a greenschist facies mylonite belt [41], up to 1 km thick, which may involve rocks belonging to:

i. The northern border of the Ivrea-Verbano Zone (South Alpine basement), with its Permo-Mesozoic cover;


In the Loana Valley, near the northern boundary of the Val Grande National Park, the mylonite occurrence (i.e., the Scaredi Formation [41]) is particularly meaningful [44,50–52]. There, mylonites derived from the Permo-Mesozoic cover rocks are dismembered, and often imbricated with or folded into the Ivrea-Verbano-derived mylonites; Sesia-Lanzo mylonitized gneiss also occur along restricted bands [49].

#### 2.3.2. The South Alpine Domain

In the SVUGG area, the South Alpine domain is represented by the Massiccio dei Laghi [53,54], which comprises two main lithotectonic units: The Ivrea-Verbano Zone and the Serie dei Laghi. After Ferrando et al. [49], it also comprises the Canavese Zone (see before).

The Massiccio dei Laghi exposes a spectacular cross section from the lower crustal levels of the Ivrea-Verbano Zone to the middle and upper crustal levels of the Serie dei Laghi. It is considered a model for a magmatically underplated and extended crustal section [55,56].

The Ivrea-Verbano Zone mainly consists of two portions:


The scientific importance of the Ivrea-Verbano Zone is once more underlined by the recent Project Drilling the Ivrea-Verbano Zone (DIVE), which, through four drilling operations in the Sesia and Ossola Valleysaims to unravel the physico–chemical properties and architecture of the lower continental crust towards the crust–mantle (Moho) transition [61].

The Serie dei Laghi [54] consists of different units (from NW to SE):


iii. Scisti dei Laghi: mainly garnet and staurolite and kyanite micaschists, with minor paragneiss intercalations.

Thick Orthogneiss lenses are intercalated in all these units, but mainly within or close to the Strona-Ceneri Border Zone. They are metaluminous tonalites to granites with calcalkaline affinity ([66,67] and references therein) and an Ordovician intrusion age around 466 Ma (Rb-Sr whole rock isochron; [68]).

The intrusives and their sedimentary host rocks suffered together the Variscan orogenic metamorphism, mainly in amphibolite facies conditions, recorded by mineral ages of 311–325 Ma [67].

The original contact between the Ivrea-Verbano Zone and Serie dei Laghi is the Cossato-Mergozzo-Brissago Line (CMB; [69]), an important subvertical tectonic lineament characterized by the simultaneous occurrence of three distinctive features [53]: high-T mylonites, migmatites, and mafic to intermediate dykes and stocks (called the "Appinite Suite" [69]), mostly concordant with the CMB mylonitic foliation. The best estimate of the intrusion age of the Appinites is a U-Pb age of 285 ± 5 My [70] on a monazite from a dyke near Mergozzo. The CMB is cut at low angle and dislocated by the Pogallo Line [53], characterized by amphibolite to greenschist facies mylonites and by the lack of Appinite intrusions. In the Sesia sector, the CMB has been reactivated by a younger fault (Cremosina Line; CRL) [53].

The last large-scale event in the Serie dei Laghi was the intrusion of granitic magmas forming different plutons (Graniti dei Laghi) outcropping along the southeastern border of the SVUGG. The most famous of them are the Montorfano and Mottarone–Baveno plutons (dated at 275 Ma [67]).

2.3.3. The Sesia Magmatic System

The Sesia Magmatic System is part of a large Late Carboniferous to Early Permian igneous province [71], a bimodal suite of basic and silicic volcanic and plutonic rocks outcropping across Europe from Spain to Scandinavia in association with extensive crustal rifting. From the lower to the upper levels, it consists of:


#### *2.4. Geomorphology*

From a geomorphological point of view, the Sesia Val Grande UNESCO Global Geopark (SVUGG) preserves several geomorphological landscapes tracing back to the long-term modelling history of the Alpine relief. A diversity of landforms recalls ancient and present surficial processes, which shaped

the landscapes by means of their dynamic interactions with geological and tectonic conditioning factors. As a result, the altitudinal range of the whole SVUGG area is articulated and extreme: from the 4634 m a.s.l. of Monte Rosa to less than 200 m a.s.l. of the Po plain, down to the bottom of Lake Maggiore, a crypto-depression at −179 m. The Geomorphodiversity (sensu Panizza [79]) of the geopark is presented below, with references to both the geological constrains and the morphodynamic processes affecting the geomorphological landscape.

#### 2.4.1. Lithostructural Constrains and Long-term Geomorphological History

The SVUGG area belongs to the Western Alps, an arch-shaped mountain chain which shows, at the regional scale, an asymmetrical transversal profile: the inner SE-facing side is shorter and steeper than the outer NW-facing side. Within the inner side of the Alps (Figure 1), the SE-NW altitudinal profile of the geopark shows morphological steps with distinctive mean elevation: from the upper plain (altitude between 200–350 m a.s.l.), to the foothills (350–1000 m a.s.l.) through all to the mountain relief (1000–4634 m a.s.l.) up the current alpine watershed [42].

At the regional scale, these distinctive morphological steps correspond roughly to the distribution areas of major geological complexes of the Western Alps, namely (from SE to NW): The Quaternary deposits of the Po plain and synorogenic Pliocene deposits, the sedimentary, magmatic, and metamorphic units of the South Alpine domain and the metamorphic units of the Austroalpine and Pennine domains (Figure 2) [80,81].

At the local scale, a diversity of peculiar relationships can be recognized between landforms and lithotypes. Some examples include: enhanced effects of differential erosion along the valleys, where schist units outcrop between massive magmatic or metamorphic rocks, (e.g., the morphological change corresponds to the narrow, deeply incised gorge of the Mastallone river within the hard diorites, while upstream of Fobello, a large valley developed, due to most erodible metamorphic schists); microscale competence contrasts between hard rock inclusions within pyroclastic breccias; subsurface karst landforms for dissolution phenomena of carbonatic rocks.

Moreover, strong conditioning factors to the geomorphological landscape are due to the geometrical setting of regional schistosity, to local geological structures, and to major tectonic discontinuities. At a regional scale, this is particularly evident along the shear zones related to the Canavese, Cossato-Mergozzo-Brissago, Pogallo and Cremosina Lines (Figure 2). As an example, the whole NE sector of the SVUGG is dominated by marked NE-SW (within Serie dei Laghi Unit) and NNE-SSW (within Ivrea-Verbano Unit) trends of morphostructures, either represented by deep incised tributary valleys (Figure 3b) and linear segments of the hydrographic network (Figure 3c).

The alpine valleys across the Geopark develop radially from the Po Valley towards the watershed. The two major valleys (Sesia and Toce valleys) are deeply incised in the bedrock and their slopes sometimes exceed 3000 m a.s.l.. The engravings of these alpine valleys can be dated to the Messinian [82] or to the Pliocene [83]. This long-term geomorphological history is witnessed by landforms and deposits within the Geopark, such as the Lake Maggiore cryptodepression, the deep valleys and the foothills sector where marine sediments were deposited during the Pliocene [84]. This ancient modeling of the mountain chain was followed by the deposition of a continental regressive sedimentary sequence between the middle Pliocene and the lower Pleistocene (Villafranchiano; [84]).

Thereafter, following the climatic changes of Quaternary period, the entire Alpine sector of Sesia Val Grande was repeatedly occupied by important glacial masses. The glacial pulsations have shaped the main valleys of the area, strongly influencing the current geomorphological and hydrographic regional structure.

**Figure 3.** Example of geomorphological features characterizing the Sesia Val Grande UNESCO Global Geopark: (**a**) Tagliaferro peak in Sesia Valley; (**b**) incised tributary stream of the Pogallo Valley; (**c**) linear stream at Balmuccia (Sesia Valley); (**d**) Unipiano and Sacro Monte di Varallo glacial terraces; (**e**) Toce river mouth in the Maggiore Lake, with the Montorfano peak on the right.

#### 2.4.2. "Recent" and Present-day Geomorphological Landforms and Processes

Within an area of large geomorphodiversity, the SVUGG offers both a live demonstration of active glacial processes and a window on past climate changes recorded in the Pleistocene landforms, marked by repeated glacial advances and retreats.

The onset of Quaternary glaciations in the Western Alps led to the formation of a large ice sheet, and major valley glaciers [85]. Within the geopark, both erosional and depositional landforms witness the extent of major Pleistocene glacial modelling phases from the Monte Rosa massif to the Sesia and Ossola Valleys. Starting from the higher elevation areas, erosional landforms such as magnificent nunatak-like mountains are visible (e.g., Mud Horn and Tagliaferro peak, high Sesia Valley, Figure 3a), large and steep U-shaped valleys (e.g., Toce Valley, Figure 3e), as well as trimlines and in-valley sequences of erosional and depositional landforms (e.g., the Unipiano and Sacro Monte di Varallo glacial terraces, examples of further valley deepening after glacial erosional modelling, Figure 3d).

Distinctive depositional features all around the Maggiore Lake witness the Toce and Ticino glaciers extension to the upper Po plain through the Verbano lobe and towards the Orta lake [86] leaving few areas free of ice cover, such as Monte Mottarone, SW of Verbania. According to geomorphological evidences, radiocarbon datings, and numerical models [87–89]; also, the Pogallo Valley was supposedly indicated as of incomplete glacial coverage during the Late Glacial Maximum (LGM, around 24ky BP, in the geopark area), thus making possible survival of older structural and fluvial landforms.

Successively, during the Little Ice Age (LIA, XIV-XIX century), favorable climatic conditions allowed local glacier expansion. Later, SVUGG glaciers experienced a strong retreat; from the end of the LIA until now, they lost about the 50% of their area (from about 7 km2 to about 3.5 km2, [90,91]). Currently, according to the New Italian Glacier Inventory [92] only seven glaciological units exists on the slopes of the Monte Rosa southeast side: four glaciers and three snowfields. As a result of the ongoing climate change, their shrinkage is still underway.

