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Sürdürülebilir Kalkınma Amaçları

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• MakaleAçık Erişim2026/r/gumushane/19384
  Yiğitler (tekman/erzurum) yöresindeki jeotermal ve soğuk su kaynaklarının hidrokimyasal özellikleri

  Kaygusuz, Abdullah; Vural, Alaaddin; Kaygusuz, Kamil; Sen, Ahmet Dundar; Çavuş, Dilek

  Bu çalışma, Erzurum-Tekman Yiğitler köyü civarındaki jeotermal, soğuk ve yüzey sularının hidrokimyasal özelliklerini, kökenini ve kullanım olanaklarını belirlemek amacıyla gerçekleştirilmiştir. İnceleme alanında jeotermal sistemin ana hazne kayacını peridotit ve gabro türü kayaçlardan oluşan Şahvelet Ofiyolitleri ile Kösehasan Formasyonu içindeki kireçtaşları, örtü kayacını ise masif yapıdaki Bingöldağı volkanitleri oluşturmaktadır. İncelenen jeotermal suların sıcaklık değerleri 43-49 °C, pH değerleri 7.03-8.33 ve EC değerleri 950-1550 µS/cm arasında değişmektedir. Analizler sonucunda, jeotermal, yeraltı ve yüzey sularının Ca-Mg-HCO₃ fasiyesinde olduğu belirlenmiştir. Piper, Schoeller ve Gibbs diyagramları ile yapılan sınıflandırmalar, aynı kaynaktan beslenen tek bir hidrokimyasal sistemin varlığına işaret etmektedir. (Ca+Mg)-(HCO₃+SO₄) diyagramı, Ca/Mg, HCO₃/SiO₂ ve Ca+Mg/HCO₃ oranları, CAI-I ve CAI-II indeksleri, kaya-su etkileşimine bağlı olarak su kimyasının genelde karbonat daha az oranda da silikat ayrışma süreçlerinden etkilendiğine işaret etmektedir. Hazne kaya sıcaklıkları silis jeotermometreleri ile 52-93°C, entalpi-silis karışım modeli ile 127-141°C hesaplanmıştır. Bu durum, akışkanın sığ seviyelerde %28-46 oranında soğuk yeraltı suları ile karıştığını göstermektedir. İçme suyu standartları açısından; soğuk kaynak suları uygun, yüzey suları ise sulama için elverişli bulunmuştur. Jeotermal sular; yüksek Ca, Fe, Mn, As ve NH4 derişimleri nedeniyle içme amaçlı kullanılamazken, kimyasal değerleri bakımından kaplıca kullanım potansiyeline sahiptir.

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• MakaleAçık Erişim2026/r/gumushane/12311
  GEOLOGY AND MINERAL CHEMISTRY OF THE ARSLANDEDE PLUTON IN THE EASTERN PONTIDES

  Güloğlu, Zikrullah Samet; Kaygusuz, Abdullah

  The Middle Eocene Arslandede Pluton, exposed in the Bayburt region on the southern margin of the Eastern Pontides (NE Turkey), has been investigated in terms of its geology and mineral chemistry. The pluton exhibits a NW-SE elongation and covers an area of approximately 7 km². It comprises a broad compositional spectrum ranging from monzodiorite to quartz monzonite. Major rock-forming minerals include plagioclase (An25-48), orthoclase (Or69-88), quartz, amphibole (Mg# = 0.63-0.73), biotite (Mg# = 0.52-0.62), pyroxene (Mg# = 0.70-0.75), and Fe-Ti oxides. Crystallization conditions, estimated via amphibole-plagioclase thermometry and Al-in-hornblende barometry, suggest crystallization temperatures of 737-812 °C and pressures of 0.09-1.61 kbar, corresponding to depths of 0.3-6.0 km. These results indicate that the pluton was emplaced at shallow crustal levels and subsequently solidified under low-pressure conditions. Comparison with other Middle Eocene plutons in the region reveals similar crystallization conditions, suggesting a common tectonic setting during the post-collisional extensional regime in the Eastern Pontides.

