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Article

Major and Trace Element Compositions of Clinopyroxene Phenocrysts in Altered Basaltic Rocks from Yüksekova Complex within Bitlis Suture Zone (Elazığ, Eastern Turkey): Implications for the Tholeiitic to Calc-Alkaline Magmatism

by
Melek Ural
Department of Geological Engineering, Faculty of Engineering, Fırat University, 23119 Elazığ, Turkey
Minerals 2023, 13(2), 266; https://doi.org/10.3390/min13020266
Submission received: 25 December 2022 / Revised: 5 February 2023 / Accepted: 8 February 2023 / Published: 14 February 2023
(This article belongs to the Section Mineral Geochemistry and Geochronology)
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Abstract

:
This paper presents major and trace element compositions of the clinopyroxene phenocrysts from variably altered basaltic rocks from the Yüksekova Complex from E Anatolia (Elazığ) to reveal the geochemical affinity of the basaltic magmatism and the intensive parameters during magmatic crystallization. The Yüksekova Complex crops out over extensive areas to the north of the Bitlis suture. The investigated samples come from an area of ca. 2500 km2 in the Elazığ province. Petrographically, the basaltic rocks are represented by basalt, porphyric basalt and dolerite. The rocks are characterized by plagioclase, clinopyroxene, magnetite and ilmenite and are devoid of any hornblende and biotite, whereby clinopyroxene and plagioclase form phenocrysts. Generally, the groundmass is variably altered, whereas clinophenocrysts are comparatively fresh. The clinopyroxene is represented by the composition Wo37–48En43–53Fs4–17, with Mg/(Mg + Fe2+) ratios of 0.93–0.73. Compositionally, the clinopyroxenes resemble those from island arc tholeiitic, calc-alkaline and anorogenic tholeiitic rocks. Clinopyroxene-melt geothermobarometry yielded temperatures of 1146 and 1193 °C and pressures of 1.4 to 7.0 kbar, suggesting that the clinopyroxene phenocrysts started to grow at variable crustal depths. There is no apparent difference of magma temperatures between different magma affinities. The Fe–Mg partition coefficient between clinopyroxene and melt (KD Fe−MgCpx-Melt = 0.27) suggests that the parental magmas in equilibrium with clinopyroxene were mostly primitive, with Mg# of 65–79. The REE patterns of parental melts in equilibrium with clinopyroxene phenocrysts resemble those of low-K tholeiitic to middle- to high-K calc-alkaline rocks from the magmatic arcs. The results of this study are mostly consistent with the inferences from the whole-rock geochemistry, and indicate that the major and trace element geochemistry can be effectively used to infer the geochemical affinities of the highly altered basaltic rocks.

1. Introduction

Clinopyroxene forms early during the crystallization of mantle-derived magmas. Its composition shows dependence on magma composition and crystallization conditions [1,2,3,4,5]. In contrast to olivine and orthopyroxene, the trace-element compositions of clinopyroxenes can be easily measured in situ with required accuracy and precision by laser ablation inductively coupled mass spectrometer (LA-ICP-MS) and secondary ion mass spectrometer (SIMS). The partition coefficients of the trace elements between clinopyroxene and melt are known from both experimental and empirical studies [6,7,8,9]. Thus, the equilibrium magma composition can be calculated using the trace element composition of the clinopyroxene and the clinopyroxene-melts partition coefficients, especially in cumulate rocks and low-grade metamorphic and highly altered basaltic rocks with fresh relict clinopyroxene.
The southeast Anatolian orogenic belt (SEAOB), which is a part of the Alpine–Himalayan belt, was formed by the closure of the southern branch of Neotethys (Figure 1). The Yüksekova Complex (E Turkey) within the southeast Anatolian orogenic belt represents parts of an intraoceanic magmatic arc and interleaved ophiolitic mélanges of mainly the Late Cretaceous age [10,11,12]. This study deals with the geochemical features and origin of the basaltic rocks in the Yüksekova Complex. It presents electron microprobe major and laser ablation inductively coupled mass spectrometer trace element data on the clinopyroxenes from the variably altered basalts from the Yüksekova Complex and discusses these data on the geochemical characteristics of the magmas, from which these clinopyroxenes grew.

2. Geological Framework

Within the Tethyan realm, Turkey is made up of several continental blocks separated by sutures representing traces of former Neo-Tethyan oceanic domains (Figure 1). The Bitlis suture, also known as the southern branch of Neo-Tethys, separates the Arabian Platform from the Anatolide–Tauride Block, and is thought to represent the trace of an oceanic domain opened during the Triassic time [15,16,17,18]. The timing of the closure of the southern branch of Neo-Tethys is contentious. The estimates range from the Late Cretaceous to the Early Miocene [15,19,20]. A major ophiolite obduction onto the Arabian platform occurred by Maastrichtian onto the northern edge of the Arabian Platform, e.g., Kızıldağ (Hatay), Kermanshah and Oman [21].
The Bitlis suture is marked by fragments of supra-subduction-zone ophiolite, ophiolitic mélanges and local high-pressure metamorphic rocks [22,23,24,25,26,27]. To the north of the Bitlis suture, there are large metamorphic areas (Keban and Malatya), which represent the metamorphosed counterparts of the Paleozoic–Mesozoic rocks of the Anatolide–Tauride Block, and include greenschist- to amphibolite-facies metamorphic rocks (marble, mica schist, metaconglomerate and minor amphibolite). The timing of the metamorphism is constrained by Ar–Ar mica ages (85–80 Ma) as Late Cretaceous [28,29]. In addition, there are two elongated, large metamorphic areas, such as Pütürge and Bitlis massifs, mainly comprising greenschist- to amphibolite-facies metamorphic rocks, which probably represent the subducted northern margin of the Arabian Plate [22,25,27,28,30,31,32,33,34]. Ar–Ar mica dates are 71–74 Ma, pointing to the formation during the Campanian [22,25,35].
Along the Bitlis suture, ophiolites crop out along two distinct belts, such as (i) the southern belt ophiolites and (ii) the northern belt ophiolites [24,36,37]. The southern belt ophiolites are represented by the Hatay–Kızıldağ and Koçali ophiolites, which are obducted on the leading edge of the Arabian platform and display suprasubduction-zone affinities and a regular oceanic stratigraphy [36,38,39,40]. U–Pb, Ar–Ar and Sm–Nd dating suggests formation at 92–96 Ma (Cenomanian to Turonian, Late Cretaceous). The northern belt ophiolites are the Göksun, İspendere and Kömürhan ophiolites, which are attached to the Tauride active margin in the north and are significantly younger (84–88 Ma). The well-preserved oceanic-crustal remnants mainly exhibit an intact ophiolite pseudostratigraphy and are overlain by a volcanic–sedimentary unit made up of alternations of basic to acidic extrusive rocks, debris flows, volcaniclastic sandstones and pelagic limestones, which are interpreted as a tholeiitic, ensimatic, island arc assemblage built on the suprasubduction-zone type crust [36]. The Late Cretaceous ophiolitic mélanges include radiolarian cherts of Middle Triassic to Early Cretaceous age, suggesting the presence of an oceanic domain dating back to the Middle Triassic [17].

The Yüksekova Complex (YC)