The possible appraisal of several environmental changes through time as a consequence of glacial, periglacial, water- and gravity-related processes, is among the most attractive characters of the geomorphological heritage in the geopark. A thematic representation of the SVUGG geomorphological landscapes is offered in Figure 4, which is a land-systems map created as a factor map for regional assessment of geodiversity within the geopark. GIS synthesis and interpretation of regional datasets with geomorphological contents (hydrography, glaciers, glacial cirques and periglacial features, landslides, debris-flows, and alluvial fans) allowed the recognition of areas characterized by prevalence of a certain type of landforms and related processes. These are useful for regional enhancement of geomorphodiversity and framing of local geosites.

As shown in the map, a large area of the geopark is characterized by the hydrographic basins of two main rivers (Sesia and Toce) and by slopes providing several insights on the effects of water-related processes. The selection of geosites and geotrails concerning fluvial and water related landforms and processes, that could also affect their evolution (e.g., [93,94]), is of great importance for the enhancement of SVUGG geoheritage. This particular aspect of geodiversity (i.e., hydro-geodiversity sensu Perotti et al. [18]), in fact, includes several abiotic ecosystem services that have been recognized of high relevance for the local community, either for their material contents, for the provisioning character (water for human and agricultural consumption and for renewable energy), or for their valuable contribution to cultural and leisure activities (environmental education, tourism, sports).

To complete this geomorphological framework, examples of karst morphologies (i.e., mainly hypogean caves) are also present where carbonatic rocks occur, such as in the Monte Fenera area.

**Figure 4.** A land-systems map created as a factor map for regional assessment of geodiversity within the Sesia Val Grande UNESCO Global Geopark.

#### *2.5. Georesources and Ancient Human Settlements*

Georesources within the geopark territory are strictly related to its high lithological geodiversity and morphological traits. These features are related to the abiotic ecosystem services (such as provisioning and cultural services, as outlined by Gray [8]).

Quarrying and mining were important economic activities in the geopark area and its vicinity for centuries, whereas, at present, all of the mines and most of the quarries are closed and the land rehabilitated, in some cases through geotouristic valorisation activities (see Section 4.3).

The Ossola Valley is one of the most important quarrying areas of the Italian Alps [95–97], materials are used since a long time all around the national territory and also abroad. Several web resources are available to explore this richness (http://www.pietredelvco.it/; http://pietredelcusio.weebly.com/).

The most relevant georesources for the local communities, in the portion of the Ossola Valley within the SVUGG territory, are:


**Figure 5.** Georesources providing abiotic ecosystem services to the community within and outside the Sesia Val Grande UNESCO Global Geopark: (**a**) Mottarone and Montorfano granite: on the left, a rocky chain in Rome city made of Montorfano white granite and the columns in Baveno pink granite; on the right, a view on the Baveno quarry with Montorfano quarry in the background; (**b**) the Cava Madre in Candoglia (on the left), exclusively reserved since 1387 AD for the Milan Cathedral on the right); (**c**) an outcrop with the traditional signs of Pietra ollare extraction (above) and a pot made of the same rock and conserved in the Ecomuseo ed leuzerie e di scherpelit (below, courtesy of Archivio Ecomuseo by Riccardo Rapini).

Concerning the human settlements in the area, both in the Ossola Valley and in the Sesia Valley, there is evidence of human habitation dating back to the Paleolithic, as it would have had favorable environmental conditions. In the lower Sesia Valley, within the karstified Triassic marine carbonate complex of Monte Fenera, caverns utilized by Paleolithic inhabitants can be found [102]. Moreover, famous petroglyphs, carved into different lithologies, probably related to religious ceremonies, are located at the Alpe Sassoledo (Figure 6a), Alpe Prà, Alpe Pianzà (Figure 6b), and Malesco villages, in the Ossola Valley. In particular, the petroglyphs of the Alpe Sassoledo (Figure 6a) were the source of inspiration for the creation of the Val Grande National Park logo. Finally, remnants of an ancient necropolis ascribed to the Leponti population (II-I century BC) were found near Ornavasso [103].

**Figure 6.** The (pre)historical background signs retrieved in different localities withint the Sesia Val Grande UNESCO Geopark: (**a**) Alpe Sassoledo; (**b**) Alpe Pianzà in the Vigezzo Valley; (**c**) Walser tytpical architecture in the Otro Valley.

According to the geographical concept of geotourism we also analysed further development of the use of stone resources in other SVUGG sectors, namely at Alagna ("Im Land" in the Walser German language) an alpine town of Upper Valsesia. This is the access point to the North face of Monte Rosa. It was settled by Walser colonist from Valais, Switzerland in the 14th century: since then it has preserved its alemanic language, culture and architecture (Figure 7c). The present day permanent resident population is about 600 inhabitants, while during winter season, over 5000 tourists per day are present at Alagna Valsesia. It has preserved its pristine character of typical alpine stone village.

Concerning the adaptation of defensive strategies to the morphology of the territory, the geomorphodiversity played an important role during human history. An important historical feature within the geopark is the presence of the Northern defensive border of the Italian territory towards North during the First World War, known as the Linea Cadorna (Figure 7a,b) In the Verbano area and in the lower Ossola Valley, this artificial path makes it possible to reach, relatively easily, high altitude spots in the SVUGG, and has locally become part of geotrails, as described in the results. In the specific case of the Toce Valley bottom, the line passes in correspondence of the narrower part (Stretta di Bara), where the Ossola Valley bottom reaches it lowest width value (about 700 m, (Figure 7c)).

Other examples of this relation are represented by the Special Reserves (UNESCO Heritage Sites) of the Sacri Monti. Among them, the Varallo (Figure 7d) and Domodossola Sacri Monti in particular are located on isolated hills along the Sesia and Toce rivers, respectively, while the Orta Sacro Monte occupy the top of a hill on a peninsula in the Orta Lake (Figure 7e).

**Figure 7.** Military defense and religious buildings withint the Sesia Val Grande UNESCO Geopark; (**a**,**b**) Strada Cadorna at Pian Vadà (**a**) and Monte Spalavera (**b**); (**c**) Strada Cadorna nearby the Stretta di Bara; (**d**,**e**) UNESCO Sacri Monti, located in peculiar geomorphological contexts: Varallo (**d**, photo courtesy of Carlo Pozzoni) and Orta (**e**, Google Earth 3D view).

#### **3. Materials and Methods**

#### *3.1. Geoheritage Analysis*

In the framework of this research, a complete inventory of the on-site geoheritage (i.e., geosites and geotrails; in situ sensu Brilha [22]) and off-site geoheritage (museums, geo-laboratories; ex situ sensu Brilha [22]) has been performed, as potential resources for geotourism.

Concerning the on-site geoheritage, and geosites in the specific, the lists of the geosites included in the area of the SVUGG, retrieved from the geopark documentation, was examined and revised: they were related to both the application and the revalidation dossiers of the geopark. In the first phase of application (2013, http://www.sesiavalgrandegeopark.it/dossier-candidatura.html), during which the greater part of geosites were identified, they were assessed according to a matrix considering their scientific value, educational contents, and relevance as geotouristic destinations. In addition, their potentials for geoconservation, economic valorization, sustainable management, and conscious usage were carefully considered. This qualitative-quantitative method was applied according to the territory administrative boundaries, counting the presence of certain parameters (i.e., 0 or 1), and quantifying some of them (e.g., vulnerability from 1 to 4).

This initial list was then implemented considering the more recent adds related to the UNESCO Revalidation Dossier (2017). These new geosites derive from the most recent researches carried out on the SVUGG territory concerning mainly geosites meaning in terms of cultural geology and geomorphological landscape.

Hence, in the framework of this research, a shapefile containing all these inventoried geosites, with the respective location (WGS84 coordinates), the geometric properties (point, line, area) and a brief description, was created. The elevation of the geosites was extracted from the last Digital Terrain Model of the Piemonte Region (2009–2011; 5 m resolution). In order to provide a homogeneous classification, the geosites were assigned of:

(i) A primary and a secondary scientific interest, according to the topics characterizing each one of them: GM = geomorphology; GRS = georesources; HYD = hydrogeology; M = mineralogy; P = petrography; PAL = paleontology; SD = sedimentology; SS = soil science; ST = structural. Moreover, the primary interest was classified according to its level of importance at the international, national, regional or local scale (sensu Panizza [104]).

#### (ii) Additional interests: A = aesthetic; H = history/archaelogy; S = sport, e.g., [21,105].

All these considerations were made by widening the scope beyond the boundaries of the SVUGG, taking into consideration the scientific researches carried out at the international, national and regional levels, on these geosites and on other similar ones across the Alps.

Concerning geotrails, they were finally inventoried and grouped according to specific topics (GM = geomorphology; GRS = georesources; HYD = hydrogeology; M = mineralogy; P = petrography; PAL = paleontology; SD = sedimentology; SS = soil science; ST = structural). They were described according to type of installations (panels) and support materials (virtual, apps, paper guides). Moreover, they have been put in relation with geosites (related strictly to the geotrails or satellite) and with off-site geoheritage.

The off-site geoheritage has been also inventoried providing a brief description.

These 3 categories (geosites, geotrails and off-site geoheritage) were put in relation each other in specific tables (SF 1–3).

#### *3.2. Methods for Implementing Geotrails*

The second main goal of this work, which was to present solutions for enhanced geoheritage within the Sesia-Val Grande UNESCO Global Geopark, implies the popularization of geodiversity by "translating" the complexity of Earth system contents with simple languages [23], thus allowing a knowledgeable approach not only for people involved in the field of geosciences, but also for the general public and professionals involved in educational activities [27,106]. Currently, it is necessary to start cultural growth based on a process of communication and interpretation of our geological heritage, leading people to observe the processes affecting the physical world with greater awareness [28].

Hence, the trails proposed have been implemented with specific tools. Hence, among the listed geotrails, the most meaningful and representative ones mirroring the SVUGG geodiversity and offering a particular approach to landscape view were described in detail.

In the following subsections, the tools used at the selected geotrails, according to the specificity of each trail, are described.

