Yazarlar

• Kaygusuz, Abdullah(6)
• Aydınçakır, Emre(3)
• Gücer, Mehmet Ali(3)
• Yücel, Cem(3)
• Aydin, Faruk(2)
• Chen, Bin(2)
• Güloğlu, Zikrullah Samet(2)
• Karsli, Orhan(2)
• Şen, Cüneyt(2)
• Akaryall, Enver(1)
• Akaryalı, Enver(1)
• Arslan, Mehmet(1)
• Aslan, Zafer(1)
• Cicerali, Derya(1)
• Dokuz, Abdurrahman(1)
• Doruk, Cüneyt(1)
• Ilbeyli, Nurdane(1)
• Kandemir, Raif(1)
• Ruffet, Gilles(1)
• Satir, Muharrem(1)
• Saydam Eker, Çiğdem(1)
• Saydam Eker, Çiǧdem(1)
• Siebel, Wolfgang(1)
• Sipahi, Ferkan(1)
• Uysal, Ibrahim(1)
• Vural, Alaaddin(1)
• Wijbrans, Jan R.(1)
• Yi, Keewook(1)

• MakaleAçık Erişim2025Scopus SJRQ1/r/gumushane/14347
  Zircon U-Pb geochronology and Sr-Nd-Pb-Hf-O isotope signatures of Middle Eocene high-K plutons from the Eastern Pontides Orogenic Belt, NE Turkey: implications for parental magma sources and magmatic processes

  Kaygusuz, Abdullah; Güloğlu, Zikrullah Samet; Aydınçakır, Emre; Yücel, Cem; Vural, Alaaddin; Saydam Eker, Çiğdem; Cicerali, Derya

  The Eastern Pontides Orogenic Belt (EPOB) in northeastern Turkey is a well-preserved continental magmatic arc in the Alpine-Himalayan Orogenic Belt and contains many Eocene I-type high-K plutons. Employing LA-ICP-MS U-Pb zircon geochronology, the crystallization ages of the investigated Yaylalıköy and Taşbaşı plutons were established to be Lutetian (Middle Eocene), ranging from 47 Ma to 46 Ma. These plutons exhibit a compositional spectrum ranging from diorite to granodiorite, characterized by I-type, metaluminous, and high-K geochemical signatures. Notably, they are enriched in large-ion lithophile elements (LILEs) and light rare earth elements (LREEs), displaying pronounced negative Eu anomalies (EuN/Eu* = 0.58–0.96). Isotopic signatures reveal homogeneous and moderately low initial 87 Sr/86 Sr(i) ratios (0.704643–0.705034) and positive εNd(i) values (0.24 to 1.67) for the investigated plutons. These isotopic signatures are consistent with mantle origin, as evidenced by their position within the mantle array on isotope ratio diagrams. Lead isotope compositions exhibit limited variations, with initial ratios of 206 Pb/204 Pb(i) (18.55–18.64), 207 Pb/204 Pb(i) (15.61–15.64), and 208 Pb/204 Pb(i) (38.46–38.75). Zircon εHf(i) values are positive (2.32–6.20), plotting between the depleted mantle and chondritic evolution lines. Additionally, these rocks display low zircon δ18 O values (+4.54 to + 6.53‰), comparable to mantle composition. The petrographic characteristics of the investigated plutons suggest that fractional crystallization with minimal assimilation and/or magma mixing played a dominant role during their solidification. The integration of geochemical and isotopic data, alongside regional geological constraints, advocates for enriched lithospheric mantle as the source for the parental magmas of the studied plutons. These magmas subsequently underwent differentiation within a deep-seated magma chamber, followed by emplacement into the crust.