The Late Cretaceous subduction and accretion complexes and parts of the intraoceanic arc along the Bitlis suture are commonly known under the name the Yüksekova Complex (the topic of this study) (Figure 1 and Figure 2). It includes blocks of basaltic pillow/massive lavas, shales, sandstone, pelagic limestone, radiolarite, basalt, gabbro, serpentinite and metamorphic rocks, as well as minor felsic to intermediate rocks (andesite, dacite, rhyodacite and rhyolite). This blocky formation is locally crosscut by dikes or sills of andesite, riodacite, tonalite and granodiorite [41]. Available geochemical data of the basic volcanic rocks display island-arc tholeiitic, calc-alkaline transitional, back-arc-basin affinities [12,41,42]. The ages of the radiolarites dated so far range from Cenomanian to Campanian [12,41,42,43]. Late Cenomanian to Maastrichtian ages were reported from micritic limestones within the complex [44,45]. Commonly, the Yüksekova Complex is interpreted as part of a Late Cretaceous intraoceanic magmatic arc [12,43]. On the geological maps, this accreted intraoceanic arc and ophiolitic mélanges are not differentiated.
In this study, I focus on the parts of the Yüksekova Complex exposed around the town Elazığ, over an area of ca. 2500 km2 (Figure 1, Figure 2 and Figure 3). To the east and south of Elazığ (north of the Hazar lake), the Yüksekova Complex is unconformably overlain by the Maastrichtian to Paleocene basal conglomerate and limestones of the Hazar Group [46]. Locally, the Yükseova Complex is overlain by Middle Eocene volcanic and clastic rocks of the Maden Complex [46,47]. To the north and northeast of Elazığ, the Yüksekova Complex is covered by various olistrostromal and chaotic formations (the Harami Formation, [48,49]) and bedded limestones and marls (the Kırkgeçit–Palu Formation [46]). In the N–NE of Elazığ, the YC consists of pillow lava, agglomerate, breccia and alternating volcanogenic sandstone-marl and red limestone from bottom to top. Locally, the unit is crosscut by plutonic or volcanic rocks (tonalite, dacite, etc.) and dolerite dykes [41]. The planktic foraminiferal ages obtained from micritic limestones are Maastrichtian [45]. All these field geological constraints suggest that the accretion of the intraoceanic arc occurred before the Maastrichtian time. In the S–SE of Elazığ (south of the Hazar lake), there is the YC, which consists of porous basaltic lavas that are interbedded with mudstone, micritic limestone and radiolarian cherty limestone. Chert bands have a thickness ranging from 10 to 140 cm and yield the Cenomanian to Campanian radiolarian age [43]. The basic lavas of YC are gray–burgundy–purple–green in color, with irregular pore-amygdale structures consisting of quartz, calcite and zeolite [50]. In this area, the YC is composed of three units from bottom to top [35], such as (i) low-grade metamorphic gabbro, dolerite and basalt; (ii) augite-bearing andesitic volcanic and volcaniclastic rocks metamorphosed in prehnite-pumpellyite facies; and (iii) andesitic volcanic and volcanoclastic rocks and pillow basalts crosscut by mafic to felsic dykes [35].
In the west of Elazığ, the unit was represented by massive or pillow lavas, several meters-thick agglomerate, volcanic breccia, volcanic sandstone, lithic tuff and micritic limestones. There are locally up to one-meter-thick chert interlayers of Santonian–Campanian age [43]. In the area, Kömürhan–İspendere ophiolites are thrust over the volcano-sedimentary rocks of YC. All the units are unconformably overlain by the olistostromal limestones of the Tertiary Seske Formation further west.

3. Analytical Techniques

Polished thin sections were prepared in the Vancouver Geotech laboratory in Canada. The major element compositions of clinopyroxenes were made using a JEOL JXA-8600 electron microprobe instrument equipped with four wavelength dispersive spectrometers (WDS) and integrated with an energy-dispersive spectrometer (EDS) system at the University of McGill (Montreal, QC, Canada). Operating conditions were 15 kV accelerating voltage, 20 nA beam current and 20 s counting time per each element. The beam diameter was ca. 1 μm. The following standards were used for calibration: jadeite for Na, garnet for Mg and Fe, titanite for Ca and Ti, chromite for Cr, rhodonite for Mn and adularia for K, Al and Si. Mineral formula calculations were done on the basis of six oxygen atoms and four cations. In total, 54 point analyses were carried out, and 14 of them are core and rim pairs (Figure S1a,b). The results of the electron microprobe analyses are given in Table 1 and Table S1.
The trace element compositions of clinopyroxenes were carried out with a laser ablation inductively coupled plasma mass spectrometer (LA-ICP-MS) using a NewWave 213 nm Nd-YAG laser-ablation system and a Thermo Finnigan iCapQ ICP-MS in the Department of Earth and Planetary Sciences at McGill University. The NIST 610 glass was used as a standard, and Si from the EMP analyses was used as the internal standard. The analyses were performed as line traverses, with a 10 Hz repetition rate, 20 μm beam diameter, scan speed of 15 μm/s and output rate of 45%. The estimated error was 5–10% for each element. Other parameters included: energy 40%, frequency 10 Hz, transects through pyroxenes 80 um thick and length depending on pyroxene inclusion. The pre-ablation step included cleaning of the surface. The standards analyzed were BCR2G at the beginning and end of each day of analyses (NIST610 2x after sample change and 1x prior to sample change, for each thin section). The results of the analysis are given in Table S2.

4. Results

4.1. Petrography

The petrographic features of the investigated samples are summarized in Table 2 and shown in Figure 4, as well as supplementary Figure S1a,b. The rocks are represented by basalt, porphyric basalt and dolerite. All the rock types comprise primarily clinopyroxene, plagioclase, rarely olivine and minor Fe-Ti oxide and are devoid of hornblende and biotite.
Basalts (PA1, TP1, MDN7 and MD12) display an aphyric texture, with local microphenocrysts of euhedral clinopyroxene and plagioclase set in a matrix consisting of plagioclase microliths and fine-grained clinopyroxene and Fe-Ti oxide (Figure 4a–c and Figure S1a). Microphenocrysts form clusters locally. Within the clinopyroxene, they are irregular domains that are interpreted as former melt inclusions. Optically determined plagioclase compositions range from An75 to An35. Secondary minerals, such as calcite, chlorite, sericite, albite and iron oxides, are common. However, microphenocrysts of clinopyroxene and plagioclase are replaced locally by chlorite and sericite, respectively. Plagioclase is altered locally to sericite and clay mineral (Table 2). However, the majority of microphenocrysts are still intact. Some basalts (e.g., PA1) show locally amygdaloidal features, whereby the vesicles (up to 2 mm across) are filled with chlorite and calcite (Figure 4 and Figure S1a,b).
Porphyric basalts (AY2, PM3, ALC3 and CB21) display a porphyric texture, characterized by phenocrysts of clinopyroxene, and rarely plagioclase, set in a matrix consisting of finer-grained plagioclase and clinopyroxene (Figure 4d,e and Figure S1a,b). Phenocrysts of euhedral to subhedral clinopyroxene locally contain inclusions of plagioclase, and oscillatory and sector zoning. Some clinopyroxene grains contain irregular skeletal domains, giving a sieve appearance. In relation to the aphyric basalts, they are less affected by alteration. The phenocrysts of plagioclase are characterized by An-richer compositions (An55-80), then finer-grained plagioclase in the groundmass (An55-30). Chlorite, calcite and sericite are common alteration minerals (Figure 4 and Figure S1a,b; Table 2). Calcite locally forms up to large grains, with a diameter of up to 3 mm in the matrix. The porphyric basalts are crosscut locally by up to 2 mm thick veinlets filled with calcite, chlorite and albite.
Dolerites are characterized by a subophitic texture and consist of clinopyroxene, plagioclase and Fe-Ti oxide (Figure 4g,h). Locally, large clinopyroxene grains contain large inclusions of plagioclase and Fe-Ti oxide. Secondary minerals are represented by calcite, chlorite, sericite, albite and titanite. Some dolerites (samples PM1, KR2 and PL5) show a texture characterized by the acicular intergrowth of clinopyroxene and plagioclase (An60-85), indicating rapid mineral growth, which probably represents a quench texture. The texture is shown only by samples that display anorogenic tholeiitic affinity (see below). Plagioclase and clinopyroxene grains are variably altered.

4.2. Major Element Composition of Clinopyroxene

The major element compositions of clinopyroxenes were measured in 14 basalt samples from the Yüksekova Complex and are given in Table 1 and Table S1. During the measurements, mainly phenocrysts of unaltered clinopyroxene were analyzed from 14 basalt samples. In total, 54 spot analyses were performed. The locations of the analyzed samples are shown in Figure 2.
Compositionally, the clinopyroxenes in all samples classify as augite to endiopside in the classification diagram after [51] (Figure 5). The clinopyroxenes are characterized by the compositional range Wo37–48En43–53Fs4–17. The XMg ratio [ = Mg/(Mg + Fe2+)] ratios of the clinopyroxene range from 0.93 to 0.73. The Fe3+ contents range from 0.029 to 0.109 cations, calculated on the basis of six oxygens and four cations. The Al concentrations range from 0.091 to 0.235 cpfu, whereby the highest values are shown by samples PL5, CVZ2 and KR2. The Na concentrations are in the range between 0.07 and 0.026 cpfu, and the highest values are shown by PL5, CVZ2 and KR2. The highest Ti concentrations (0.004–0.036 cpfu) are shown by samples PL5, CVZ2 and KR2. In contrast to the Ti, Al and Na concentrations, the Cr concentrations (0.000–0.028 cpfu) do not show any correlations with Ti, Al and Na. The clinopyroxenes with highest Ti, Al and Na concentrations fall into the non-orogenic field in the Ca vs Cr + Ti diagram after [1] (Figure 6a).
In some samples, clinopyroxenes display considerable compositional variation, whereby the intrasample variation of Mg/(Mg + Fe2+) can be as high as 0.15 to 0.17 as mole fraction (for example, samples PM3 and CB5). In the normally zoned clinopyroxenes, the cores of the clinopyroxene crystals vary from endiopside (Wo39–42En42–52Fs8–15) to augite at the rims (Wo41–45En41–44Fs10–16) (samples CB5, CB21 and MD-12). This suggests that the rims grew from more fractionated melts. On the other hand, some clinopyroxenes display the reverse compositional zoning, where the rims are characterized by higher Mg/(Mg + Fe2+) ratios (e.g., sample PM3). In some samples, the clinopyroxene displays no discernible zoning (sample TP-1).
In the Ca vs Cr + Ti diagram after [1] (Figure 6a), clinopyroxenes plot into both of the fields defined by the clinopyroxenes from orogenic and non-orogenic basalts. Clinopyroxenes from samples PL5, PM1 and KR2 plot mainly into the non-orogenic field. As pointed out above, the Ti, Al and Ca concentrations are higher than those in the other samples. In the Ca+Na versus Ti diagram, clinopyroxenes plot entirely into the tholeiitic to calc-alkaline fields (Figure 6b). In the diagram Al vs Ti, the clinopyroxenes plot mainly into the tholeiitic field (Figure 6c). To summarize, the clinopyroxenes mainly resemble those from orogenic tholeiitic to calc-alkaline rock (island arc tholeiites to calc-alkaline). Only samples PL5, KR2 and PM1 are from the basalts of non-orogenic (anorogenic) tholeiitic rocks. None of the clinopyroxenes are from alkaline rocks.