#### 3.2.1. MobileApp and Websites Tools for Enhancement of Virtual Tours within Geosites

In the last few years, the advancement of digital technologies and the large diffusion of Internet facilities have favored, in the field of cartography, but also for educational purposes [107], the increasing use of electronic devices and the development of dedicated software. In addition to the well-established appeal of videos available on the web [107], examples of these progresses are offered by webmap applications: GIS functionality is combined with Internet technology, allowing the publication of cartographical data integrated with other information, including hyperlinks to images and information [31,108]. These solutions can be valuable and comprehensive instruments to present results of Geosciences researches to the general public. In order to reach these goals and to promote the knowledge and the exploitation of the geosites in Piemonte region, a webmap application and mobile app (Figure 8) have been developed, through which it is possible to reach a large number of people. Moreover, this solution is economical and easy for users: whatever hardware or software configuration they are using for internet connection, and with only elementary computer knowledge, users can access the data shared by the webmap with a classic internet browser.

**Figure 8.** Virtual tours inside the Sesia Val Grande UNESCO Global Geopark–Progeo Piemonte. Virtual App available in IOS and Google Play app stores.

The tools developed in the SVUGG context were largely based on the innovative approach introduced by the multidisciplinary project PROGEO-Piemonte, [23,40], further developed and tested within cooperative research and educational activities of the University of Torino and the SVUGG (H2020-COFUND "Tech4Culture" project). In order to select the most popular routes, popular products, educational initiatives, and public engagement events within the SVUGG were inventoried following the PROGEO-Piemonte standards, thus implementing both the related websites (http: //www.progeopiemonte.it/en/aree/piemonte-nordorientale/; http://www.sesiavalgrandegeopark.it/). Each tour connects geosites and facilities ("stops") providing descriptions of the natural and cultural landscape and interpretations of the related geological and geomorphological processes. The mobile app and webpage include nine different geotouristical tours located within the geothematic areas defined during the project: a tour network allowing people to begin their journey through the geoheritage of the Piemonte Region, considering both geological and cultural aspects. All the map tiles are integrated into the application, in order to avoid the need of downloading the map on the go, which in some cases might result with expensive roaming costs.

3.2.2. Multidisciplinary Educational Fieldworks for Understanding Spatio-Temporal Evolution of the Alpine Landscape

According to the principle of learning-by-doing [109], specific educational tools (learning aid sensu Orion [24]) were set for being expendable by students [27] and useful for teachers, who were often not familiar with Earth Sciences on the field and laboratory works [110]. The aim was to allow users to observe, measure and compare [24,111]. The geotrail along which these tools were implemented was, in particular, focused on the relation between geomorphological processes, climate change, vegetation response, and human settlements (i.e., Earth as a System [112]). Hence, simplified version of the geomorphological map (i.e., geomorphological boxes (Figure 9c) [21]) and simple exercises (Figure 9c), putting in relation geomorphology, dendrochronology, and dendrogeomorphology, were thought to make students work with methodologies of investigations applied by researchers for reconstructing the evolution of the Alpine physical landscape. These activities have been already tested in the framework, among others, of the Erasmus+ Project (see Section 2.2), are available on the panels along the trail, and are going to be freely downloadable from the website of the trail, together with dedicated web-based videos (Figure 9a).

**Figure 9.** Fieldtrips activities inside the Sesia Val Grande UNESCO Global Geopark: (**a**) multimedia video available on the web on the lime kilns history in the Loana Valley for supporting field activities; (**b**) practical demonstration of the lime production in the Loana Valley; (**c**) simple exercises on the activity of geomorphological processes for students in the Loana Valley (modified from [27]); (**d**) fieldtrips with explanation to students of glacial modeling along the Sentiero Azzurro.

#### **4. Results**

The results of the inventory and implementation for geotrails are described here. Supplementary Files (SF 1–4) are available, including tables with the data and images of the on-site and off-site geoheritage.

#### *4.1. Geosite Inventory*

Figure 10a shows the distribution of the geosites in the SVUGG and the complete information is included in SF 1. From a geographical point of view, they spread over the entire area of the geopark with a concentration along the existing geotrails. The elevation range of the geosites varies from about 200 m a.sl., in correspondence of the bottom of the Toce Valley, to more than 3200 m a.s.l. for the Monte Rosa massif.

**Figure 10.** Distribution of the geosites in the Sesia Val Grande UNESCO Global Geopark (**a**), with the relative abundance of geosites according to the Scientific interest (**b**), level of Scientific interest (**c**), and other interest (**d**). Refer also to SF 1.

Considering their primary scientific value (Figure 10a,b), four main geological interests were identified: petrography (P), structural geology (ST), geomorphology (GM), and georesources (GRS). Some of the categories used in the inventory and applied to both geosites and geotrails were not associated with being of primary interest to any of the geosites (HYD = hydrogeology; M = mineralogy; PAL = paleontology; SD = sedimentology; SS = soil science). They are associated with some of the geosites as secondary interest. About half of the geosites (44%) are related to petrographic topics. Geomorphology, including glaciology, and georesources interests are quite equally represented (26% and 21% respectively), while the topic concerning structural geology can be identified in the 9% of the geosites as primary interest. Concerning the level of the scientific interest of the geosites (Figure 10a,c), the majority of them have an international importance (41%) and mainly correspond to the petrographic and structural categories. They are followed, in number, by the geosites with regional interest (34%). Geosites of national and local importance are less represented (10% and 15% respectively). Finally, regarding other interest (Figure 10d), many geosites are characterized by attributes related to their aesthetic value (43%). Some of them present an historical and/or archaeological

interest (28%), and the minority are exploited for sport activities (4%). For 25% of the geosites, none of the mentioned additional interests can be identified.

#### *4.2. Geotrails Analysis*

In the following paragraphs, a selection of seven geotrails, over a total of 18 within the geopark territory reported in Figure 11, is proposed, to show geodiversity of the SVUGG (Figure 12) and the different approaches adopted to involve users (Figures 8 and 9), be they the general public (tourists, amateurs) or students in schools of different orders.

**Figure 11.** Distribution of the 18 geotrails and 13 off-site geoheritage sites in the Sesia Val Grande UNESCO Global Geopark. Refer also to SF 2 and SF 4.

The selection (grey in SF 2) is presented, starting from the petrographic topic (4.2.1; 4.2.2; yellow in Figure 11), through geomorphology and glaciology topics (4.2.3; 4.2.4; 4.2.5; 4.2.6; green in Figure 11), and concluding with a geotrail specifically focused on georesources (4.2.7; violet in Figure 11). The data of each geotrail are reported in SF 2, and more images are available in SF 4. In SF 2 and in Figure 11, the Via Geoalpina is inserted (17, SF 2): it is a complex, regional relevant trail that includes parts of other geotrails described and/or reported in SF 2 (1, 5, 16, 18; h, i, l, SF 4-II). Hence, portions of this regional trail are equipped, but the whole Via Geoalpina is herein marked. Moreover, the Via Alpina and the Sentiero Italia are included in the map too, since they represent non-thematic trails of national relevance. Variations of trails conditions are communicated to visitors near real-time, as, for example, in the case of interruption of trails due to hydrogeological instability processes, such as the one very recently occurred along the Pogallo Valley trail (16 in Figure 11) during May 2020.

**Figure 12.** Geodiversity along the geotrails in the Sesia Val Grande UNESCO Global Geopark: (**a**) Moho surface in outcrop at Premosello Chiovenda (51, SF 1; 18, SF 2); (**b**) Pizzo Stagno landslide (18, SF 1; 1, SF 2); (**c**) Alpe Prà petroglyphs in the Val Grande National Park; (**d**) Caldera megabreccia at Prato Sesia (50, SF 1; 2, SF 2); (**e**) Ciota Ciara cave in the Monte Fenera karst complex (22, SF 1; 10, SF 2); (**f**) panoramic view on the Monte Rosa from the Sesia Valley (31, SF 1; 4, SF 2). For other views on geodiversity along geotrails of the SVUGG, refer also to the SF 4.

4.2.1. "Viaggio Spazio-Temporale Nelle Profondità Della Terra" (A Space-Time Journey Inside the Earth depths; 18, SF 2)

This trail was inaugurated in April 2013. It runs along the mountain slope behind the Vogogna and Premosello-Chiovenda villages and is relatively simple, but with some exposed stretches. It is equipped with 10 thematic panels located on significant outcrops, available on the web, plus one introductory panel at the beginning of the itinerary. It is focused on three main geologic themes, which may stimulate the curiosity of the general public:

i. The boundary between the Central and the Southern Alps (c, SF 4-II) is along the Insubric Line. The attention is focused on the juxtaposition between the Central Alps, consisting of refolded

basement nappes affected by the Alpine metamorphism, and the Southern Alps, which are little affected by that phase and preserving much older structures. The visitors may observe the phyllonites (8, SF 1; b, SF 4-II), produced by the deformation of Austroalpine rocks along the fault zone, and their contact with the mafic granulites of the Ivrea-Verbano Zone (Southern Alps).


The itinerary also allows observations on the geomorphology of the area (glacial, gravity- and water-related landforms). The trail is illustrated in detail in the Geolab "Luigi Burlini" (6, SF 2; e, f, SF 4-II), located in the Vogogna village, near the beginning of the itinerary and in a web-based video (SF 2; g, SF 4-II). Unfortunately, a section of the trail is currently closed for a landslide and the path indicated in Figure 11 and in SF 2 is the part allowed at this moment.

#### 4.2.2. "Il Supervulcano della Valsesia" (The Sesia Supervolcano; 2, SF 2)

The Sesia Supervolcano geotrail was realized within the network of PROGEO-Piemonte geothematic virtual tours and published as a book and online by PROGEO mobile app and Progeo online webmap. The free mobile application (iOS and Google Play versions) and the free webmap page (www.progeopiemonte.it/path/valsesia.html) were published to enhance and promote geological heritage in the Piemonte Region, and specifically in the Sesia Valley. The itinerary proposed consists of 10 stops reachable by car or by short walking trails, and it is supported by the Supervolcano Infopoint in Prato Sesia (7, SF 3). The Valsesia itinerary permits observations on what was going on around 280 Ma ago, in and below an active supervolcano, which extended for at least 25 km deep in the Earth's crust. Today this area is an open-air laboratory: by observing different evidences (1, 4, 6, 16, 20, 23, 24, 25, 26, 33, 41, 47, 50, 58, SF 1), geologists can study the processes that lead an active supervolcano to collapse in a caldera (Figure 12d), after a major eruption (SF 4-IV). The wealth of scientific data and interpretations presented through the stops of the itinerary allows also not expert visitors to reconstruct accurately the history of magmatic processes of the Sesia Supervolcano. Approximately 295 Ma ago, partial melting of the mantle produced magmas that were introduced into the deeper part of the crust, forming the so-called Mafic Complex. About 288 Ma ago, heat from this deep magmatic body melted the upper crust, forming granitic bodies known as the Graniti dei laghi. In both lower and upper crust, hybrid magmas formed as well, due to mixing of magmas of different origin. In the same period, the magmatic activity reached the Earth's surface. Later, about 280 Ma ago, a super-eruption collapsed the volcanic system, forming a caldera with a diameter of at least 13 km: it is estimated that more than 500 km3 of magma were erupted. It is one of the most violent known magmatic events, which evidences are still preserved along Sesia Valley despite the successive geological events. Then, 90 Ma ago, the Earth's crust slowly opened, creating the Tethys Ocean. Only in the last 30 Ma, during the formation of the Alps, the collision between Africa and Europe exposed a slice of the African crust containing the whole magmatic system of the supervolcano (c, SF 4-IV).