  AtıfScopus5·WoS6·OpenAlex6

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• MakaleAçık Erişim2025Scopus SJRQ2/r/gumushane/14069
  Petrochemistry and geochronology of Middle Eocene high-K calc-alkaline I-type Kazıkbeli pluton, NE Turkey: implications from zircon U-Pb ages and Sr-Nd-Pb-Lu-Hf isotope data

  Güloğlu, Zikrullah Samet; Kaygusuz, Abdullah

  The Kazıkbeli pluton, located in the Kürtün (Gümüşhane) region of the Eastern Pontides, NE Turkey, was studied by employing zircon U-Pb geochronology, whole-rock geochemistry, Sr-Nd-Pb and zircon Lu-Hf isotope geochemistry. LA-ICP-MS U-Pb zircon dating revealed that the gabbroic diorite and granodiorite components of the pluton solidified during the Lutetian epoch of the Middle Eocene, at approximately 46.10 ± 0.26 Ma and 45.37 ± 0.29 Ma, respectively. The pluton is composed of calc-alkaline rocks, ranging from gabbroic diorite to granite (SiO2 = 55.3 to 72.4 wt%). These I-type rocks are typically metaluminous but exhibit peraluminous tendencies in some cases. They are enriched in large ion lithophile elements and display concave chondrite-normalized rare earth element patterns (LaN/YbN = 4.39 to 6.67) with negative Eu anomalies (EuN/Eu* = 0.45 to 0.80). The initial εNd values ranged from 1.85 to 2.24, and the initial 87Sr/86Sr(i) ratios ranged from 0.70458 to 0.70484, consistent with a mantle source in the isotope ratio diagram. The initial 206Pb/204Pb(i), 207Pb/204Pb(i), and 208Pb/204Pb(i) ratios ranged from 18.505 to 18.571, 15.595 to 15.601, and 38.560 to 38.590, respectively. They have positive εHf(i) values (5.75 to 8.03), located between depleted mantle and chondrite evolution values. Fractional crystallization of plagioclase, hornblende, and Fe-Ti oxide minerals played a significant role in the magma evolution, while assimilation and magma mixing may have had a minor influence. Collectively, the evidence suggests that the primary magma source for these plutonic rocks was an enriched lithospheric mantle. Subsequent differentiation within crustal magma chambers, with limited crustal contamination, shaped the final magmatic evolution.

  AtıfScopus1·WoS1·OpenAlex2

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• MakaleYalnız künye2023Scopus SJRQ1/r/gumushane/12805
  The Sr, Nd, Pb and Hf isotopes and crystallization conditions of the middle Eocene Daǧdibi Pluton in the eastern Sakarya Zone, Turkey

  Sipahi, Ferkan; Gücer, Mehmet Ali; Dokuz, Abdurrahman; Yi, Keewook; Kaygusuz, Abdullah; Akaryall, Enver; Saydam Eker, Çiǧdem; Doruk, Cüneyt

  Magmatic activity in the Sakarya Zone, an important segment of the Alpine orogenic belt, continues intermittently from the middle Carboniferous to Miocene. In this study, we provide geochronological and geochemical data from the Daǧdibi Pluton in the eastern Sakarya Zone to present some inferences on the source region and petrogenesis of the middle Eocene magmatism. U-Pb zircon geochronology from two granodiorite samples gives middle Eocene ages of 44.75 ± 0.92 and 45.01 ± 0.59 Ma. The pluton is mainly composed of K-feldspar, plagioclase, quartz, Mg-hornblende/actinolite, Fe-Ti oxides and small amounts of biotite, and secondary chlorite and epidote. Parental magma of the intrusive rocks has a high-K calc-alkaline affinity with metaluminous character. The oxygen fugacity values vary between -18 and -17. The rocks show slightly radiogenic 87Sr/86Sr(i) (0.704845-0.705726) ratios and μNdi values between -0.96 and +0.52. Pb-Pb isotope ratios are typical for those of the lower continental crust. μHf(i) values of the zircons range from 0.14 to 10.26. The geochemical and isotopic features of the pluton point to a parental magma derived from a depleted mantle that was metasomatized by fluids during previous subduction events. The volumetric abundances of the rock types are decreased as the silica content increase, implying that the fractional crystallization is the most important process during the formation of the present compositional range of the pluton. Amphibole, plagioclase and Fe-Ti oxides are the fractionated phases while K-feldspar is largely accumulated. In the light of the data presented above, slab breakoff is regarded as the geodynamic process responsible for the formation of the Daǧdibi Pluton in the middle Eocene.