4.3. Trace Element Composition of Clinopyroxene

In total, 54 spot analyses of clinopyroxenes from 14 samples from the Yüksekova Complex were performed by LA-ICP-MS. The locations of the analyzed samples are shown in Figure 2, and their coordinates are given in Table S2. The trace element compositions of the analyzed clinopyroxenes are given in Table S2.
Overall, the clinopyroxenes show very low concentrations of Rb, Sr and Ba, and high concentrations of Sc and V (Table S2). On the chondrite-normalized, rare earth element patterns, clinopyroxenes are characterized mostly by concave-upward shapes (Figure 7a,b). The rare earth element compositions of the zoned clinopyroxene phenocrysts do not differ considerably (Figures S2 and S3). In some clinopyroxene phenocrysts, the rims have higher REE concentrations relative to the cores; in the others, vice versa. In normally zoned crystals, the cores display lower concentrations of rare earth elements, and in reversely zoned crystals, the cores display higher concentrations of rare earth elements.
Basalts can be differentiated into two groups based on the form of the REE pattern of clinopyroxene (Figure 7a). Type-I basalts (MDN7 and MDN12) have elevated light REE concentration and lower concentrations of heavy REE, with a slightly negative to absent Eu anomaly (La/YbCN = 0.55–1.20, Eu/Eu* = 0.82–1.08). On the other hand, type-II basalt (sample PA1) shows a slightly concave-upward shape, whereby the light REEs are significantly depleted relative to heavy REEs, while the middle REEs are hardly fractionated relative to the heavy ones (La/YbCN = 0.17–0.20; Eu/Eu*= 1.00–1.12; Gd/YbCN = 1.04–1.05). Sample TP1 shows a comparable REE pattern similar to PA1, but at significantly lower concentrations. On the multi-element variation diagrams, type-I basalts display consistently negative anomalies of Nb, Pb, Sr and Zr (Figure 8a). Type-II basalts, however, are devoid of the negative Sr anomaly. Sample TP1 differs from the other samples in the absence of negative anomalies of Sr and Zr, and the positive anomalies of Pb.
Porphyric basalts are differentiated into two groups based on the shape of the REE patterns of clinopyroxene phenocrysts similar to the basalts (Figure 7b). Type-I porphyric basalts (AY2 and CVZ2) display comparable shapes to those of the type-I basalts, and type II porphyric basalts (ALC3, CB21 and PM3) to type-II basalts. Clinopyroxenes from both type-I and type-II porphyric basalts display negative anomalies of Nb, Sr and Zr (Figure 8b). The Pb and Sr anomalies are not consistent, changing from negative to positive.
All the dolerite samples are characterized by strongly fractionated REE patterns, with a nearly absent Eu anomaly (Figure 7c). Similar to type-II basalts and porphyric basalts, light rare earth elements are strongly depleted with respect to middle and heavy rare earth elements (La/YbCN = 0.10–0.13, Eu/Eu* = 0.90–1.08, Gd/Ybcn = 1.03–1.41). On the primitive, mantle-normalized, multielement variation diagrams, the clinopyroxenes from porphyric basalts show the negative anomalies Sr and Zr (Figure 8c). However, the Nb and Pb anomalies are not consistent, probably due to poor counting statistics.
The anorogenic basalts display comparable REE patterns, similar to those of the dolerites and type-II basalt and porphyric basalts (La/YbCN = 0.09–0.29; Gd/YbCN = 1.12–1.40; Eu/Eu* = 0.68–1.15) (Figure 7d). On the primitive, mantle-normalized, multielement variation diagrams, the anorogenic basalts are characterized by negative anomalies of Pb, Sr and Zr, and the absence of a consistent negative Nb anomaly (Figure 8d). Only sample PM1 displays a negative Nb anomaly.

5. Discussion

5.1. Pressure-Temperature Estimates

In order to constrain the pressure and temperature conditions of clinopyroxene crystallization, we have applied the clinopyroxene-coexisting melt composition after [54,55]. For the coexisting melt composition, bulk rock composition was used. The results of the pressure-temperature estimates are given in Table 3. The calculated KD(Fe-Mg)cpx-liq values are between 0.25–0.30, which is totally within the range of the putative igneous equilibrium value (0.27 ± 0.03) [54].
The temperatures calculated by the formulation of [54] range from 1146 to 1193 °C (Table 3). On the other hand, temperatures calculated after [56] are roughly 100 °C lower than those after [54]. There is no considerable difference in the estimated temperatures among the different rock types. The estimated pressures after [54] are quite variable, ranging from 1.35 to 7.02 kbar. Generally, the pressure estimates for the clinopyroxenes in basalts and type-I porphyric basalts are significantly lower. However, pressure estimates after [57] are systematically low (0.70–1.87 kbar).
To sum up, clinopyroxenes from basic rocks in the Yuksekova Complex have crystallized from the magmas at temperatures of 1146 to 1193 °C and quite variable pressures (1.35 to 7.02 kbar). The variable pressure conditions suggest that the clinopyroxenes grew from magmas at different depths.