#### 4.2.3. L' Anello Geoturistico della Valle Loana (The Loana Valley Geotouristic Ring; 1, SF 2)

In 2019, a geotouristic trail was equipped along the Loana Valley in the Malesco Municipality, thanks to GAL funding from Fondo Europeo Agricolo per lo Sviluppo Rurale (FEAR). The trail is articulated in two parts: (i) the first one runs along the valley bottom; it is a touristic, easily accessible; (ii) the second one reaches the head of the valley as far as the northern border of the Val Grande National Park. Both the proposals were set starting from the existing excursionist trail network and they have both a ring pattern. Six geostops were identified along the trails and equipped with panels

(e, SF 4-I,) containing essential information, and most of them are enriched with simplified mapping tools [21]. The trail is focused on the evolution of the Alpine landscape under glacial, snow-, water- and gravity-related processes, in relation to vegetation and human settlements. Considering these topics, the trail is recommended only in safe conditions. The trail is inserted in the offer of the "Ecomuseo ed leuzerie e di scherpelit - Museo del Parco Nazionale della Val Grande" of the Malesco Municipality (5, SF 3), from which, in 2020 a pdf-format guide to the trail will be made also available, together with virtual videos (f, SF 4-I), in the specific session of the thematic trails. The trail is focused on three main topics:


4.2.4. L'Itinerario Glaciologico del Parco Naturale Alta Valsesia (Upper Sesia Valley Natural Park Glaciological trail, 4, SF 2)

At the beginning of the 1990s, a glaciological trail was equipped in the Upper Sesia Valley Natural Park in the Alagna Valsesia Municipality. Starting from the existing network of local hiking tracks, the trail was set up as a round-trip route. Eight geostops were identified along the trail, each one equipped with display panels. The southeastern side of Monte Rosa belonging to Sesia Valley is the less glacierized among the five sides of the massif. There are no active valley glaciers similar to Gorner (northwestern side), Verra and Lys glaciers (southwestern side), neither large debris-covered glaciers like Belvedere Glacier (northeastern). Nevertheless, thanks to the glaciological trail of the Upper Sesia Valley Natural Park, it is possible to observe magnificent glacial landscapes of high environmental and scientific interest. The aim of the trail is to guide hikers in the observation and recognition of the most evident and significant landforms shaped by glaciers, during their expansion and recessional phases. For this purpose, the first geostop describes past climatic fluctuations: particularly those dating back to the last million year related to Pleistocene glaciations. The seven geostops illustrate three main topics:

i. The process of glacial erosion and related landforms, from the micro to the macro scale—at the beginning of the trail, it is possible to observe the "Caldaie del Sesia" landform system (e, SF 4-V) modelled by subglacial water of the ancient Sesia Glacier. The system is composed by a gorge where the Sesia River is channeled through a rock step, producing a high waterfall, and a huge kettle. Another example is a roche moutonnée with potholes, good example of landforms

related to abrasion and/or plucking processes. Finally, some geostops illustrate large scale erosion processes, particularly those related to the Bors Valley hanging valley and glacial cirque.


Thanks to the information acquired from the display panels during the ascending route, the hikers are invited, during the descent, to identify and recognize glacial landforms by themselves. The glaciological trail of the Upper Sesia Valley Natural Park has been recently included among the glaciological itineraries on the Italian glacial mountains [90,91]. The contents of the trail drive the attention of the geotourists to some of the most important topics of the present-day debate on environmental changes of the glacial environments [114].

#### 4.2.5. Geological-Pedological Trail of the Cimalegna Plateau (Itinerario geologico-pedologico dell'altopiano di Cimalegna; 3, SF 2)

The Cimalegna glaciological-pedological trail is located in the high-altitude plateau (2800–3000 m a.s.l.) at the Western border of the geopark (Alagna Valsesia municipality). For its structural geology context, the Cimalegna plateau (3, SF 1) is an ideal place to examine the geological history of the North-Western Alps, with particular regard to the geological dynamics of the last 200 Ma [115]. Moreover, here, glacial and periglacial features and soils, show a high variety, and the typical pedogenetic processes of this high-altitude cold environment are well expressed. The Cimalegna plateau is also a relevant location for scientific studies promoted by University of Torino. The "Angelo Mosso Scientific Institute" (8, SF 3; a, SF 4-V) was established here on 1907 for physiological studies at high altitude [116], then upgraded by the Geophysical Observatory conducted by Umberto Monterin since 1927 [117] and, later, by the Snow and Alpine Soils Laboratory. Here, the NatRisk research Team (www.natrisk.unito.it) established a base for studies on glacial and periglacial environments [118,119]), and contributed to the recognition of the Cimalegna site as the Alpine site of the Italian Network for Long-Term Ecological Research (www.lteritalia.it), part of the LTER International Network (ILTER; www.ilternet.edu/). The Cimalegna trail was established by the Ente di Gestione delle Aree Protette della Valle Sesia in 2008 [120], to offer public engagement activities for high school students, naturalistic and environmental associations, such as training courses relating to hiking and mountaineering (c, SF 4-V). The circular route of the Cimalegna path starts from the Passo dei Salati, descends to the "Angelo Mosso Scientific Institute", near Bodwitch Lake, continues east to the Col d'Olen (2881 m), climbs up the Corno del Camoscio horn (3024 m a.s.l.) for a 360◦ viewpoint on the southern slope of the Monte Rosa, then it descends back to the Passo dei Salati. Along the trail, eight display panels were placed, illustrating the geological history of this area with photographs and diagrams, starting from an ancient ocean, the Tethys, up to the formation of the Alps, also dwelling on the soils (b, SF 4-V), which are formed here in particular conditions, due to the presence of an almost flat area, of high-altitudes, and extreme climatic conditions. Further engaged research activities are possible at the "Angelo Mosso Scientific Institute", with audiovisuals projections on specific topics [36], and the exhibition of pedoliths of the soils of Cimalegna (reconstruction in the laboratory of an entire soil profile, made using the material taken in the field; [121]) and a collection of lithotypes from the area [120].

#### 4.2.6. Monte Fenera Caves Trail (Sentiero delle Grotte del Monte Fenera; 10, SF 2)

The peculiarity of Monte Fenera is the presence of many caves (22, SF 1; f, g, SF 4-III) which, over the course of thousands of years, have been occupied by living beings of various animal

species, including some extinct ones, such as *Ursus Spelaeus, Merk's rhinoceros*, and even by *Homo neanderthalensis*, whose finds retrieved at Fenera give the mountain the primacy of the oldest prehistoric site in Piemonte [102,122]. An articulated karst system has developed inside the carbonate rocks (limestone and dolomites) of the Monte Fenera. The preservation of these kinds of rocks in Valsesia is the consequence of the tectonics of the area: in particular, of those faults, the most important is the Cremosina Line, that, causing the movement of large rocky masses, allowed the preservation of Mesozoic rocks from erosion as happened in the neighboring portions. The geotrail was set up with 12 explanatory display boards. The first seven panels focus on geology, describing the rocks that constitute the Monte Fenera (from the oldest dating back to 280 Ma ago, to the more recent ones that emerge from the slopes of the mountain relief), and on the structural assets of the area, characterized by important tectonic lines. Two panels are dedicated to the description of the karst system with concretions. The most important caves (22, SF 1) are: "Grotta delle Arnarie" (3500 m of development), "Buco della Bondaccia" (500 m of development), "Ciota Ciara" (200 m; Figure 12e) and "Il Ciutarùn" (about 70 m). At the entrances of the last three caves, a descriptive panel of each individual underground cavity was placed: the development, the speleological and biological aspects, with images of the interior of the caves and of the species adapted to the underground life that live in them or find a temporary shelter. A panel relating to the archaeological excavations made by the University of Ferrara was also placed at the "Ciota Ciara".

#### 4.2.7. Sentiero Azzurro (The Azzurro Trail; 9, SF 2)

The Mont'Orfano (Figures 3e and 5b) is an isolated peak at the end of Ossola Valley, facing both the Mergozzo and Maggiore lakes. Its lithological composition, mainly of white and green granite, together with the presence of local faults, made it to survive to erosion by the Toce Glacier during the Ice Ages, and thus, standing alone, separated from the Mottarone massif, the Massone massif, and the mountains belonging to Val Grande National Park. Due to the presence of granite, it had (and still has, even if reduced) significant importance as a georesource for local communities. On its slopes, for many centuries, about thirty quarries operated to extract big and small rock blocks, mainly used in local buildings, but in the 19th and 20th centuries, lots of sculptures and monuments were made all over the world with the Montorfano white granite. The trail, belonging to the cultural offer of Ecomuseo del Granito (3, SF 3), develops on an easy and historical path, starting from the main village of Mergozzo to reach the small village of Montorfano, just in the middle of the largest quarries, of which only one is still active. Along the path, some panels explain, with the aid of historical pictures, the techniques used in extracting, moving and working the granite blocks (a, b, SF 4-III). Thus, the trail has not only a geological importance, but even an anthropological one, because the quarries have been the only economic resource for decades for the local communities of Mergozzo and the surrounding area. The trail ends at Belvedere, a scenic point of view on Mergozzo and Maggiore lakes (x, SF 1), with an explanatory panel about lake geomorphology and the formation of the first one, in relation to sediment transport rates that have characterized the Toce River (Figures 3e and 9d).