  AtıfScopus9·WoS7·OpenAlex10

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• MakaleAçık Erişim2022Scopus SJRQ2/r/gumushane/14533
  Petrogenesis of post-collisional Middle Eocene volcanism in the Eastern Pontides (NE, Turkey): Insights from geochemistry, whole-rock Sr-Nd-Pb isotopes, zircon U-Pb and 40Ar-39Ar geochronology

  Aydınçakır, Emre; Yücel, Cem; Ruffet, Gilles; Gücer, Mehmet Ali; Akaryalı, Enver; Kaygusuz, Abdullah

  The debate about whether Eocene magmatism is considered to be post-collisional or subduction-related or not still continues. Here we offer new 40Ar-39Ar ad U-Pb zircon geochronology, mineral chemistry, bulk rock and Sr-Nd-Pb isotope geochemistry data obtained from the southern dike (SD) suite, in comparison with the northern dike (ND) suite, from the Eastern Pontides. The geochronological data indicate that the SD suite erupted between 45.89 and 45.10 Ma corresponding to the Lutetian (Middle Eocene). The magmas of the ND suite are characterised by slightly more alkaline affinity compared to the SD suite. The trace and rare earth element (REEs) content of the SD suite is characterised by large ion lithophile element (LILEs; Sr, K2O, Ba, Rb) enrichment and depletion of Nb, Ta, and TiO2 elements to different degree with high Th/Yb ratios, which indicate that the magmas forming the SD and ND suites were derived from lithospheric mantle sources enriched by mostly slab-derived fluids in the spinel stability field. The Sr, Nd and Pb radiogenic isotope ratios of the dikes support the view that the magma for the hydrous group (H-SD) was derived from a relatively more enriched mantle source than the other SD and ND suites. The ND suite and the anhydrous group (A-SD) display similar geochemical features characterised by moderate light earth element (LREE)/heavy rare earth element (HREE) ratios, while the H-SD group has respectively lower LREE/HREE ratios indicating higher melting degree. Detailed considerations of the alkalinity, enrichment and partial melting degree for the source of the studied volcanic rocks indicate that the magmas of the northern dike suite are characterised by slightly more alkaline affinity, whereas the magmas throughout the southern dike suite show increments in the enrichment rate and melting degree. In light of the obtained data and comparative interpretations, the geodynamic evolution and differences in petrogenetic character of the Lutetian magmas from both the northern and southern parts of the Eastern Pontides may be explained by different degrees of melting of a net veined mantle source initially metasomatized by mostly subduction fluids during asthenospheric upwelling due to fragmented asymmetric delamination in a post-collisional extensional tectonic environment.

  AtıfScopus21·WoS20·OpenAlex22

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• MakaleYalnız künye2018Scopus SJRQ1/r/gumushane/15082
  Geochemical and Sr-Nd-Pb isotope characteristics of the Miocene to Pliocene volcanic rocks from the Kandilli (Erzurum) area, Eastern Anatolia (Turkey): Implications for magma evolution in extension-related origin

  Kaygusuz, Abdullah; Aslan, Zafer; Aydınçakır, Emre; Yücel, Cem; Gücer, Mehmet Ali; Şen, Cüneyt

