**Contents**


Reprinted from: *J. Mar. Sci. Eng.* **2021**, *9*, 1379, doi:10.3390/jmse9121379 .............. **163**


Organic Geochemical Signatures of the Upper Miocene (Tortonian—Messinian) Sedimentary Succession Onshore Crete Island, Greece: Implications for Hydrocarbon Prospectivity Reprinted from: *J. Mar. Sci. Eng.* **2022**, *10*, 1323, doi:10.3390/jmse10091323 ............. **371**


#### **About the Editors**

#### **George Kontakiotis**

George Kontakiotis achieved Ph.D. degree in Paleoceanography in 2012 at the University of Athens, where he later worked as Laboratory and Teaching Staff in the fields of Marine Geology and Sedimentology. His major research contributions include developing novel approaches on the distribution and pathways of diagenesis in Mg/Ca paleothermometry. He has further worked on sedimentological and paleoceanographic reconstructions at different time scales by means of marine cores and land sections. His main research topics are summarized as follows: environmental sedimentology; marine petroleum systems; exploitation of natural energy resources; integrated bio-cyclo-tephro-stratigraphy; carbonate reservoirs; calibration–validation-application of geochemical proxies for sea surface temperature (SST) and salinity (SSS); applied environmental micropaleontology as a bio-monitoring tool; sea-level variations; ocean/climate changes.

#### **Assimina Antonarakou**

Assimina Antonarakou is a Professor of Marine Geology–Micropaleontology–Didactics on Geosciences, and President of the Faculty of Geology and Geoenvironment at the University of Athens. Her PhD Thesis dealt with Miocene cyclic sedimentary successions of the eastern Mediterranean in terms of orbital periodicities and paleoclimatic variations based on planktonic foraminiferal assemblages. Her main research topics are summarized as follows: planktonic foraminiferal eco-biostratigraphy, geobiology and paleoceanography; astronomical frequencies in paleoclimates; extreme geological events; marine environmental monitoring; ocean dynamics and sea-level changes; natural and human environmental stressors; foraminiferal trace metals and stable isotopes. She has participated in several national and international projects focused on multiproxy ecosystem responses to past/present environmental events, and she is the co-author of more than 70 peer-reviewed publications in international journals.

#### **Dmitry A. Ruban**

Dmitry A. Ruban is Associate Professor at the Southern Federal University. He received his C.Sci. (Geology and Mineralogy) degree from the Rostov State University (Russia) in 2004 and Ph.D. (Geology) degree from the University of Pretoria (South Africa) in 2009, to be followed by M.Sci. (State and Municipal Governance) degree from the Southern Federal University in 2021. His research interests are linked to Earth and environmental sciences (stratigraphy and sedimentology, palaeobiology, tectonics, physical geography and geomorphology, and environmental issues), tourism (also geotourism), and economics and management. Particularly, some of his research projects have focused on Phanerozoic mass extinction, megaclast nomenclature, and geoheritage assessment. He has published over 200 peer-reviewed articles in international journals, and he is member of the editorial board of several international and national journals.

#### **Preface to "Recent Advances in Geological Oceanography"**

#### **Geological Oceanography: Towards Conceptual Frame**

Investigations into modern oceans, seas, and their coastal zones, as well as marine ecosystems, provide valuable information for deciphering geological dynamics. For instance, studies on shores are essential for the development of sediment classifications and conceptual treatment of sedimentary differentiation. Similarly, observations of traces made on the sea-bottom by various organisms facilitate ichnological interpretations for the understanding of the deep past. Indeed, geological oceanography is not only about the present. It pays significant attention to ancient marine deposits, palaeoenvironments, and fossils, some (if not many) of which do not have modern analogues. Importantly, this discipline provides clues for solution to various practical tasks related to mineral and hydrocarbon deposits, which occur beneath modern oceans and seas or are formed in connection to vast ancient water masses. Indeed, emerging directions of geoscience research, such as geoheritage studies, are also linked to geological oceanography because significant portion of unique geological and geomorphological objects represent either ancient or modern environments.

In regard to the above, geological oceanography appears to be a vast field of research. Its conceptual frame needs regular update due to two reasons. On the one hand, numerous investigations bring a lot of new lines of evidence. On the other hand, planning research in this field requires systematic arrangemen<sup>t</sup> of the huge amount of knowledge to outline gaps and perspective directions. Indeed, nonsingle article or monographs can address these challenges comprehensively, but joint efforts of specialists with different research interests and representing different countries can contribute to the demanded conceptualization of geological oceanography.