#### *4.3. The O*ff*-Site Geoheritage within the Sesia-Val Grande UNESCO Global Geopark (Museum, Geo-Laboratories)*

In the wide area of the SVUGG there are 13 science museums and Park visitor centers closely linked to the activities and themes of the geopark (SF 3, SF 4). Some of them are directly managed by the Regional Natural Park or the National Natural Park and others are managed by four official ecomuseums (recognized by Piemonte regional law), together with local Municipalities. The Ecomuseum is a tool for the participatory management of the natural and cultural heritage of a territory [123], thus it does not focus only on the scientific aspect and the static element (i.e., a rock collection), but enhances that element in the context of the territory and its community. Moreover, it is not an open-air museum nor a diffuse museum, but it is a cultural container. Only few museums are privately owned, but are usually open to the public during tourist season or on reservation.

This off-site geoheritage represents a very important element for the Earth Sciences knowledge of the area, because each of these entities focuses its attention on a specific topic, sometimes with substantial collections that also have a historical value (i.e., Museo di Scienze Naturali "Mellerio Rosmini", 11, SF 3, and Museo "Pietro Calderini" 9, SF 3). The off-site geoheritage is only not represented by collections of rocks and minerals, but also by specific explanatory sections, inside museums and visitor centers, about the georesources and their use in past and present times. In some cases, there is a strong connection between the archaeological heritage and the geological one (i.e., Ecomuseo ed leuzerie e di scherpelit - Museo del Parco Nazionale della Val Grande, 5, SF 3; f, SF 4-I; Museo Archeologico e Paleontologico "Carlo Conti", 10, SF 3). Many of them are also connected with the on-site geoheritage, are near-by geosites or geotrails, and offer lots of information for the outdoor visits. In two cases, Ecomuseo della Val Toppa (4, SF 3) and Antica Cava (1, SF 3) are actually on-site geoheritage elements (an old gold mine and an old marble quarry), but they are managed as museums, with opening times and guided visits. Some structures offer educational services both for students of all ages and for adults, with the aid of well and specific trained educators and guides. These kinds of activities can join both laboratories and excursions, not only for working on general themes, but also to make the territory and its peculiarities known especially by students in schools. In particular, the Geolab "Luigi Burlini" in Vogogna (6, SF 3; e, f, SF 4-II), was thought as an area for the study and the teaching of themes related to Earth Sciences. It is equipped with a stereo microscope and a polarized light microscope, featuring high-definition video cameras and video devices, and also provides a collection of thin sections of the main rocks in the area, a mineralogical and lithological collection, and interactive instruments with pictures and animations of the main themes related to the geology of the area of the Val Grande National Park.

#### **5. Discussions and Conclusions**

The results of our research indicate that the Sesia Val Grande UGG is an area of high geodiversity, rich geoheritage, and multifold geotourism opportunities. Within the UGG Network, several geoparks are related to a specific thematic, frequently inferable from the name of the geopark itself (e.g., the petrified forest of Lesvos Geopark, Greece; Tuscan Mining Park, Italy; Marble Arch Caves, Ireland and UK). In the present case, the name of the geopark refers to its geographic hubs, the Sesia and Val Grande valleys. Regarding the original idea of the SVUGG, it centers around a "deep" geological focus: The South Alpine domain, where several relevant spots of international scientific value have been selected as geosites with a prevalent interest on petrography of crustal rocks. By also carefully considering the landscape and territorial dimensions of geodiversity and geoheritage, other focal points of the geopark were outlined by this study, here below discussed as contributions for integrating fieldtrips and virtual tours in the perspective of enhanced geotourism.

According to our results, it emerges that geosites are lacking in some areas (e.g., north-eastern sectors like Vigezzo Valley (Figure 1)), along some geotrails no geosites are up to now identified (e.g., Sentiero 117-Carlo Genoni, 7 in SF 2, with its ancient gold mining sites), or some geosites are not even linked through specific geotrails (e.g., geosites of the Cava Madre, 12 in SF, Chiesa di Albo; 13 in SF 1, and the off-site geoheritage of Antica cava, one in SF 3). Considering the absence of geosites mainly within satellite geological units (i.e., the Austroalpine domain and other domains north to the Canavese Line) and their potential significance as cultural geoheritage, they are of fundamental importance for the geotourism of the SVUGG. In fact: (i) they contribute even more to the geodiversity of the geopark; (ii) they are useful to contextualize the geopark reality in the framework of a regional evolution; and, hence, (iii) they are potential new resources for the territories and local communities. The same considerations apply in particular to the geomorphological evidences in such parts of the geopark, which in some cases are very relevant.

As an example, the Vigezzo Valley represents an important geological and geomorphological spot for the geopark where it is possible to retrieve witnesses on Earth evolution at different spatio-temporal scales: (i) the effects of one of the most disastrous hydrogeological instability events in the Western Italian Alps occurred on 7th August 1978 [113]; (ii) the evidences of the tectonic activity of the Centovalli Line, related to the Simplon Line tectonic system and affecting paleoenvironmental settings, as well as current slope instabilities [124]; (iii) the mineralogical richness that allowed the identification of new mineralogical species (e.g., Vigezzite [125]).

Moreover, it emerges that in some areas (e.g., south-western regions of the geopark), the lateral valleys are less valorized from a geodiversity point of view despite important evidences. For example, the Sermenza and Sessera Valleys well represent, from a geomorphological point of view at the small scale, the relevance of the action of fluvial process, which could be compared with that of the glacial processes dominating the major valleys (Sesia and Toce Valleys). The possibility of comparing these main geomorphological processes in the field, just by moving between valleys of different orders is of high relevance from an educational point of view. Finally, the valorization of the remote lateral valleys would help local communities in the enhancement of tourist activities and, in some cases, to help new ones emerge, which corresponds to one of the auspices of UNESCO Global Geoparks.

In the present context of climate change, high-altitude geotrails are essential for raising awareness among the general public of ongoing environmental changes, and the glacial and periglacial areas offer some of the best evidences of these developments (e.g., glacier shrinkage, new glacier lakes formation, permafrost degradation [91,114,118]). Moreover, high altitude geotrails could also contribute to the explanation of the indirect effect of climate change on human settlements in mountain areas (eg., ski resorts, water supply, mountain huts access), and allow to test the fruitor perception about the environmental resources related to climate changes [126]. In fact, essential abiotic ecosystem services for human activities are being severely impacted by the ongoing changes [93]. The effects of the ongoing deglaciations are well perceptible along this kind of trail, where the recolonization of vegetation characterizes increasingly widening proglacial areas [127], where geosites are affected by paraglacial-type transformation [94]. Therefore, the availability of high altitude geotrails represents a strength in areas such as the SVUGG, for bringing attention to the abiotic ecosystem services (sensu Gray [8]). In this framework, a particular focus should be also driven towards hydrogeodiversity [18] and future geosites for enhancing water resources, among which high altitude environments host water towers (i.e., glaciers). For example, according to the results and the comparison with the current state of geoconservation of the Val Grande territory, there are also important areas in terms of hydro-geosystemic services, as they are directly related to the withdrawal and consumption of water (e.g., drinking water, for agriculture, for breeding). There are also areas in which human impact is deeper, and where there are no instances of hydrogeological protection sufficient for a good preservation. Therefore, more studies and insights about these issues are needed.

Hence, among the perspectives for the future there is, on the whole, the implementation of valorization initiatives by means of upgrading the geosites inventory and geotrails proposals, considering the easy accessibility and high educational value of potential resources in those areas, that are under evaluation. All these analyses will be accompanied by more and more detailed investigations on the evolution of alpine landscapes, in areas more sensitive to climate change: for example, at the Indren Glacier and Cimalegna Plateau, within the Monterosa Ski resort, on the southern face of Monte Rosa massif, where the LTER site "Mosso, Passo dei Salati-Col d'Olen" is also present in the area and it is part of the Italian Long Term Ecological Research Network. As proposed in other areas [126], the monitoring of tourists' perception and appreciation about valorization initiatives could be a further aim to pursue.

Finally, more multimedia applications and multidisciplinary activities could be implemented for the already existing geotrails, and for the future-planned ones, after their application in pilot areas, as described herein. More suggestions could also derive from the framework of international exchanges related to ERASMUS+ Projects, as those are being performed in the studied area up to now.

**Supplementary Materials:** The following are available online at http://www.mdpi.com/2079-9276/9/6/63/s1, Supplementary file 1 (SF 1): Table of complete data on geosites, Supplementary file 2 (SF 2): Table of complete

data on geotrails, Supplementary file 3 (SF 3): Table of complete data on off-site geoheritage, Supplementary file 4 (SF 4): Collection of pictures of geosites, geotrails and off-site geoheritage.

**Author Contributions:** Conceptualization, L.P., I.M.B., M.G. and M.P.; Methodology, L.P., I.M.B., C.V., M.G. and M.P.; Software, L.P. and C.V.; Validation, M.G. and V.C.; Formal analysis, L.P.; Investigation, I.M.B., V.C., C.V., M.G. and M.P.; Resources, I.M.B., C.V., E.Z., V.C. and M.G.; Data curation, L.P., I.M.B., C.V., E.Z. and V.C.; Writing—original draft preparation, L.P., I.M.B., M.G., C.V., E.Z. and V.C.; Writing—review and editing, I.M.B., M.G., C.V., M.P., E.Z. and V.C.; Visualization, I.M.B., C.V. and E.Z.; Supervision, M.G. and M.P.; Project administration, L.P. and E.Z.; Funding acquisition, M.G. and E.Z. All authors have read and agreed to the published version of the manuscript.