5.2. Parental Magma Compositions

The compositions of the parental magmas can be constrained based on the Fe–Mg partition coefficient between the melt and clinopyroxene, after [54]. On the basis of the Fe–Mg clinopyroxene–melt partition coefficient value of 0.27 (KD Fe-MgCpx-Melt = 0.27; [54]), the Mg# of the calculated parental melts in equilibrium with the clinopyroxene phenocrysts is given in Table 1, ranging from 41 to 73. Only samples CVZ2 and KR2 were probably derived from the fractionated mantle melts, as deduced by the relatively lower Mg#, 52–55 and 45–56, respectively. The clinopyroxenes in all the other samples grew from primitive mantle melts. The Mg# of the clinopyroxene phenocrysts in some samples shows a large variation. Thus, the Mg# of the calculated parental melts varies considerably (e.g., Mg#79–50 in sample PM3 and Mg#79–49 in sample TP1). This can be explained by the fact that some clinopyroxenes grew from primitive mantle melts and others by fractionated ones. On the other hand, the Mg# of the calculated parental melts is significantly different from that of the whole-rock Mg#. The whole-rock Mg# is between the calculated Mg# of the parental melts in equilibrium with clinopyroxene (Table S3).
The REE and trace element composition of the parental melts of the basaltic rocks in the Yüksekova Complex rocks can be calculated from the REE composition of the clinopyroxenes and the experimentally/empirically determined partition coefficients [6,8,9,58,59,60]. The rare earth patterns and multi-element variation diagrams of the calculated melts in equilibrium with clinopyroxenes are given in Figure 9 and Figure 10. Overall, the calculated REE patterns of the parental melts resemble those of the REE patterns of the whole rocks.
As stated above, the basalts are subdivided into two types, such as type-I and type-II. The calculated parental melts of type-I basalts (samples MDN7 and MD12) are characterized by relatively fractionated REE patterns (MDN7: La/YbCN = 9–11; MD12: La/YbCN = 4–7) and by the absence of any Eu anomaly (Figure 9a). In the multi-element variation diagrams, type-I basalts display a pronounced Nb anomaly (Figure 10a). With these geochemical features, they resemble calc-alkaline basalts. Unnormalized ratios (La/Yb = 6.5–15.7, Th/Yb = 5.2–13.0; [61]) are also characteristic of calc-alkaline basalts. The calculated parental melts of type-II basalts (samples PA1 and TP1) are characterized by slightly fractionated REE patterns (La/YbCN = 1–3) and show marked negative Nb, Sr and Zr anomalies in multi-element variation diagrams. In contrast to type-I basalts, type-II basalts resemble island-arc tholeiites compositionally.
Similar to basalts, porphyric basalts are subdivided into two types, such as type-I and type-II. The calculated primitive melts of type-I porphyric basalts (samples CVZ2 and AY2) in equilibrium with clinopyroxene phenocrysts are characterized by relatively fractionated REE patterns (La/YbCN = 4–6) with a negligible Eu anomaly (Eu/Eu* = 0.96–1.08) (Figure 9b). In the primitive, mantle-normalized, multi-element variation diagrams, they show a negative Nd anomaly (Figure 10b). Thus, type-I porphyric basalts were derived from primitive melts with calc-alkaline affinity. On the other hand, the parental magmas of the type-II porphyric basalts (samples ALC3, CB21 and PM3) in equilibrium with clinopyroxene are characterized by nearly flat REE patterns (La/YbCN = 0.83–2.22; Eu/Eu* = 0.89–1.20) (Figure 9b) and display marked negative Nb anomalies in multi-element variation diagrams (Figure 10b). Thus, they compositionally resemble island arc tholeiitic to transitional basalts.
Parental melts in equilibrium with the clinopyroxene from the dolerites (sample CB5 and SVC3) are characterized by the depletion of light REE and nearly flat middle to heavy REE (La/YbCN = 0.88–1.02; Gd/YbCN = 1.21–1.65), with an absent Eu/Eu* anomaly (Eu/Eu* = 0.89–1.07) (Figure 9c). In multi-element variation diagrams, the negative Nb anomaly is not consistent, ranging from marked to absent (Figure 10c). Thus, the dolerites resemble island-arc tholeiitic basalts.
Clinopyroxenes in anorogenic basalts (PM1 and PL5) grew from unfractionated mantle melts with Mg# 64–71. As pointed out above, sample KR2 is a product of relatively fractionated mantle melts (Mg#45–56) (Table 2). The REE pattern of the calculated parental melts in equilibrium with clinopyroxene phenocrysts are characterized by a nearly flat to slightly fractionated shape, with (La/Yb)CN = 0.76–2.36 and slightly negative to negligible Eu anomalies (Eu/Eu* = 0.68–1.14) (Figure 9d). In the multi-element variation diagrams normalized to the primitive mantle, the parental melts display no consistent negative Nb anomaly (Figure 10d). This is caused by the uncertainty in the measurements of Nb. Based on the major element compositions of the clinopyroxene, we suggest that the parental melts of the samples PM1, PL5 and KR2 were of anorogenic tholeiitic composition.

5.3. Sources of the Clinopyroxene Phenocrysts

Zoning in minerals implies a change in the intensive parameters, such as the pressure, temperature and magma composition during the time of crystal growth [62]. The clinopyroxenes in the basaltic rocks of the Yüksekova Complex display both normal and reverse zoning. Normal zoning would require a gradual or step-like compositional change in magma composition, specifically, a decrease of Mg and Cr and an increase of Mn and Ti. Reverse zoning, on the other hand, results from an influx of a more primitive magma into the magma chamber and resultant magma mixing [63,64,65], decompression during magma ascend [66] or more oxidizing conditions during later stages of crystallization [67,68].
Clinopyroxene phenocrysts from sample PM3 display both normal (C1-Px2a and C1-Px2b in Table S1) and strong reverse zoning (C2-Px4a and C2-Px4b in Table S1). Clinopyroxenes in the other samples are characterized by normal zoning from Mg-rich cores to Fe-rich rims. We tentatively ascribe the normal zoning to the progressive change of melt composition during fractionation and the reverse zoning to the magma injection of more primitive mantle magmas into the magma reservoir.

6. Conclusions

This study deals with the major and trace element compositions of clinopyroxene phenocrysts in the basaltic rocks of the Yüksekova Complex in E Anatolia to constrain the magma affinities and pressure and temperature conditions of magmatic crystallization. The basaltic rocks in the Yüksekova Complex are represented by basalt, porphyric basalt and dolerite. They consist of clinopyroxene, plagioclase and opaque minerals. The absence of phenocrysts of hydrous minerals, such as biotite and hornblende, is conspicuous. Although the groundmass of the rocks is highly altered, euhedral to subhedral clinopyroxene phenocrysts are relatively fresh. The sizes of the clinopyroxenes range from 0.1 mm to 15 mm. The major and trace element compositions of the clinopyroxene suggest that the Yüksekova basic rocks were derived from primitive mantle melts of tholeiitic to calc-alkaline affinity. The major element composition of some basalts points to anorogenic tholeiitic affinity. The REE patterns of parental melts in equilibrium with clinopyroxene phenocrysts resemble those of low-K tholeiitic to middle K calc-alkaline rocks from the intraoceanic arcs. The calculated magma temperatures based on clinopyroxene-melt geothermobarometry yielded magma temperatures in the range of 1146 and 1193 °C. There is no marked difference in magma temperatures between different magma affinities. The calculated pressures for the clinopyroxene phenocrysts range from 1.4 to 7.0 kbar, suggesting that the growth of the clinopyroxene phenocrysts occurred at variable depths, ranging from lower to upper continental crust. The results of this study are mostly consistent with the inferences from the whole-rock geochemistry, and they indicate that major and trace element geochemistry can be effectively used to infer the geochemical affinities of highly altered basaltic rocks.

Supplementary Materials

The following supporting information can be downloaded at: https://www.mdpi.com/article/10.3390/min13020266/s1, Figure S1a,b: Detailed microphotos of clinopyroxene phenocrys; Figure S2: Chondrite-normalized REE patterns of zoned clinopyroxene grains; Figure S3: Primitive mantle normalized multi-element variation patterns of zoned clinopyroxene grains; Table S1: Electron microprobe analyses of clinopyroxenes; Table S2: Trace element compositions of clinopyroxenes; Table S3: Calculated melt compositions in equilibrium with clinopyroxenes.

Funding

This research was funded by the Scientific and Technological Research Council of Turkey (TÜBİTAK #113Y314).

Data Availability Statement

Data supporting reported results are given in the paper and in the Supplementary Material.

Acknowledgments

I have benefited considerably from the constructive and thorough reviews by two anonymous referees. This study was financially supported by the Scientific and Technological Research Council of Turkey (TÜBİTAK, grant number 113Y314). I also thank Lang Shi for the microprobe analyses (Mcgill University, Montreal, QC, Canada).

Conflicts of Interest

The author declares no conflict of interest.