  This paper presents Sr-Nd-Pb isotopic and whole-rock geochemical data of Miocene to Pliocene volcanic rocks in the Eastern Anatolia (Turkey) aiming to unravel their sources and evolutionary history. The wide compositional range of lavas and pyroclastics includes basaltic andesite, basaltic trachyandesite, trachyandesite, andesite and trachydacite. These calc-alkaline volcanics are enriched in large ion lithophile elements and light rare earth elements and depleted in the high field strength elements. Sr-Nd isotope data indicate low values for 87Sr/86Sr(i) (0.70432–0.70464) and high values for 143Nd/144Nd(i) (0.51272–0.51282). Further, these data are within the mantle array of the isotope ratio diagram. The lead (Pb) isotopic compositions (206Pb/204Pb(i) = 18.33 to 18.62, 207Pb/204Pb(i) = 15.51 to 15.60, 208Pb/204Pb(i) = 38.10 to 38.45) reveals the presence of an enriched source. The main petrological processes involved fractional crystallization and the mixing of at least two fractionated magmas having same source characteristics. All evidence supports the findings that the Kandilli volcanic rocks were derived from a partial melting of the both spinel and garnet bearing subcontinental lithospheric mantle, which had been previously metasomatized by mostly fluids derived from subducted slab during the collisional and post-collisional extension-related geodynamic setting in the Eastern Anatolia region of Turkey.

  AtıfScopus35·WoS31·OpenAlex35

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• MakaleYalnız künye2010Scopus SJRQ3/r/gumushane/15656
  Insight into magma genesis at convergent plate margins a case study from the eastern Pontides (NE Turkey)

  Kaygusuz, Abdullah; Siebel, Wolfgang; Ilbeyli, Nurdane; Arslan, Mehmet; Satir, Muharrem; Şen, Cüneyt

  Convergent plate margins are the most intense areas of granitoid magmatism on Earth. The Eastern Pontide Magmatic Belt in NE Turkey represents a paleo-arc with numerous quartz diorite to syenite intrusions, ranging in age from 142 to 56 Ma and being composed of K-feldspar, plagioclase, quartz, pyroxene, hornblende, biotite, and Fe-Ti oxides. The granitoids exhibit low- to high-K calc-alkaline, metaluminous to slightly peraluminous I-type features and contain abundant mafic magmatic enclaves (MME). They are characteristically enriched in large ion lithophile elements (LILE) and light rare earth elements (LREE) relative to high field strength elements (HFSE). Chondrite-normalized REE patterns are fractionated (LaN/LuN= 1.49-17.4) with pronounced negative Eu anomalies (Eu/Eu* = 0.46-1.77). Initial 87SrZ86Sr values are between 0.7056 and 0.7079, and εNd(1) values between -5.3 and 1.6. Fractional crystallization, magma mixing/mingling and crustal contamination played an important role during magma evolution. All these characteristics, combined with the low values of K2O/Na2O, Mg-number, ASI and ratios Of Al 2O3/ (FeOT+MgO+TiO2) and (Na 2O+K2O)/(FeOT+MgO+TiO2), suggest an origin by dehydration melting of mafic (amphibolitic) or tonalitic lower crustal source rocks.

  AtıfScopus54·WoS49·OpenAlex53

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• MakaleYalnız künye2008Scopus SJRQ1/r/gumushane/15802
  Petrogenesis of the Neogene alkaline volcanics with implications for post-collisional lithospheric thinning of the Eastern Pontides, NE Turkey