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• MakaleAçık Erişim2026/r/gumushane/12109
  Detrital zircon ages, Lu-Hf isotopes of zircon grains, Sr-Nd isotopes on whole rock and geochemistry of Campanian turbidites in the Eastern Pontides (NE Türkiye): A provenance assessment and Gondwana records

  Eker, Çiğdem Saydam; Yücel, Cem; Kaygusuz, Abdullah; Aydınçakır, Emre; Jeong, Youn-Joong; Yılmazer, Sinan; Sünnetçi, Kadir

  Detrital zircons are crucial stand-ins for the history of continental crust growth and disintegration, as well as the dispersal and assembly of supercontinents. Detrital zircons are effectively used to assess crustal history because sediments transport zircons from source rocks that are no longer at the surface. This study presents detailed Lu-Hf isotopic, U-Pb geochronological analyses of zircon, Sr-Nd isotopic analyses and whole-rock geochemical results from sandstone, volcanically derived sandstone and tuff samples of the Campanian-aged Bozbent Member in the Eastern Pontide Orogen belt of the Sakarya Zone. Sedimentological analyses show that the Bozbent Member was transported and deposited by turbidite currents, while petrographic and geochemical analyses show that the sandstones range from greywacke to litharenite. In this study, U-Pb ages of detrital zircon obtained from Campanian sandstones are presented, along with in situ εHf data. A magmatic origin is indicated by the majority of zircons' oscillatory zoning and by Th/U ratios ranging from 0.2 to 1.5. The ages of detrital zircons range from 2819 to 78 Ma, with most of these zircons being Proterozoic (552–994 Ma). Proterozoic zircons are detrital zircons associated with the Gondwana and the African Craton. The whole-rock geochemical data and Sr-Nd isotope compositions of the sandstones are consistent with local Carboniferous felsic plutons, Jurassic mafic and felsic plutons, Jurassic volcanic rocks, Jurassic clastic rocks and clastic material from Precambrian recycled sediments. It was calculated that more than 90% of the detrital zircons had crystallisation ages older than their depositional ages (CA-DA > 150 Ma, indicative of an extensional basin model). These findings indicate that the Campanian-aged Bozbent Member turbiditic sequence in the Eastern Pontides was deposited in an extensional fore-arc basin and therefore exhibits the petrographic and geochemical characteristics of passive margin sandstones.

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• MakaleAçık Erişim2025/r/gumushane/16733
  Mineral chemistry, thermodynamic evolution, and crystallization history of late miocene volcanic rocks around posof (Ardahan, Turkiye)

  Cicerali, Derya; Yücel, Cem; Aydinçakir, Emre; Kaygusuz, Abdullah

  This study aimed to constrain the crystallization and emplacement conditions of magmas that produced the Late Miocene volcanic rocks exposed at the junction of the Erzurum-Kars Plateau and the Eastern Pontides in the Northeastern Anatolia Region through a series of thermobarometric analyses. The volcanic succession unconformably overlies Oligocene mudstone, siltstone, and sandstone alternations, with limestone and cherty limestone at higher levels. Petrographically, they consist offine-to coarse-grained basalt, basaltic andesite, and andesite. Mineral compositions include plagioclase (An(16-77)), clinopyroxene (Wo(39-45)En(43-50)Fs(11-12)), orthopyroxene (Wo(3-4)En(73-82)Fs(14-24)), olivine (Fo(63-86)), hornblende (Mg#=0.62-0.79), and Fe-Ti oxides (Usp(0.05-1.44), Ilm(94.10-95.53)). The groundmass comprises microlites of these minerals and volcanic glass. The dominant textures are microlitic porphyritic, hyalomicrolitic, and microlitic porphyritic, while glomeroporphyritic, intergranular, pilotaxitic, subophitic, flow, and vesicular textures are also observed. Widely present disequilibrium features, such as zoning, sieve, and resorption, are common in plagioclase and clinopyroxene. Thermobarometric calculations indicate crystallization temperatures of 880-1230 degrees C, pressures of 0.73-8.71 kbar, oxygen fugacities between (-10.94) and (-8.92), and water contents of4.60-6.32 wt.%. These results suggest that the volcanic rocks crystallized under volatile-rich, oxidizing conditions across a broad depth range (similar to 2-32 km), at relatively high temperatures.