**Funding:** ERASMUS+ project GEOclimHOME-PRO - Geoheritage and climate change for highlighting the professional perspective. Grant 2018-1-FI01-KA201-047206 (European fundings) Ministry of Education, University and Research (MIUR), Project Dipartimenti di Eccellenza 2018–2022, Dipartimento di Scienze della Terra 'A. Desio' of the University of Milano (National fundings) MIUR PRIN 2010–2011 project "Response of morphoclimatic system dynamics to global changes and related geomorphological hazards" (grant number 2010AYKTAB\_0069) (National Fundings); Fondi Potenziamento della Ricerca – Linea 2 – 2015 (entrusted to D. Zanoni), 2016 and 2017 (entrusted to A. Zerboni) (National fundings) FEASR – Fondo Europeo Agricolo per lo Sviluppo Rurale – L'Europa investe nelle zone rurali (European fundings) PSR 2014–2020 della Regione Piemonte – MISURA 19 – Sostegno allo sviluppo locale LEADER (CLLD - Community Led Local Development LEADER) (Regional fundings) GEODIVE – Compagnia San Paolo bank foudation in partnership with University of Torino, under the funding program 2016; the project "GeoDIVE—From rocks to stones, from landforms to landscapes" was funded with grant #CSTO169034 (Regional fundings).

**Acknowledgments:** The Authors are very grateful to all the municipalities, managers of the protected areas, associations, local population and funders as mentioned along the text. Moreover, they are grateful to the students working inside the geopark territory, the visiting groups and to everybody contributing in enhancing the valorisation of geopark resources.

**Conflicts of Interest:** The authors declare no conflict of interest.

#### **References**


© 2020 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).

### *Article* **GEOTOURISM as a Tool for Learning: A Geoitinerary in the Cilento, Vallo di Diano and Alburni Geopark (Southern Italy)**

### **Nicoletta Santangelo 1, Vincenzo Amato 2,3, Alessandra Ascione 1, Elda Russo Ermolli <sup>1</sup> and Ettore Valente 1,\***


Received: 13 May 2020; Accepted: 2 June 2020; Published: 4 June 2020

**Abstract:** "Geotourism" is a particular type of "sustainable tourism" that is still in an embryonic stage, especially in Italy. The main goal is the transmission of geological knowledge to increase the awareness about geoheritage, geo-resources and geo-hazards. The geoparks represent ideal sites, with a strong educational significance for students, teachers, geo-tourists, and guides interested in geological and environmental sciences, though at different levels. With this in mind, we propose a geoitinerary through some of the most geologically interesting coastal areas in the Cilento, Vallo di Diano, and Alburni Geopark. The aim of the geoitinerary is to provide a good example of how geosites could be promoted through geotourism and used as means of divulgation of geological and environmental knowledge. The selected sites are the San Marco coast, the Licosa Cape and the *Elea-Velia* archaeological area. They are included in the official list of geosites and geomorphosites of the Geopark and have a relevant stratigraphic and geoarcheological value. The San Marco coast and the Licosa Cape are the "best sites" in the Geopark where Quaternary coastal deposits and morphologies are represented. The *Elea-Velia* site is one of the most famous archeological sites in the Geopark, which is also representative of complex human-environment interactions. Despite their high scientific significance, the sites that we have selected are not included in a specific promoting program. We have so tried to fill this gap by providing the scientific background for their geotouristic promotion that could also serve as an instrument for the increase of the local economy.

**Keywords:** geoparks; geosites; geotourism; geological knowledge; geoarcheology

#### **1. Introduction**

The Cilento and Vallo di Diano National Park was founded in 1991 under the law 394/91 and it was included in the United Nations Educational, Scientific and Cultural Organization (UNESCO) World Heritage list in 1998. It gained the title of Geopark in 2010 and became a UNESCO Global Geopark in 2015. Global Geoparks have been defined as "Single, unified geographical areas where sites and landscapes of international geological significance are managed with a holistic concept of protection, education and sustainable development" [1,2]. Several authors [3–6] suggested, among the main purposes of a geopark, the preservation of geodiversity by means of geoeducation and geotourism. Geological education, that is, how geoscience, particularly the geological processes, and society are linked, is a basic resource for the social and economic development of any community because it

increases the sensitivity and awareness of citizens in the respect of the environmental estate and natural disasters. Unfortunately, geological education is still a missing topic [7] as, for instance, in the context of global change and overexploitation of resources [8]. Reference [9] suggests that, by using geological themes significant to the public through interpretive media and educational packages, it is possible to create a "dialogue between the public and Earth's history", leading people towards an understanding of the important processes that control our planet. In this meaning, Geoparks and Geoturism may be very useful. According to several authors ([10–12] and references therein) "Geotourism" is an emerging type of sustainable tourism, which focuses on geosites and furnishes visitor knowledge, environmental education, and also amusement.

In this paper, we propose a geoitinerary along the Cilento, Vallo di Diano and Alburni Geopark coastal area, with the aim to provide a good example of how some geosites and geomorphosites could be promoted through geotourism and used as means of geological and environmental knowledge divulgation. Geologists always use field activity as a tool to teach their students; our goal is to demonstrate that the experience of coming directly in touch with a geological subject may be the most effective approach also for non-expert people. The coastal area of the Cilento Vallo di Diano and Alburni Geopark includes several geomorphosites, which represent good examples of both coastal features and evidence of past sea level fluctuations that occurred in response to global climate change. Several papers have already stressed the importance of increased awareness about climate change in coastal environments, also suggesting geotourism as a key action to reach this goal [13–17]. Coastal zones are typical examples of dynamic and sensitive environments, which evolve through different phenomena that act at different temporal and spatial scales [18]. They represent the interface where the land meets the sea and include river deltas, coastal plains, wetlands, beaches and dunes, reefs, lagoons, cliffs and other coastal features. All these areas are very sensitive to changes in response to sea-level rise or extreme weather events, which may cause or accelerate coastal erosion and retreat [19–21]. Approximately 60% of the world's population lives along coastal zones [22,23], which often represent a major environmental and economic resource, though under risk in the light of the present climatic trend [23] that is enhancing the naturally induced sea level rise. We planned a geoitinerary focused on the geological and geomorphological evidence (namely, sediments and landforms) of both the active dynamics and past sea level fluctuations along various coastal environments of the Cilento, Vallo di Diano and Alburni Geopark. Our aim was to give an example of how geomorphosites may be useful for educational purposes and providing teachers and touristic guides with didactic/explanatory material.

We selected some sites among those listed in the Geopark's geosites and geomorphosites inventory, choosing the ones with the following requirements: representativeness, availability, and potential educational approach. For each site, we chose one or more geological and geomorphological topics that are represented at the "best" and explained them in the simplest way, with the aim to transfer their scientific significance to an audience as wide as possible. To reach our educational goal, we followed the suggestions of Macadam [24], i.e.,: (i) choosing the message we want the tourists bring home, (ii) avoiding geological jargon, (iii) using more pictures and figures than words. In particular, we focused on the following messages:


#### **2. Study Area**

#### *2.1. Geological Setting*

The Cilento, Vallo di Diano, and Alburni Geopark is bounded by the Sele River plain to the north, the Vallo di Diano and the Tanagro River valley to the north-east, the Gulf of Policastro to the south, and the Tyrrhenian Sea to the west (Figure 1). The Cilento region is part of the Southern Apennines, a NE-directed fold and thrust belt developed in Neogene to Quaternary times [25–27]. At the surface, the mountain belt consists of both open marine Mesozoic stratigraphic units and continental margin successions composed of platform carbonates and pelagic deposits, covered by Neogene and late Miocene wedge-top basin clastics [28–30]. Due to the heterogeneous nature of outcropping rocks and its rugged topography, the Geopark is characterized by a very high degree of geodiversity [31,32]. Carbonate massifs with summit karst landscapes, bounded by steep structural slopes, are typical of the inner area of the park (Figure 1). In such ridges, karst cave systems associated with the most important underground water reservoirs of the region are preserved [33–35]. The carbonate massifs alternate with a hilly landscape, with gentle slopes and dendritic drainage pattern, where pelagic and clastic successions dominate [36–40]. They are represented by the Cilento Group deposits (age between 17.7 and 10.8 million years), with the Pollica and S. Mauro Formations, mainly made up of alternating sandstones, marls and puddingstones [41–43]. The basinal successions (age between 65 and 22 million years) are well exposed in the southern part of the study area (Ascea-Velia) and are made up of the Crete Nere formation, dark clayey successions more than 500 m thick [36,44]. All these units have been involved in the complex tectonic history leading to the formation of the Southern Apennine chain, and for this reason they appear strongly deformed by fault and fold systems [37,45]. During Quaternary times (last 2.6 million years), the study area emerged from the sea, and its landscape was shaped by the actions of different geomorphic processes (fluvial, coastal, aeolian) under the control of strong climate variations. Continental and marine Quaternary succession, mainly made up by conglomerates and sandstones, accumulated along the valleys of the main rivers (Alento, Mingardo and Bussento rivers) and along the coast in the areas of Santa Maria di Castellabate and San Marco di Castellabate (hereinafter and in the map of Figure 1 labelled Santa Maria and San Marco, respectively), Palinuro and Marina di Camerota [46–54]. Different kinds of geosites (structural, stratigraphic, paleontological, geomorphological) [55,56] are witnesses of this significant geological heritage and have been listed in the geosites inventory of the Geopark [57]. The latter includes 160 geosites, 36% of which with main stratigraphical, paleontological, and geological value, and 54% of which are considered as geomorphosites. Nevertheless, at ~30 years from the National Park foundation and 10 years from the Geopark recognition, the actions aiming at the promotion and divulgation of the geological estate of the area are still very few [34,35,40,58–63].

**Figure 1.** Location of the Cilento, Vallo di Diano, and Alburni Geopark, with indication of the geomorphological units and locations of the main archeological sites.