The present Special Issue is comprised of around two dozen of research papers, which address various issues of geological oceanography. Although each of them focuses on a particular topic, and often a particular region, they mark the recent advances of this discipline, and, taken together, they are valuable for realizing the complexity of the conceptual frame of geological oceanography. Below, we try to overview the content of this Special Issue systematically, trying to find common ground for such diverse, but conceptually important, research. Generally, four main themes can be outlined, namely: modern marine geological environments, quaternary marine studies, palaeoenvironments and palaeoecosystems, and applied marine geology.

The themes considered in the present Special Issue, and the particular research questions raised in our 21 contributions, allow us to outline three general lessons from the recent advances in geological oceanography. First, this discipline does not only concern modern geological processes in oceans/seas and marine palaeoenvironments, taken separately. Rather, there is a kind of continuum between the two noted research domains. Second, it is geological oceanography that reveals various unexpected and unevident links and relationships in planetary dynamics, including those between remote domains of the Earth. Third, this field is not only theoretical, but also for diverse applied research. The range of possible applications is truly wide. Indeed, a lot of research questions in this discipline remain unanswered, and many are even ye<sup>t</sup> to be posed. For instance, more attention should be paid to the state of Precambrian oceans, the anthropogenic factors of marine sedimentation (even on the planetary scale), and marine and underwater geoheritage. These and others research topics must be treated in-depth, and their outcomes should be put into the wide conceptual frames to achieve the maximal effect for the overall development of geological oceanography.

> **George Kontakiotis, Assimina Antonarakou, and Dmitry A. Ruban** *Editors*

#### *Editorial* **Geological Oceanography: Towards a Conceptual Framework**

**George Kontakiotis 1,\*, Assimina Antonarakou 1 and Dmitry A. Ruban 2**


Research into modern oceans, seas, and their coastal zones, as well as marine ecosystems, provides valuable information for deciphering the geological dynamics. For instance, studies of the modern sea floor are essential for the analysis of sedimentary facies and conceptual environmental reconstruction through the integration of sequence stratigraphic and sedimentary models. Similarly, observations of traces of life from various organisms on the sea bottom facilitate ichnological interpretations of the deep past. Geological oceanography is, however, not only about the present, as it also includes marine deposits, palaeoenvironments, and fossils, some (if not many) of which do not have modern analogues. Geological oceanography also provides important frameworks for interpreting mineral and hydrocarbon deposits, which occur beneath modern oceans and seas, or are formed in connection to significant ancient water masses. Geological oceanography also includes emerging directions of geoscience research in the form of geoheritage studies, as a significant portion of unique geological and geomorphological objects represent either ancient or modern environments.

Geological oceanography is, therefore, a broad field of research. As such, any conceptual framework needs to be regularly updated due to two reasons: On the one hand, numerous investigations bring a multitude of new lines of evidence. On the other hand, planning research in this field requires systematic arrangemen<sup>t</sup> of the prior observations and knowledge to outline gaps and interpretive perspectives. No single article or monograph can address these challenges comprehensively, but joint efforts of specialists with different research interests and representing different countries can contribute to the ongoing conceptualization of geological oceanography.

The present Special Issue comprises twenty-one research papers addressing various issues of geological oceanography. Although each of them focuses on a particular topic and often a particular region, they mark the recent advances of this discipline, and, taken together, they are valuable for realizing the complexity of the conceptual framework of geological oceanography. Below, we introduce the content of this Special Issue systematically and outline the common aspects across the discipline. Generally, four main themes can be outlined: modern marine geological environments, Quaternary marine studies, palaeoenvironments and palaeo-ecosystems, and applied marine geology.

The first theme represents the diversity of geological processes in the modern marine environment. Petropoulos et al. [1] demonstrate how the interaction of different forces, including wave activity, landslides, and human activity, influence sediment transport and beach dynamics in a bay of the small island in the Ionian Sea. Hussian and Al-Ramadan [2] investigate the deeper environment, where sands in fans facilitate carbon burial and enhance long-term carbon cycling. Yutsis et al. [3] recognize several contourite depositional systems in the Caspian Sea, which is evidence of a complex organization of deep-marine sedimentation in the enclosed basin. Hayat et al. [4] document the spatiotemporal variations in the coccolithophore fluxes in the Eastern Mediterranean, which are partly dependent on deep-water hydrogynamics; the related processes reflect some patterns of bio-geodynamics in the deepest parts of this sea.