  Aydin, Faruk; Karsli, Orhan; Chen, Bin

  Whole-rock geochemistry, Sr-Nd-Pb isotopes and K-Ar data are reported for alkaline samples collected from the Neogene alkaline volcanics (NAVs) in the Eastern Pontides, northeastern Turkey, in order to investigate their source and petrogenesis and geodynamic evaluation of the region. The NAVs were made of three groups that comprise of basanite-tephrite (feldspar-free; Group A), tephrite-tephriphonolite (feldspar and feldspathoid-bearing; Group B) and alkaline basalt-rhyolite (feldspathoid-free; Group C) series. These rocks cover a broad compositional range from silica-undersaturated to silica-oversaturated types, almost all of which are potassic in character. They show enrichment of LREE and LILE and depletion of HFSE, without a Eu anomaly in most of the mafic samples. Textural features and calculated pressures based on the Cpx-barometer in each series indicate that the alkaline magma equilibrated at shallow crustal depths under a pressure of about 3-4.5 kbar and approximating a crystallization depth of 9-14 km. The NAVs are slightly depleted in isotopic composition, with respect to 87Sr/86Sr (ranging from 0.705018 to 0.705643) and 143Nd/144Nd (ranging from 0.512662 to 0.512714) that indicate young Nd model ages (0.51-059 Ga). This may indicate that the parent melts tapped a homogeneous and young lithospheric mantle source which was metasomatized by subduction-derived sediments during the Late Mesozoic. Pb isotopic compositions (206Pb/204Pb = 18.85-18.95; 207Pb/204Pb = 15.60-15.74; 208Pb/204Pb = 38.82-39.25) may also be consistent with a model for an enriched subcontinental lithospheric mantle source. Lithospheric thinning and resultant upwelling of asthenosphere induced by lithospheric delamination may have favoured partial melting of chemically enriched, young lithospheric mantle beneath the Eastern Pontides. Then, the melt subsequently underwent a fractional crystallization process along with or without minor amounts of crustal assimilation, generating a wide variety of rock types in a post-collision extensional regime in the Eastern Pontides during the Neogene.

  AtıfScopus131·OpenAlex137

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• MakaleYalnız künye2008Scopus SJRQ1/r/gumushane/15088
  Elemental and Sr-Nd-Pb isotopic geochemistry of the most recent Quaternary volcanism in the Erzincan Basin, Eastern Turkey: framework for the evaluation of basalt-lower crust interaction

  Karsli, Orhan; Chen, Bin; Uysal, Ibrahim; Aydin, Faruk; Wijbrans, Jan R.; Kandemir, Raif

  Whole-rock geochemical and Sr, Nd and Pb isotope data are presented for a representative suite of the Quaternary Erzincan Volcanics (QEV) from the Erzincan basin (EB) along the North Anatolian Fault Zone, aiming to understand their origin and implications for basalt-lower crust interaction. Unspiked K-Ar and 40Ar/39Ar dating of dome lavas from the QEVs yielded ages of 102 ± 2 to 1061 ± 88 ka. The QEVs range from high-K low silica trachy-andesite to rhyolite in composition, with rhyolite volumetrically the most abundant. All rocks show high-K calc-alkaline affinity, a geochemical signature common to many post-collisional magmas. They are characterized by enrichment in LILE (Rb, Ba, K, Th) and LREE ((La/Yb)CN = 3-33), with pronounced depletion of HFSE. All lavas show negligible or small negative Eu anomalies in the andesitic to dacitic and strong Eu anomalies in the rhyolitic samples. These rocks have relatively low 87Sr/86Sr = 0.70404-0.70587 and slightly depleted Nd isotopic compositions (εNd from - 0.9 to 2.8), with significantly varied Mg# ranging from 2 to 53. Pb isotopic compositions [206Pb/204Pb = 18.90-19.02, 207Pb/204Pb = 15.64-15.70, 208Pb/204Pb = 38.91-39.97] reveal an enriched source signature, which implies that some portions of metasomatized lithospheric mantle could have contributed to their genesis. The isotopic ratios and chemical features along with the textural and compositional disequilibrium of the plagioclases and amphiboles suggest that mixing of mafic and felsic magmas played an important role in the magma genesis. A possible scenario for the genesis of these volcanic rocks is that basaltic magma formed as a result of partial melting of a subcontinental lithospheric mantle source responding to a possible upwelling of asthenospheric mantle which was caused by the extension produced by strike-slip tectonics. Underplating of these high-temperature basaltic magmas sparked partial fusion of a juvenile lower continental crust producing felsic melts; then magma mixing between basaltic and the felsic magmas followed. Fractional crystallization, with minor amounts crustal contamination could have played an important role in the evolution of magma. Modelling based on Sr and Nd isotope data shows that less than 10% of a basic magma and about 90% of juvenile lower continental crustal material was involved in the generation of the QEVs in a pull-apart basin along the North Anatolian Fault Zone.

  AtıfScopus40·OpenAlex38

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