References

  1. Leterrier, J.; Maury, R.C.; Thonon, P.; Girard, D.; Marchal, M. Clinopyroxene composition as a method of identification of the magmatic affinities of paleo-volcanic series. Earth Planet. Sci. Lett. 1982, 59, 139–154. [Google Scholar] [CrossRef]
  2. Marks, M.; Halama, R.; Wenzel, T.; Markl, G. Trace element variations in clinopyroxene and amphibole from alkaline to peralkaline syenites and granites: Implications for mineral–melt trace-element partitioning. Chem. Geol. 2004, 211, 185–215. [Google Scholar] [CrossRef]
  3. Muravyeva, N.S.; Belyatsky, B.V.; Senin, V.G.; Ivanov, A.V. Sr–Nd–Pb isotope systematics and clinopyroxene-host disequilibrium in ultra-potassic magmas from Toro-Ankole and Virunga, East-African Rift: Implications for magma mixing and source heterogeneity. Lithos 2014, 210, 260–277. [Google Scholar] [CrossRef]
  4. Nisbet, E.G.; Pearce, J.A. Clinopyroxene Composition in Marie Lavas from Different Tectonic Settings. Contrib. Miner. Petrol. 1977, 63, 149–160. [Google Scholar] [CrossRef]
  5. Vannucci, R.; Rampone, E.; Picardo, G.B.; Ottolini, L.; Bottazzi, P. Ophiolitic magmatism in the Ligurian Tethys: An ion microprobe study of basaltic clinopyroxenes. Contrib. Mineral. Petrol. 1993, 115, 123–137. [Google Scholar] [CrossRef]
  6. Zack, T.; Foley, S.F.; Jenner, G.A. A consistent partition coefficient set for clinopyroxene, amphibole and garnet from laser ablation microprobe analysis of garnet pyroxenites from Kakanui, New Zealand. Neues Jahrb. Für Mineral. 1997, 172, 23–41. [Google Scholar] [CrossRef]
  7. Hill, E.; Blundy, J.D.; Wood, B.J. Clinopyroxene-melt trace element partitioning and the development of a predictive model for HFSE and Sc. Contrib. Mineral. Petrol. 2011, 161, 423–438. [Google Scholar] [CrossRef]
  8. Bédard, J.H. Parental magmas of the Nain Plutonic Suite anorthosites and mafic cumulates: A trace element modeling approach. Contrib. Mineral. Petrol. 2001, 141, 747–771. [Google Scholar] [CrossRef]
  9. Bédard, J.H. Parameterizations of calcic clinopyroxene—Melt trace element partition coefficients. Geochem. Geophys. Geosystems 2014, 15, 303–336. [Google Scholar] [CrossRef]
  10. Perincek, D. The Geology of Hazro-Korudag-Cüngüs-Maden-Ergani-Hazar-Elazığ-Malatya Area, Guide Book MTA, Ankara; 1979, 33p. Available online: https://www.researchgate.net/publication/291997458_The_Geology_of_Hazro-Korudag-Cungus-Maden-Ergani-Hazar-Elazig-_Malatya_area (accessed on 7 February 2023).
  11. Robertson, A.H.F.; Parlak, O.; Rızaoğlu, T.; Ünlügenç, U.C.; Inan, N.; Taslı, K.; Ustaömer, T. Tectonic evolution of the South Tethyan ocean: Evidence from the Eastern Taurus mountains (Elazığ region, SE Turkey). In Deformation of the Continental Crust: The Legacy of Mike Coward; Ries, A.C., Butler, R.W.H., Graham, R.H., Eds.; Geological Society: London, UK, 2007; Volume 272, pp. 233–272. [Google Scholar]
  12. Ural, M.; Arslan, M.; Göncüoğlu, M.C.; Tekin, U.K.; Kürüm, S. Late Cretaceous arc and back-arc formation within the Southern Neotethys: Whole-rock, trace element and Sr-Nd-Pb isotopic data from basaltic rocks of the Yüksekova Complex (Malatya-Elazığ, SE Turkey). Ofioliti 2015, 40, 57–72. [Google Scholar]
  13. MTA. 1/500.000 Scaled Geological Maps of Turkey. In General Directorate of Mineral Research and Exploration; Department of Geological Research of General Directorate of MTA: Ankara, Turkey, 2002. [Google Scholar]
  14. MTA. 1/100000 Scaled Geological Maps of Turkey. In General Directorate of Mineral Research and Exploration; Department of Geological Research of General Directorate of MTA: Ankara, Turkey, 2011. [Google Scholar]
  15. Şengör, A.M.C.; Yilmaz, Y. Tethyan evolution of Turkey: A plate tectonic approach. Tectonophysics 1981, 75, 181–241. [Google Scholar] [CrossRef]
  16. Göncüoğlu, M.C.; Turhan, N.; Tekin, U.K. Evidence for the Triassic rifting and opening of the Neotethyan Izmir-Ankara Ocean and discussion on the presence of Cimmerian events at the northern edge of the Tauride-Anatolide Platform, Turkey. Boll. Soc. Geol. Ital. 2003, 2, 203–212. [Google Scholar]
  17. Uzunçimen, S.; Tekin, U.K.; Bedi, Y.; Perincek, D.; Varol, E.; Soycan, H. Discovery of the late Triassic (Middle Carnian–Rhaetian) radiolarians in the volcanosedimentary sequences of the Kocali complex, SE Turkey: Correlation with the other Tauride units. J. Asian Earth Sci. 2011, 40, 180–200. [Google Scholar] [CrossRef]
  18. Akal, C.; Candan, O.; Koralay, O.E.; Oberhänsli, R.; Chen, F.; Prelević, D. Early Triassic potassic volcanism in the Afyon Zone of the Anatolides/Turkey: Implications for the rifting of the Neo-Tethys. Int. J. Earth Sci. 2012, 101, 177–194. [Google Scholar] [CrossRef]
  19. Agard, P.; Omrani, J.; Jolivet, L.; Mouthereau, F. Convergence history across Zagros (Iran): Constraints from collisional and earlier deformation. Int. J. Earth Sci. 2005, 94, 401–419. [Google Scholar] [CrossRef]
  20. Okay, A.I.; Zattin, M.; Cavazza, W. Apatite fission-track data for the Miocene Arabia-Eurasia collision. Geology 2010, 38, 35–38. [Google Scholar] [CrossRef]
  21. Jolivet, L.; Faccenna, C.; Agard, P.; Frizon de Lamotte, D.; Menant, A.; Sternai, P.; Guillocheau, F. Neo-Tethys geodynamics and mantle convection: From extension to compression in Africa and a conceptual model for obduction. Can. J. Earth Sci. 2016, 53, 1190–1204. [Google Scholar] [CrossRef]
  22. Göncüoğlu, M.C.; Turhan, N. Geology of the Bitlis metamorphic belt. In International Symposium on the Geology of the Taurus Belt; Tekeli, O., Göncüoğlu, M.C., Eds.; Proceedings: Ankara, Turkey, 1984; pp. 237–244. [Google Scholar]
  23. Robertson, A.H.F. Overview of the genesis and emplacement of Mesozoic ophiolites in the Eastern Mediterranean Tethyan region. Lithos 2002, 65, 1–67. [Google Scholar] [CrossRef]
  24. Dilek, Y.; Thy, P. Island arc tholeiite to boninitic melt evolution of the Cretaceous Kizildag (Turkey) ophiolite: Model for multi-stage early arc–forearc magmatism in Tethyan subduction factories. Lithos 2009, 113, 68–87. [Google Scholar] [CrossRef]
  25. Oberhänsli, R.; Candan, O.; Bousquet, R.; Rimmele, G.; Okay, A.; Goff, J. Alpine high pressure evolution of the eastern Bitlis complex, SE Turkey. Geol. Soc. Lond. Spec. Publ. 2010, 340, 461–483. [Google Scholar] [CrossRef]
  26. Oberhänsli, R.; Bousquet, R.; Candan, O.; Okay, A.I. Dating subduction events in east Anatolia, Turkey. Turk. J. Earth Sci. 2012, 21, 1–17. [Google Scholar]
  27. Oberhänsli, R.; Koralay, E.; Candan, O.; Pourteau, A.; Bousquet, R. Late Cretaceous eclogitic high-pressure relics in the Bitlis Massif. Geodin. Acta 2013, 26, 175–190. [Google Scholar] [CrossRef]
  28. Yazgan, E. Geodynamic evolution of the Eastern Taurus region. In The International Symposium on Geology of the Taurus Belt; Tekeli, O., Göncüoğlu, M.C., Eds.; MTA: Ankara, Turkey, 1984; pp. 199–208. [Google Scholar]
  29. Rolland, Y.; Perincek, D.; Kaymakci, N.; Sosson, M.; Barrier, E.; Avagyan, A. Evidence for∼ 80–75 Ma subduction jump during Anatolide–Tauride–Armenian block accretion and∼ 48 Ma Arabia–Eurasia collision in Lesser Caucasus–East Anatolia. J. Geodyn. 2012, 56–57, 76–85. [Google Scholar] [CrossRef]
  30. Göncüoğlu, M.C.; Turhan, N. New results on the age of Bitlis Metamorphics. Bull. Miner. Res. Explor. 1983, 95, 1–5. [Google Scholar]