**Citation:** Kontakiotis, G.; Antonarakou, A.; Ruban, D.A. Geological Oceanography: Towards a Conceptual Framework. *J. Mar. Sci. Eng.* **2022**, *10*, 2027. https://doi.org/ 10.3390/jmse10122027

Received: 5 December 2022 Accepted: 15 December 2022 Published: 19 December 2022

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**Copyright:** © 2022 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 (https:// creativecommons.org/licenses/by/ 4.0/).

The second theme reflects the evolution of marine environments and ecosystems throughout the Phanerozoic. Tolokonnikova and Ruban [5] demonstrate how the series of biotic and environmental crises made bryozoans vulnerable to external negative influences at the Devonian–Carboniferous transition. Ali et al. [6] document shelfal sedimentation in the Late Permian of the Salt Range of Pakistan. Garcia et al. [7] undertake a state-of-the-art approach to identify as many as ten taphofacies in the Late Jurassic coquina deposits of the Lusitanian Basin. The investigation by Wang et al. [8] offers an explanation of how deep-sea sediments with rare earth elements and yttrium found from the Pacific formed as a result of local topography (seamounts) and significant palaeoceanographical re-organizations in the Oligocene–Miocene. Ruban [9] implemented a historical approach to gather the old data for accurate outlining of the changes in the configuration of the Late Miocene Tanais Bay of the Paratethys Palaeosea. The insightful and comprehensive review by Johnson [10] focuses on the Pliocene episode of warmth when tropical cyclones became an important factor of sedimentation.

The third theme comprises Quaternary marine studies. The work by Arce-Chamorro et al. [11] traces interrelations between sea-level changes, coastline dynamics, and aeolian dune development at the very edge of the Iberian Peninsula in the Late Pleistocene– Holocene. Wang et al. [12] establish the sedimentary and geochemical archives of the global mid-Pleistocene climatic changes in the Central Pacific and demonstrate the links between the processes in this deep-ocean domain and the remote Asian landmass. Giamali et al. [13] report the Holocene ecological patterns from the North Aegean Trough, where water column stratification and upwelling influenced foraminiferal and pteropod assemblages.

The fourth theme considers the application of the marine geological process to the understanding of petroleum geology. Maravelis et al. [14] characterize the Upper Miocene possible source rocks and the related traps in the Crete Island. Janjuhah et al. [15] classify porosity in the Miocene carbonate reservoirs from Malaysia. Two contributions address the issue of overpressure in marine sediments. Li et al. [16] characterize physical, chemical, and biological mechanisms of overpressure development, with special attention given to gas hydrate systems. Dubinya et al. [17] describe various methods for prediction of overpressure zones. The other application is linked to deep-sea mineral resources. Dai et al. [18] consider seafloor massif sulphides in light of simulation experiments. Environmental aspects are also addressed in this Special Issue. Fazal et al. [19] interpret geochemical patterns of shales accumulated in the Cretaceous Hazara Basin (Pakistan) and note that the high amount of some elements in these shelfal deposits can lead to pollution of both soils and water. Khan et al. [20] demonstrate that both natural and anthropogenic factors influence the sedimentary processes in the Indus River basin and, particularly, the fan of this massive river. Finally, research in geological oceanography has importance for geotourism applications. Ruban [21] explains how finding evidence of palaeoislands of the Mesozoic Caucasian Sea facilitates the evaluation of the regional geoheritage resources and their potential for geotouristic use.

The themes considered in this Special Issue and the particular research questions raised in the 21 contributions point to the contemporary agenda of geological oceanography. Nonetheless, a number of research questions in this discipline remain unanswered. For instance, more attention should be paid to the state of Precambrian oceans, the anthropogenic factors of marine sedimentation (even on the planetary scale), and marine and underwater geoheritage.

**Author Contributions:** Conceptualization, G.K., A.A. and D.A.R.; methodology, G.K., A.A. and D.A.R.; software, G.K., A.A. and D.A.R.; validation, G.K., A.A. and D.A.R.; formal analysis, G.K., A.A. and D.A.R.; investigation, G.K., A.A. and D.A.R.; resources, G.K., A.A. and D.A.R.; data curation, G.K., A.A. and D.A.R.; writing—original draft preparation, G.K., A.A. and D.A.R.; writing—review and editing, G.K., A.A. and D.A.R.; visualization, G.K., A.A. and D.A.R.; supervision, G.K., A.A. and D.A.R.; project administration, G.K., A.A. and D.A.R.; funding acquisition, G.K., A.A. and D.A.R. All authors have read and agreed to the published version of the manuscript.

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

**Acknowledgments:** We deeply thank all authors for their valuable contributions to this Special Issue, all reviewers for their thorough examination of these contributions and helpful recommendations, and the JMSE's editorial team for their outstanding support and professionalism.

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