#### *2.2. Tourism in the Cilento, Vallo di Diano and Alburni Geopark*

It is important to bear in mind that Geotourism needs tourists. Unfortunately, the number of tourists that every year visit the Geopark is not monitored by both the Geopark management and the local administrations, e.g., municipalities, Provincia di Salerno and Regione Campania. Such a condition hampers the reconstruction of the tourist flux and its yearly/decadal variations, as already noted by other authors [64]. On the other hand, some information on the number of tourists visiting and spending nights in specific municipalities of the Geopark may be extracted from reports and analyses of the Italian Institute of Statistics (www.istat.it) and the Ente Provinciale del Turismo of Salerno [65]. These data indicate that more than two and up to four million people have visited the Geopark in the last four to five years. Information useful to outline the impact of the tourist traffic in the Geopark area is available from the Italian Ministry of Environment (https://www.minambiente.it/, [66]). Such information indicates that in the Geopark area there are 2931 active tourism companies, with 53,765 beds and 8762 people working in tourism-related economic activities. Within the entire Geopark, the coastal belt gets the largest number of both accommodation services and people working in touristic facilities and attractions [65]. Tourism in the Geopark is mainly concentrated in the summertime, with the beaches and coastal areas representing the main touristic attraction. For instance, the coastal areas caught more than 95% of the more than 2.4 million tourists that visited the Geopark in 2017 [66,67]. Worthy to note, among the Italian National Parks, the Cilento, Vallo di Diano and Alburni Geopark gains large visibility on the internet [65] even if an effective communication system through the web has not been developed so far by the Geopark administration.

#### **3. Materials and Methods**

For the selection of sites, we followed the suggestions of Brilha [68], who states that sites with high potential educational value (EV) are those that have geological features that can be easily understood by students of different levels of education, with comfortable and quick access and where students may observe the site under good safety conditions. Similarly, sites with potential tourism value (TV) are those presenting visual beauty enjoyable by the majority of the public, with geological features that can be easily observed and understood by non-specialists, under good safety conditions, and with comfortable and quick access. Therefore, we have followed the Brilha [68] method to assess both the educational (Table 1) and the touristic (Table 2) values of coastal geosites in the Cilento, Vallo di Diano and Alburni Geopark. Moreover, to select the geosites that could be included in the geoitinerary, we analyzed the official list of the geosites of the Geopark reported in Aloia et al. [61] and we selected all the geosites placed along the coastal area that could be considered representative of sea level variations. According to Brilha [68], the educational value of a geosite derives from the sum of the relative scores of twelve indicators and their weights, which are the vulnerability (V), accessibility (AC), use limitations (UL), safety (SA), logistics (L), density of population (DE), association with other values (AS), scenery (SC), uniqueness (UN), observation conditions (OC), didactic potential (DP) and geological diversity (GD). Similarly, the touristic value of a geosite derives from the same indicators of the educational value and their relative weights, with the exception of DP and GD that are replaced by the interpretative potential (IP), economic level (EL), and proximity of recreational areas (RA). Using the criteria listed above, we selected three geosites that gained the highest score of both indexes (Section 4), which are the San Marco site, the marine terrace of Punta Licosa, and the *Elea-Velia* site. In particular, the San Marco site can be considered as the best outcrop of Quaternary coastal deposits with well-preserved sedimentary structures along the entire coast of the Geopark, notwithstanding the presence of other important coastal sites and outcrops [46,51,52,54]. Moreover, the San Marco site is also explicative for the dynamics of rocky coasts and in particular for the formation and evolution of the sea cliffs. The Licosa cape is the best example of a marine terrace in the area of the Geopark. The Licosa cape marine terrace covers an area of more than 4 km in length and up to 500 m in width and has been the object of several scientific publications [47,49,69]. The *Elea-Velia* site is the second most important archaeological site in the Geopark, being only preceded by *Paestum* (Figure 1). Besides its archaeological value, it is also exemplary for the human/environment interaction in a flat coastal area characterised by coastline shifting [47,70–72].




**Table2.**Listofselectedcoastalgeositesandindicatorsusedtoassesstheirtouristicvalue.ThegeositenumberisfromAloiaetal.[61].Thenumberbelow

104–coastal

 caves of Cala Cefalo

3

 1

 1

 2

 4

 2

 4

 3

 2

 3

 2

 1

 4

 2, 15

The high didactic value of these sites makes them suitable for educational activities addressed to the diffusion of environmental knowledge. With this in mind, we consulted all the available literature data about these sites and tried to "translate" the main basic geological concepts to a wider audience, not necessarily having a geological background. Taking into account the suggestions of UNESCO [73] and Macadam [24], we tried to avoid the use of geological jargon, dumbing down the concepts but without losing their scientific integrity. We used photos, sketches, maps, and 3-D reconstructions accompanied by short and simple sentences to explain our messages. In particular, for each discussed topic, we designed explanatory panels that can serve as a guideline [74–76] for both touristic guides and science teachers at different educational levels. We conceived the panels with a design that could be readable on the most common electronic devices (e.g., smartphone, tablets) thus making the panels available for the users during the entire trip.

The 3-D views have been obtained from detail scale digital terrain models (DTM). The latter includes Light Detection and Ranging (Lidar) data obtained by the Italian Minister of the Environment. Lidar data have been imported in a Geographic Information System (GIS) software, Arcgis 10.7© (Redlands, CA, USA), to derive a hillshade map that has been managed by means of the ArcScene module to obtain the 3-D views. The latter have been obtained by applying a 3-times vertical exaggeration and have been rotated, with respect the north, to obtain the point of view that allows the best appreciation of the coastal landforms.

#### **4. Results**

#### *4.1. Geosites Selection*

The location of the geosites selected among those listed in the Geopark official list is reported in Figure 2. The results of the application of the Brilha method [68] are reported in Table 1 (educational use of the geosites) and Table 2 (touristic use of the geosites). Moreover, regarding the accessibility indicator (AC), the selected geosites are often placed along the coasts (geosites n. 92, 93, 94, 96, 102 and 104) and they can be reached only by boats, so we have considered distances indicated by Brilha [68] as distances from the closest harbour. As a result of the evaluation, three geosites gained the highest scores in both indexes, which are the geosite n. 22–Marine terrace of Punta Licosa, geosite n. 24–Sandstones of San Marco, and geosite n. 38–*Elea-Velia*. Consequently, we have selected these three geosites and planned the educational geoitinerary.

**Figure 2.** Locations of 15 geosites placed along the Geopark coast and listed in Tables 1 and 2. Numbers refer to geosite numbers reported in both tables.

#### *4.2. Geoitinerary Topics*

The sites we have chosen are exemplary to explain the sea level fluctuations that occurred on Earth over the last 250,000 years [77–79] in response to the climate cyclicity (eustatic sea level fluctuations). As shown in Figure 3, during this time interval, the sea level has fluctuated between "High" and "Low" conditions, with variations in the range of about 100 m. The "High" conditions relate to "Interglacial" periods, meaning that climate conditions were similar to the present one or even warmer and more humid. In these periods, ice caps and continental glaciers melted and reduced their extensions, causing the rise of sea level at a global scale. The "Low" conditions are correlated with moments (Glacial periods) when the climate was colder and dryer than the present one. During these periods, the ice masses extended, and the sea level dropped down to 120 m below the present sea level.

Looking at the figure, we can observe that 130,000 years ago (Last Interglacial) the sea level was higher than the present one, at the Last Glacial Maximum (20,000 years ago) it moved down to −120 m and, from then, it started rising up to the present altitude. These relative motions of the sea level obviously caused significant variations in coastal environments, such as the shifting of the coastline position.

We think that these simple concepts on the extreme dynamicity of the coastal environment and on the past climate changes should be fundamental for the education of each citizen, from students to administrators and politicians. We planned the geoitinerary trying to explain these main sea level fluctuations, choosing one site for each peak described in Figure 3.

The San Marco site has preserved the evidence of the Penultimate Interglacial, the Licosa Cape site shows forms and deposits of the Last Interglacial, and finally the *Elea-Velia* site allows us to discuss on the Post-glacial sea level rise.

**Figure 3.** Explanatory panel on eustatic sea level fluctuations for the last 250,000 years. The sea level curve was redrawn and modified after References [78,79].

#### *4.3. The Geoitinerary*

The geoitinerary consists of two parts: the first part starts from the center of San Marco village and reaches the Licosa cape. The second part focuses on the archeological site of *Elea-Velia*. It needs at least two days, and the journey from the first stop to the last one implies a transfer by car (32 km). The first part of the geoitinerary includes a nice walk of about 3 km from the San Marco harbourharbour to the Licosa cape, with no significant altitude variations (Figure 4).

**Figure 4.** The itinerary of the first day: (**A**) location of stop 1 and 2; (**B**) the walk from the center of San Marco, down to the coastal cliff and the harbour; (**C**) detail of the access to the walk from the San Marco harbour towards Licosa cape.

4.3.1. First Part: the San Marco Sea Cliff and the Licosa Cape Stops

**Main topic**: evolution of rocky coasts **Contents**: sea cliff, marine deposits, marine terrace

Stop 1: San Marco Sea Cliff and Marine Terrace

After parking in the center of the San Marco village, the tourist may direct towards the sea. The pedestrian pathway along the cliff offers a good occasion to explain what a coastal cliff is, how it forms, and how it evolves during time (Figure 5). Following the tracks, it is possible to reach the sea, observing the cliff and the wave-cut platform located at its foot. The latter is well exposed if the sea is flat and in low tide conditions. It is also possible to observe that above the platform, there are several blocks and masses, fallen from the cliff: this site may be useful to understand that a cliff is a dynamic, not static environment, which is moving backward ("retreating") over time. The lower part of Figure 5 (coastal hazard) explains how the normal evolution of a cliff may interact with human activity causing risk conditions for both human properties and lives.

This site is also representative because it preserves the best exposure along the coast of the Geopark of ancient coastal marine sediments related to the Penultimate Interglacial (around 200,000 years ago [55]) with well-preserved sedimentary structures (Figure 6). Looking at the cliff, even a casual tourist may catch the spectacular geometric design drawn by the nature on this rock.

In particular, the cliff is made up of ancient coastal sands, which are now uplifted and form a wide depositional terrace over which the village of San Marco is built (Figure 7). The good exposure of well-preserved sedimentary structures makes this site significant for educational purposes for geological science students. They may come in touch with sandstones and their textures and may observe different kinds of sedimentary structures, testifying for a submerged beach environment. Instead, around 200,000 years ago, the area now occupied by the village of San Marco was invaded by the sea, becoming a gulf, and sands were deposited at the sea bottom. These sands now lie at 15–20 m above the sea level, an altitude higher than the eustatic sea level related to the Penultimate Interglacial (Figure 3). This means that the land moved upward (tectonic uplift) with respect to the sea and the deposited sands emerged, forming the San Marco marine terrace. Geologists name this kind of marine terrace as "raised marine terrace".