  31. Göncüoğlu, M.C.; Turhan, N. Rock units and metamorphism of the basement and Lower Paleozoic cover of the Bitlis Metamorphic Complex, SE Turkey. In Lower Paleozoic Evolution in Northwest Gondwana; Göncüoğlu, M.C., Derman, A.S., Eds.; Turkish Association of Petroleum Geology: Ankara, Turkey, 1997; Volume 3, pp. 75–81. [Google Scholar]
  32. Yazgan, E.; Chessex, R. Geology and tectonic evolution of the southestern Taurides in the region of Malatya. Turk. Assoc. Petr. Geol. Bull. 1991, 3, 1–42. [Google Scholar]
  33. Bozkaya, O.; Yalcin, H.; Basibuyuk, Z.; Ozfirat, O.; Yilmaz, H. Origin and evolution of the southeast Anatolian metamorphic complex (Turkey). Geol. Carp. Bratisl. 2007, 58, 197. [Google Scholar]
  34. Topuz, G.; Candan, O.; Zack, T.; Yılmaz, A. East Anatolian plateau constructed over a continental basement: No evidence for the East Anatolian accretionary complex. Geology 2017, 45, 791–794. [Google Scholar] [CrossRef]
  35. Hempton, M. Structure and deformation history of the Bitlis suture near Lake Hazar, SE Turkey. Geol. Soc. Am. Bull. 1985, 96, 223–243. [Google Scholar] [CrossRef]
  36. Parlak, O.; Rızaoğlu, T.; Bağcı, U.; Karaoğlan, F.; Höck, V. Tectonic significance of the geochemistry and petrology of ophiolites in southeast Anatolia, Turkey. Tectonophysics 2009, 473, 173–187. [Google Scholar] [CrossRef]
  37. Karaoğlan, F.; Parlak, O.; Klötzli, U.; Thöni, M.; Koller, F. U–Pb and Sm–Nd geochronology of the ophiolites from the SE Turkey: Implications for the Neotethyan evolution. Geodin. Acta 2012, 25, 146–161. [Google Scholar] [CrossRef]
  38. Bağcı, U.; Parlak, O.; Höck, V. Geochemistry and tectonic environment of diverse magma generations forming the crustal units of the Kızıldağ (Hatay) ophiolite, Southern Turkey. Turk. J. Earth Sci. 2008, 17, 43–71. [Google Scholar]
  39. Parlak, O.; Karaoğlan, F.; Rizaoğlu, T.; Nurlu, N.; Bağci, U.; Höck, V.; Öztüfekçi-Önal, A.; Kürüm, S.; Topak, Y. Petrology of the İspendere (Malatya) ophiolite from the Southeast Anatolia: Implications for the Late Mesozoic evolution of the southern Neotethyan ocean. Geol. Soc. Lond. Spec. Publ. 2013, 372, 219–247. [Google Scholar] [CrossRef]
  40. Varol, E.; Bedi, Y.; Tekin, U.K.; Uzuncimen, S. Geochemical and Petrological characteristics of Late Triassic basic volcanic rocks from the Kocali complex; SE Turkey: Implications for the Triassic Evolution of Southern Tethys. Ofioliti 2011, 36, 101–115. [Google Scholar]
  41. Ural, M.; Sayit, K.; Koralay, O.E.; Goncuoglu, M.C. Geochemistry and Zircon U-Pb Dates of Felsic-Intermediate Members of the Late Cretaceous Yüksekova Arc Basin: Constraints on the Evolution of the Bitlis–Zagros Branch of Neotethys (Elazığ, E Turkey). Acta Geol. Sin. Engl. Ed. 2021, 95, 1199–1216. [Google Scholar] [CrossRef]
  42. Ural, M.; Sayit, K.; Tekin, U.K. Whole-rock and Nd-Pb isotope geochemistry and radiolarian ages of the volcanics from the Yüksekova Complex (Maden Area, Elazığ, E Turkey): Implıcatıons for a Late Cretaceous (Santonıan-Campanıan) back-arc basin in the southern Neotethys. Ofioliti 2022, 47, 65–83. [Google Scholar]
  43. Tekin, U.K.; Ural, M.; Göncüoğlu, M.C.; Arslan, M.; Kürüm, S. Upper Cretaceous Radiolarian ages from an arc–back-arc within the Yüksekova Complex in the southern Neotethys mélange, SE Turkey. Comptes. Rendus. Palevol. 2015, 14, 73–84. [Google Scholar] [CrossRef]
  44. Ural, M.; Sarı, B. New planktonic foraminifera data from the Upper Cretaceous pelagic limestones of the Yüksekova Complex in the Maden area (southeast of Elazığ, Eastern Turkey). In Proceedings of the IOP Conference Series: Earth and Environmental Science, The World Multidisciplinary Earth Sciences Symposium (WMESS), Prague, Czech Republic, 9–13 September 2019. [Google Scholar]
  45. Ural, M.; Kaya-Sarı, M. Paleogeographic and age findings on planktonic foraminiferal assemblages of Yüksekova Complex in the northeast of Elazig (Eastern Turkey). In Proceedings of the IOP Conference Series: Earth and Environmental Science 2019 (WMESS), Prague, Czech Republic, 9–13 September 2019. [Google Scholar]
  46. Çelik, H. The effects of linear coarse-grained slope channel bodies on the orientations of fold developments: A case study from the Middle Eocene-Lower Oligocene Kırkgeçit Formation, Elazığ, eastern Turkey. Turk. J. Earth Sci. 2013, 22, 320–338. [Google Scholar] [CrossRef]
  47. Yılmaz, Y.; Yigitbas, E.; Genc, S. Ophiolitic and metamorphic assemblages of southeast Anatolia and their significance in the geological evolution of the orogenic belt. Tectonics 1993, 12, 1280–1297. [Google Scholar] [CrossRef]
  48. Aksoy, E.; Türkmen, İ.; Turan, M.; Meriç, E. New findings on stratigraphic position and depositional environment of Harami Formation (Upper Campanian-Maastrichtian), South of Elazig. Bull. Turk. Assoc. Pet. Geol. 1999, 11, 1–15. [Google Scholar]
  49. İnceöz, M. Stratigraphy and depositional environments of Harami Formation (Upper Maastrichtian) in the north of Elazığ. Bull. Assoc. Turk. Pet. Geol. 1999, 8, 130–136. [Google Scholar]
  50. Ural, M.; Aktaş, M.A. Quantitative new findings about formation and origin of pillow lavas in the Yüksekova Arc Complex, Elazığ (Eastern Turkey). J. Fac. Eng. Archit. Gazi Univ. 2023, 38, 535–545. [Google Scholar]
  51. Morimoto, N. The Nomenclature of Pyroxenes. Mineral. Mag. 1988, 52, 425–433. [Google Scholar] [CrossRef]
  52. Boynton, W.V. Geochemistry of the rare earth elements: Meteorite studies. In Rare Earth Element Geochemistry; Henderson, P., Ed.; Elsevier: New York, NY, USA, 1984; pp. 63–114. [Google Scholar]
  53. Sun, S.S.; McDonough, W.F. Chemical and isotopic systematics of oceanic basalts: Implications for mantle composition and processes. Geol. Soc. Lond. Spec. Publ. 1989, 42, 313–345. [Google Scholar] [CrossRef]
  54. Putirka, K.D. Thermometers and barometers for volcanic systems. Rev. Mineral. Geochem. 2008, 69, 61–120. [Google Scholar] [CrossRef]
  55. Putirka, K. Clinopyroxene+ liquid equilibria to 100 kbar and 2450 K. Contrib. Mineral. Petrol. 1999, 135, 151–163. [Google Scholar] [CrossRef]
  56. Nimis, P.; Taylor, W.R. Single clinopyroxene thermobarometry for garnet peridotites. Part 1. Calibration and testing of a Cr-in-Cpx barometer and an enstatite-in-Cpx thermometer. Contrib. Mineral. Petrol. 2000, 139, 541–554. [Google Scholar] [CrossRef]
  57. Nimis, P.A. Clinopyroxene geobarometer for basaltic systems based on crystal-structure modeling. Contrib. Mineral. Petrol. 1995, 121, 115–125. [Google Scholar] [CrossRef]
  58. Jagoutz, O.; Müntener, O.; Ulmer, P.; Pettke, T.; Burg, J.P.; Dawood, H.; Hussain, S. Petrology and mineral chemistry of lower crustal intrusions: The Chilas Complex, Kohistan (NW Pakistan). J. Petrol. 2007, 48, 1895–1953. [Google Scholar] [CrossRef]
  59. Tribuzio, R.; Tiepolo, M.; Fiameni, S. A mafic-ultramafic cumulate sequence derived from boninite-type melts (Niagara Icefalls, northern Victoria Land, Antarctica). Contrib. Mineral. Petrol. 2008, 155, 619–633. [Google Scholar] [CrossRef]
  60. Topuz, G.; Altherr, R.; Candan, O.; Wang, J.M.; Okay, A.I.; Wu, F.Y.; Ergen, A.; Zack, T.; Siebel, W.; Shangh, C.K.; et al. Carboniferous mafic-ultramafic intrusions in the Eastern Pontides (Pulur complex): Implications for the source of coeval voluminous granites. Lithos 2023, 436–437, 106946. [Google Scholar] [CrossRef]