**Figure 5.** Explanatory panel on coastal cliff formation and evolution.

**Figure 6.** Explanatory panel on the ancient marine deposits outcropping in the San Marco sea cliff.

#### 79

**Figure 7.** Explanatory panel on the San Marco raised marine terrace.

#### Stop 2: The Licosa Cape

From the harbour of San Marco, the geoitinerary continues towards the Licosa cape. The path starts behind the Approdo Hotel and, after a 1 h walking (Figure 3), it reaches the Licosa cape, where it is possible to have a spectacular view on the little island of Leucosia, so named after one of the mythologic mermaids which distracted Ulysses during its navigation.

The Licosa cape is characterized by the presence of a wide marine terrace (Figure 8) carved by the sea on the Miocene bedrock. It represents an ancient abrasion platform, formed during the Last Interglacial period, when the sea was 6–8 m higher than the present one (Figure 3). Differently from the San Marco terrace, in this case, the altitude of the terrace coincides with that of the sea level (eustatic level; Figure 3) meaning that the land was not uplifted. Geologists refer to this kind of marine terrace as an "eustatic terrace". Along the southern part of the promontory, it is possible to observe that the terrace is locally covered by marine deposits mainly made up of fossil corals and red algae. Geologist were able to define the age of these fossils by means of complex geochemical techniques (in particular, U/Th dating, see Iannace et al. [57] for further details).

**Figure 8.** Explanatory panel on the Licosa cape eustatic marine terrace.

#### 4.3.2. The *Elea-Velia* Geo-Archaeological Site

#### **Main Topic:** evolution of flat coasts

**Contents:** coastal progradation; alluvial fan; human-environment interaction

The Archaeological Park of *Elea-Velia* lies in the alluvial-coastal plain of the Fiumarella River and can be reached from San Marco driving towards South the road named SS267 (Figure 9).

**Figure 9.** Transfer from San Marco to the Archaeological Park of *Elea-Velia*.

The Graeco-Roman town of *Elea-Velia* was founded by the Phoceans in the VI century BC and developed as a Roman town up to the IV century AD when it was abandoned due to both harbour infilling and burial of most of the lower quarters by alluvial deposits [70,71]. For these reasons, this site is explicative of two geomorphological processes: the coastal progradation and the alluvial fan deposition. Both phenomena interacted with human activity from the town foundation up to its abandonment. Within the Archaeological tour of the Park, we suggest two stops which allow for an understanding of the paleogeographical evolution of the area as well as the main environmental changes of the last millennia, including the repeated events of flooding, which caused the burying of the ancient town. Although it is one of the most important touristic attractions of the Geopark, with a number of visitors ranging from 25,000 to 35,000 per year in the period 1996–2018 [80], this peculiar geoarchaeological aspect has not yet been the object of any educational project.

#### Stop 1: The Acropolis

From the *Acropolis* it is possible to have a wide view on the flat territory surrounding the hill, down to the sea. In this part of the tour, we will focus on what happened during the Postglacial period, when the sea level was rising from −120 m (Last Glacial Maximum) up to its present position. Looking at the eustatic sea level curve of the last 10,000 years (Figure 10), we may observe that there is a variation in the rate of sea level rise at around 7000 years ago. Before that moment, the curve is very steep, suggesting a very rapid sea level rise that resulted in a general submersion of flat coastal areas. For this reason, when the Greeks colonized the territory, the *Acropolis* hill was a promontory bounded by two gulfs, that extended in place of the present Alento (to the NW) and Fiumarella (to the SE) plains [48]. Active sea-cliffs were shaped along the rocky coasts, whereas in front of the flat alluvial-coastal plains, sand ridges isolated lagoon environments that were suitable places for landing.

Why is the Acropolis hill now located hundreds of meters inland with respect to the present coastline? The answer is in the complex interaction between coastal processes and sea level fluctuations [81–83]. From 7000 years ago up to now, the rate of sea level rise decreased and was compensated by the incessant sediment supply from inland (Figure 9). For this reason, the coastline started to move towards the sea, and this phenomenon is called "coastal progradation".

**Figure 10.** Explanatory panel on paleogeographic condition of the *Elea-Velia* site before and during the Greek colonization.

Stop 2: Via di Porta V

This stop allows the visitors to have a look at the sequence of alluvial fan deposits that damaged the structures of the Southern Quarter all along the life of the Graeco-Roman town. The alluvial deposits came from the erosion of the stream catchments cutting the slopes at the rear of the Southern Quarter, within the town perimeter (Figure 11). The sedimentological characteristic of the alluvial deposits exposed in the section (massive, badly sorted, and poorly stratified pebbles, sands, and silts) clearly indicates that these alluvial events occurred mainly as debris flow, i.e., the water transported high quantity of debris, behaving as a high-density fluid. The intensive fan deposition caused the town abandonment after several phases of restoration. From that moment, a few other floods affected the area up to the V century AD, when flooding was definitively interrupted [72,83].

**Figure 11.** Explanatory panel on the alluvial events that caused the burying of *Elea-Velia.*

#### **5. Discussion and Conclusions**

The objective of our work was to provide an example of how geosites, and in particular those with high didactic value, may be used for educational purposes. Bearing in mind our aim, we chose those that are the "best sites" in the coastal belt of the Geopark and built a didactic path. Unfortunately, up to now, the educational itinerary in the area is still a missing topic, and when consulting the Geopark web page it is possible to find only general information about the geology of the Geopark, the wildlife, and the vegetation. The Geopark website, in fact, suggests only one poorly detailed itinerary in the karst area of the Bussento river [84]. In such a context, the paper herein and one recently published [35] address the potential educational value of geosites in the Cilento, Vallo di Diano, and Alburni Geopark, and they may be used as examples of how to use geosites to divulge geological knowledge to a wide audience. By adopting a similar geological approach, didactic routes may be organized within the Geopark, choosing the best sites for various environmental topics.

International tourism is a fundamental economic resource for the coastal areas of the Cilento, Vallo di Diano, and Alburni Geopark [65,66]. In fact, the economy of the coastal areas is mainly based on international tourism, although it is mainly focused during summertime, and the preferred touristic destinations are the beaches and the archeological sites of *Elea-Velia* and Paestum [66,67]. Considering that any development of the Cilento, Vallo di Diano, and Alburni Geopark should be based on the enhancement of local resources through the active cooperation of all local actors [67], our work may be an incitement for the Geopark administrators to develop educational activity as a source for touristic interest. The development of such an activity might also contribute to extending the tourist presence beyond summertime, over most of the year.

To analyze the potential of the geoitinerary and to highlight possible activities addressed to its efficiency and effective use, we also defined the strengths, weaknesses, opportunities, and threats through the SWOT analysis, whose results are reported in Table 3.

We strongly believe that increasing the base geological knowledge of each citizen, from the student to the politician or the administrator, may contribute to increasing the awareness in respect to the evolution of our planet and its environmental systems. Indeed, to achieve integrated management of resources and spaces in a coastal area, it is critical to understand the possible change patterns, which differ substantially in the two environmental scenarios we have focused on, i.e., the sea cliffs and coastal plains. For instance, given the widespread and in some instances dense use of coastal land, it is crucial for people to become acquainted with the risk under which properties, people, and their economic activities are eventually posed by coastal recession and instabilities in both the short and long terms. The scenarios that we selected as sites for visits represent meaningful examples of the instability of both rocky coasts under the current, meteorologically-driven coastal dynamics, and low-lying coastal areas exposed to the impact of future sea level rise. Now more than ever before, it is mandatory to generate public awareness about geology and environmental conditions related to global climate change. Issues such as coastal erosion and submergence of coastlines are becoming popular and, in this respect, evidence of the striking environmental impact of the relatively-subdued sea level rise that occurred in the *Elea-Velia* area appears as a meaningful exemplification of possible future change in comparable scenarios.

Geotourism may be one of the most useful tools to spread knowledge on the dynamicity of the natural environment. However, to reach this goal, individual and/or group visitors should get knowledge in advance through guide boards and educational or informational image data. With our work, we tried to achieve such an objective and our wish is that the explanatory material we designed may constructively support geopark guides and teachers aiming at promoting the Geopark area and spreading geological knowledge, respectively, through geotourism.

**Table 3.** Results of the SWOT (strengths, weaknesses, opportunities and threats) analysis about the development of Geotourism in the Cilento, Vallo di Diano, and Alburni Geopark.


Finally, we intended for the interdisciplinary perspective we propose for the *Elea-Velia* archaeological site to serve as a contribution to increasing its touristic interest. We selected *Elea-Velia* to suggest that, for an archaeological site, the availability of geological information which integrates information on historical or cultural issues through the explanation of the environmental conditions that existed during the human frequentation may provide the tourist with a more comprehensive view of the interaction between human activities (agriculture, commerce, etc.) and the natural landscape. This may be a new approach for the valorization of archaeological sites. Archaeological heritage is one of the most important economic resources of Italy and, particularly, of the Campania region, where numerous archaeological sites ranging in value from global to national and regional interest are located. Most of those sites, besides telling of history, architecture, and figurative art, bear the legacy of geological and/or geomorphological processes and human—environment interaction. Despite this, there is still no effort, even in the most important sites such as *Pompeii* and *Herculaneum* excavations, to divulge the natural aspect of the archaeological sites [85,86]. As we believe that learning from the past is crucial to understand the present and future environmental crisis, we have put the attention on the "other stories" that an archaeological site may narrate to its visitors.

**Author Contributions:** Conceptualization, N.S., A.A. and E.R.E.; methodology, N.S. and E.V.; software E.V.; validation, N.S., A.A. and E.R.E.; formal analysis, V.A.; investigation: San Marco Licosa area: N.S., A.A. and E.V.; Elea-Velia: V.A. and E.R.E.; writing—original draft preparation, N.S. and E.V.; writing—review and editing, N.S., A.A., E.V. and E.R.E.; visualization, A.A., E.R.E. and E.V.; supervision, N.S. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research received no external funding.

**Acknowledgments:** We wish to thank three anonymous reviewers whose suggestions helped us to improve the manuscript.

**Conflicts of Interest:** The authors declare no conflict of interest.

#### **References**


© 2020 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).

#### *Article*