  61. Ross, P.S.; Bédard, J.H. Magmatic affinity of modern and ancient subalkaline volcanic rocks determined from trace-element discriminant diagrams. Can. J. Earth Sci. 2009, 46, 823–839. [Google Scholar] [CrossRef]
  62. Shore, M.; Fowler, A.D. Oscillatory zoning in minerals; a common phenomenon. Can. Mineral. 1996, 34, 1111–1126. [Google Scholar]
  63. Streck, M.J. Mineral Textures and zoning as evidence for open system processes. Rev. Mineral. Geochem. 2008, 69, 595–622. [Google Scholar] [CrossRef]
  64. Nixon, G.T.; Pearce, T.H. Laser-interferometry of oscillatory zoning in plagioclase: The record of magma mixing and phenocryst recycling in calc-alkaline magma chambers, Iztaccihuat Volcano, Mexico. Am. Mineral. 1987, 72, 1144–1162. [Google Scholar]
  65. Aldanmaz, E. Mineral-chemical constraints on the Miocene calc-alkaline and shoshonitic volcanic rocks of western Turkey: Disequilibrium phenocryst assemblages as indicators of magma storage and mixing conditions. Turk. J. Earth Sci. 2006, 15, 47–73. [Google Scholar]
  66. Kontak, D.J.; Clark, A.H.; Pearce, T.H. Recognition of simple and complex zoning in olivine and orthopyroxene phenocrysts using laser interference microscopy. Mineral. Mag. 1984, 48, 547–550. [Google Scholar] [CrossRef]
  67. Luhr, J.F.; Carmichael, S.E. The Colima volcanic complex, Mexico i. Post-caldera andesites from Colima volcano. Contrib. Mineral. Petrol. 1980, 71, 343–372. [Google Scholar] [CrossRef]
  68. Grunder, A.L.; Mahood, G.A. Physical and chemical models of zoned silicic magmas: The Loma Seca Tuff and Calabozos caldera, southern Andes. J. Petrol. 1988, 29, 831–867. [Google Scholar] [CrossRef]
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Figure 1. Distribution of the ophiolites, ophiolitic mélanges and various metamorphic areas along the Bitlis suture (modified after [13,14]).
Figure 1. Distribution of the ophiolites, ophiolitic mélanges and various metamorphic areas along the Bitlis suture (modified after [13,14]).
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Figure 2. Geological map of the Elazığ region together with the locations of the studied samples in this study (modified after [12,13]).
Figure 2. Geological map of the Elazığ region together with the locations of the studied samples in this study (modified after [12,13]).
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Figure 3. Field pictures of the Yüksekova Complex, showing the outcrops where the investigated samples were taken from the Elazığ area.
Figure 3. Field pictures of the Yüksekova Complex, showing the outcrops where the investigated samples were taken from the Elazığ area.
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Figure 4. Microphotographs of mineralogical and textural characteristics of the investigated samples from the Yüksekova Complex. (a) Basalt (BA, sample MD-12); (b) Basalt (BA, sample MDN-7); (c) Basalt (BA, sample TP-1); (d) Porphyric basalt (PBA, sample PM-3); (e) Porphyric basalt (PBA, sample AY-2); (f) Dolerite (DO, sample ÇB-5); (g) Anorogenic basalt (ABA, sample PM-1), (h) Anorogenic basalt (ABA, sample PL-5)). Cpx: clinopyroxene, pl: plagioclase.
Figure 4. Microphotographs of mineralogical and textural characteristics of the investigated samples from the Yüksekova Complex. (a) Basalt (BA, sample MD-12); (b) Basalt (BA, sample MDN-7); (c) Basalt (BA, sample TP-1); (d) Porphyric basalt (PBA, sample PM-3); (e) Porphyric basalt (PBA, sample AY-2); (f) Dolerite (DO, sample ÇB-5); (g) Anorogenic basalt (ABA, sample PM-1), (h) Anorogenic basalt (ABA, sample PL-5)). Cpx: clinopyroxene, pl: plagioclase.
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Figure 5. Compositional variation of clinopyroxene phenocrysts in the Yüksekova Complex in Wo-En-Fs triangle, after [51].
Figure 5. Compositional variation of clinopyroxene phenocrysts in the Yüksekova Complex in Wo-En-Fs triangle, after [51].
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Figure 6. Compositional variation of the clinopyroxene phenocrysts in (a) Ca vs. Ti + Cr, (b) Ca + Na vs. Ti, and (c) Al vs. Ti diagrams after [1]. Identification of magmatic affinities based on the major and minor element composition of clinopyroxene phenocrysts from the Yüksekova Complex.
Figure 6. Compositional variation of the clinopyroxene phenocrysts in (a) Ca vs. Ti + Cr, (b) Ca + Na vs. Ti, and (c) Al vs. Ti diagrams after [1]. Identification of magmatic affinities based on the major and minor element composition of clinopyroxene phenocrysts from the Yüksekova Complex.
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Figure 7. Chondrite-normalized rare earth element patterns of the clinopyroxene phenocrysts from the Yüksekova Complex (Normalizing values are from [52]). (a) Basalts; (b) Porphyric basalts; (c) Dolerites; (d) Anorogenic basalts.
Figure 7. Chondrite-normalized rare earth element patterns of the clinopyroxene phenocrysts from the Yüksekova Complex (Normalizing values are from [52]). (a) Basalts; (b) Porphyric basalts; (c) Dolerites; (d) Anorogenic basalts.
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Figure 8. Primitive mantle-normalized multi-element variation diagrams of the clinopyroxene phenocrysts from the Yüksekova Complex (Normalizing values are from [53]). (a) Basalts; (b) Porphyric basalts; (c) Dolerites; (d) Anorogenic basalts.
Figure 8. Primitive mantle-normalized multi-element variation diagrams of the clinopyroxene phenocrysts from the Yüksekova Complex (Normalizing values are from [53]). (a) Basalts; (b) Porphyric basalts; (c) Dolerites; (d) Anorogenic basalts.
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Figure 9. Calculated REE patterns of the parental melt in equilibrium with clinopyroxene phenocrysts from the Yüksekova Complex. For comparison, REE patterns of low-K tholeiitic (orange), middle (blue) and high-K calc-alkaline rocks (red) are also shown (taken from [60] and the references therein); please see ‘9a’ for legend. (a) Basalts; (b) Porphyric basalts; (c) Dolerites; (d) Anorogenic basalts.
Figure 9. Calculated REE patterns of the parental melt in equilibrium with clinopyroxene phenocrysts from the Yüksekova Complex. For comparison, REE patterns of low-K tholeiitic (orange), middle (blue) and high-K calc-alkaline rocks (red) are also shown (taken from [60] and the references therein); please see ‘9a’ for legend. (a) Basalts; (b) Porphyric basalts; (c) Dolerites; (d) Anorogenic basalts.
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Figure 10. Calculated multi-element variation patterns of the parental melt in equilibrium with clinopyroxene phenocrysts from the Yüksekova Complex. (a) Basalts; (b) Porphyric basalts; (c) Dolerites; (d) Anorogenic basalts.
Figure 10. Calculated multi-element variation patterns of the parental melt in equilibrium with clinopyroxene phenocrysts from the Yüksekova Complex. (a) Basalts; (b) Porphyric basalts; (c) Dolerites; (d) Anorogenic basalts.
Minerals 13 00266 g010
Table
Table 1. Selected representative electron microprobe analyses of clinopyroxene from the different basic rocks from the Yüksekova Complex (E Anatolia).
Table 1. Selected representative electron microprobe analyses of clinopyroxene from the different basic rocks from the Yüksekova Complex (E Anatolia).
Sample Rock Setting MDN7MD12TP1TP1CVZ2AY2AY2ALC3CB21PM3CB5CB5SVC3PL5KR2PM1
BABABABAPBAPBAPBAPBAPBAPBADODODOABAABAABA
CoreRimCoreRimCoreCoreRimCoreCoreCoreCoreRimCoreCoreCoreCore
Weight %
SiO253.3351.2553.6052.3150.1049.7352.2050.2251.5852.2652.3049.5551.2549.5549.8553.01
TiO20.180.490.140.200.870.560.390.850.380.210.391.120.591.061.280.35
Al2O31.723.661.683.013.444.642.564.303.873.131.803.283.385.403.831.90
Cr2O30.280.380.250.240.010.530.200.510.800.650.170.020.460.720.090.49
FeOt5.265.663.655.018.746.175.846.004.553.926.5012.696.036.149.185.31
MnO0.180.150.110.130.320.130.180.150.110.120.190.350.160.140.200.17
MgO19.1916.5017.9917.0915.2115.3117.0716.0717.7617.8017.4215.0816.7815.5114.7718.77
CaO19.4321.5022.5221.5619.9222.0821.3821.0920.4821.5920.5016.8820.7020.8420.1919.67
Na2O0.110.190.140.200.370.210.140.240.250.170.210.290.270.320.290.19
K2O0.010.020.020.020.020.020.020.020.010.020.010.020.020.020.010.01
Total99.6799.79100.0899.7699.0099.3799.9899.4699.7899.8599.4999.2899.6599.7099.7099.87
Cations based on 6 oxygens and 4 cations
Si1.9411.8791.9451.9111.8701.8381.9091.8511.8781.9001.9231.8641.8811.8251.8551.929
Ti0.0050.0140.0040.0060.0250.0160.0110.0240.0100.0060.0110.0320.0160.0290.0360.009
Al0.0740.1580.0720.1290.1520.2020.1100.1870.1660.1340.0780.1460.1460.2350.1680.082
Cr0.0080.0110.0070.0070.0000.0160.0060.0150.0230.0190.0050.0010.0130.0210.0030.014
Fe3+0.0340.0610.0350.0440.0860.0900.0540.0670.0520.0480.0650.0840.0650.0600.0690.041
Fe2+0.1260.1130.0760.1090.1870.1010.1250.1180.0870.0710.1350.3150.1200.1290.2160.120
Mn0.0050.0050.0030.0040.0100.0040.0050.0050.0030.0040.0060.0110.0050.0040.0060.005
Mg1.0410.9020.9730.9310.8460.8440.9310.8830.9640.9650.9550.8460.9180.8510.8201.018
Ca0.7580.8450.8750.8440.7970.8740.8380.8330.7990.8410.8080.6800.8140.8220.8050.767
Na0.0080.0140.0100.0140.0260.0150.0100.0170.0170.0120.0150.0210.0190.0230.0210.013
K0.0000.0010.0010.0010.0010.0010.0010.0010.0000.0010.0000.0010.0010.0010.0000.000
Mg#0.890.890.930.900.820.890.880.880.920.930.880.730.880.870.790.89
Mg# melt *0.690.690.780.700.550.700.670.670.750.790.660.420.680.640.510.70
BA: Basalt, PBA: Porphyric basalt, DO: Dolerite, ABA: Anorogenic basalt; * Mg# of melt assumes a KD(cpx-liq)(Fe-Mg) of 0.272.
Table
Table 2. Microtextural features and mineralogic constituents of the different basic rocks from the Yüksekova Complex (E Anatolia).
Table 2. Microtextural features and mineralogic constituents of the different basic rocks from the Yüksekova Complex (E Anatolia).
SampleCoordinates (UTM)TextureMineralsAlteration
Basalt
MD1237S560825
4253261		aphyricPl + Cpx + Ol + Opcalcite, chlorite, sericite
MDN737S553439
4257519		aphyricPl + Cpx + Opcalcite, chlorite, sericite
PA137S580292
4283765		aphyricPl + Cpx + Opcalcite, chlorite, sericite, clay
TP137S498550
4259330		aphyricPl + Cpxcalcite, chlorite, sericite, clay
Porphyric basalt
ALC337S522903
4257144		porphyricPl + Cpx + Opcalcite, chlorite, sericite, clay
AY237S536505
4271335		porphyricPl + Cpxcalcite, chlorite, sericite, clay
CB2137S548988
4288191		porphyricPl + Cpxcalcite, chlorite, sericite, clay
CVZ237S532173
4262311		porphyricPl + Cpx + Opcalcite, chlorite, sericite, clay
KR237S456350
4221784		porphyricPl + Cpx + Opcalcite, chlorite, sericite
PM337S555140
4277462		porphyricPl + Cpxcalcite, chlorite, sericite
Dolerite
CB537S552281
4289953		subophiticPl + Cpx + Opcalcite, chlorite, sericite
SVC337S521987subophiticPl + Cpx + Opcalcite, chlorite
4254380
Anorogenic basalts
PL537S461316
4230366		porphyricPl + Cpx + Opcalcite, chlorite, sericite, epidote
KR237S456350aphyricPl + Cpx + Opcalcite, chlorite
4221784
PM137S555023
4277561		subophiticPl + Cpx + Opcalcite, chlorite, sericite, epidote
Table
Table 3. Estimates of the crystallization conditions of clinopyroxenes from the Yüksekova Complex (E Anatolia).
Table 3. Estimates of the crystallization conditions of clinopyroxenes from the Yüksekova Complex (E Anatolia).
P kbar 1T °C 1P kbar 2T °C 2P kbar 3T °C 4
Basalt
MD12-37a type-I0.401180 11630.051086
MD12-37b type-I2.1311730.4611670.98991
MD12-38a type-I2.8811741.0611740.91997
MDN7-40a type-I0.3811980.9212140.701158
MDN7-41a type-I0.3611900.3812070.411134
MDN7-42a type-I3.4712072.9612261.641027
MDN7-43a type-I1.8012172.8912250.841087
PA1-19atype-II0.101167 1173 1067
PA1-20atype-II 1162 1173 1105
TP1-34a 0.9211440.3410260.24980
TP1-35a 1132 1019 954
TP1-35b 2.2911481.3110361.111001
TP1-36a 2.0911232.251042 978
Porphyric basalt
AY2-10atype-I1.961150 11751.07898
AY2-11atype-I 1167 11711.27943
AY2-12atype-I1.431149 11730.12909
AY2-12btype-I 1146 1155 1010
ALC3-24atype-II8.89123211.5312330.281159
ALC3-25atype-II12.29124214.1312491.421042
ALC3-26atype-II13.25123614.3112501.421006
ALC3-27atype-II9.17123211.761232 1137
CB21-16atype-II 1192 11663.101080
CB21-17atype-II 1186 11611.641094
CB21-18atype-II 1172 11671.531041
CB21-19atype-II 1166 1154 1094
CVZ2-28atype-II
CVZ2-29atype-II
PM3-1atype-II5.4811813.8411770.94963
PM3-2atype-II5.0111963.5211771.871029
PM3-2btype-II3.6211762.2111650.681031
PM3-3atype-II3.4511862.6011680.891050
PM3-4atype-II9.2911797.091212 1009
PM3-4btype-II3.6311672.401167 1047
PM3-5atype-II6.7011755.511191 977
PM3-5btype-II3.4611661.711165 1087
Dolerite
CB5-13a 2.0611780.521196 1108
CB5-14a 5.1311872.0312061.77998
CB5-15a 1.8911710.241189 1054
CB5-15b 6.6811593.781238 1096
SVC3-21a 8.83120410.1211300.051073
SVC3-22a 8.9011969.5811270.171064
SVC3-23a 9.8611969.7111281.011035
Anorogenic basalt
PL5-47a 11.0312009.8311842.86996
PL5-48a 11.2612039.8611852.851006
PL5-49a 10.0812079.7711822.711019
KR2-30a 5.5911723.811225 998
KR2-31a 4.9911804.511231 1014
KR2-32a 6.8611814.3212290.94955
KR2-33a 6.5811794.571230 960
PM1-6a 5.5811872.0611922.361055
PM1-7a 5.8911672.0511860.92967
PM1-8a 1.8111890.1911740.671129
PM1-9a 4.6311841.5011821.821007
1 [54], equations 32C and 32D; 2 [55]; 3 [57]; 4 [56].
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Ural, M. Major and Trace Element Compositions of Clinopyroxene Phenocrysts in Altered Basaltic Rocks from Yüksekova Complex within Bitlis Suture Zone (Elazığ, Eastern Turkey): Implications for the Tholeiitic to Calc-Alkaline Magmatism. Minerals 2023, 13, 266. https://doi.org/10.3390/min13020266

AMA Style

Ural M. Major and Trace Element Compositions of Clinopyroxene Phenocrysts in Altered Basaltic Rocks from Yüksekova Complex within Bitlis Suture Zone (Elazığ, Eastern Turkey): Implications for the Tholeiitic to Calc-Alkaline Magmatism. Minerals. 2023; 13(2):266. https://doi.org/10.3390/min13020266

Chicago/Turabian Style

Ural, Melek. 2023. "Major and Trace Element Compositions of Clinopyroxene Phenocrysts in Altered Basaltic Rocks from Yüksekova Complex within Bitlis Suture Zone (Elazığ, Eastern Turkey): Implications for the Tholeiitic to Calc-Alkaline Magmatism" Minerals 13, no. 2: 266. https://doi.org/10.3390/min13020266

APA Style

Ural, M. (2023). Major and Trace Element Compositions of Clinopyroxene Phenocrysts in Altered Basaltic Rocks from Yüksekova Complex within Bitlis Suture Zone (Elazığ, Eastern Turkey): Implications for the Tholeiitic to Calc-Alkaline Magmatism. Minerals, 13(2), 266. https://doi.org/10.3390/min13020266

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