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• MakaleAçık Erişim2025/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.

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• MakaleAçık Erişim2025/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.

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• MakaleYalnız künye2025/r/gumushane/12396
  Concentrations, distribution, and source appointment of heavy metal/loids in non-clastic sedimentary rocks: a case study of early jurassic chert, northeastern türkiye

  Saydam Eker, Çiğdem; Kaygusuz, Abdullah; Arı, Uğur Volkan

  The Current study used geochemical indicators such as the geo-accumulation index (Igeo), the Enrichment Factor (EF), and the contamination factor (CF) to evaluate the regional distributions and accumulations of various heavy metal/loids (HM; Co, Mo, Pb, Zn, Cu, Ni, As, Cd) in early Jurassic cherts in the Gümüşhane (NE Türkiye). Five stratigraphic section measurement (MS) areas (Tedaş, Alemdar, Akçakale, Tekke, and Pirahmet) and one borehole (Eskibağlar well) were selected for sampling. Major and trace element compositions of the selected 25 samples were measured by inductively coupled plasma optical emission spectrometry (ICP-OES) and inductively coupled plasma mass spectrometry (ICP-MS). Calculated geochemical indexes indicated that Alemdar, Tekke MS, and Eskibağlar well samples were polluted with Pb, Zn, Cu, As, and Cd, Tedaş, Akçakale, and Pirahmet MS samples were polluted with Cd. Pearson's correlation coefficient (PCC) and principal component analysis (PCA) suggested that Zn, Pb, and Cu contaminating the Alemdar, Tekke MS, and Eskibağlar well samples were of ore mineralization origin, As was of terrigenous input, and Cd was probably of diatom origin. PCC and PCA showed that the Cd contaminating the Tedaş, Akçakale, and Pirahmet MS samples was probably of diatom origin, and the other metals found at normal levels in the samples were due to terrigenous input. The Early Jurassic period, which was a rift environment in the Gümüşhane region, is thought to have produced the cherts of the Alemdar, Tekke MS, and Eskibağlar well samples in a graben environment, while the cherts of the Tedaş, Akçakale, and Pirahmet MS were deposited in a horst environment. δU values, Ni/Co, and Vi/(V + Ni) ratios indicated that oxic-anoxic conditions were generally prevalent in the depositional environment, but redox conditions did not affect the abundance and distribution of HMs. These findings provide critical information for assessing heavy metal/loid enrichment and contamination potential not only in clastic sedimentary rocks, river sediments, and soils but also in non-clastic sedimentary rocks.

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• MakaleYalnız künye2025/r/gumushane/12314
  Origin and tectonic setting of the carbonate-hosted Kopuz Fe skarn Deposit, Sakarya Zone, NE Türkiye

  Sipahi, Ferkan; Akpınar, İbrahim; Gücer, Mehmet Ali; Kaygusuz, Abdullah; Vural, Alaaddin; Saydam Eker, Çiğdem

  The Kopuz Fe skarn deposit in the eastern Sakarya Zone is genetically associated with the 44–45 Ma Kopuz granitoid. The Fe ores are hosted within the contact zone between this granitoid and Jurassic Lower Cretaceous limestone. The deposit is characterized by both endo- and exoskarn zones, which exhibit a diverse range of minerals including clinopyroxene, plagioclase, amphibole, biotite, garnet, epidote, phlogopite, magnetite, hematite, pyrite, quartz, calcite, actinolite, limonite, and goethite. Magnetite and hematite, accompanied by small amounts of pyrite, are primarily ore minerals. Pyroxene types observed in the mineralization include diopsidic hedenbergite in the endoskarn zone and diopside in the exoskarn zone. Plagioclase in the endoskarn zone vary from oligoclase to Labrador in composition, which transition towards Na-rich plagioclase and orthoclase in the ore-bearing exoskarn zone. Amphiboles, primarily calcic in nature, are classified as Mg-hornblende and actinolite, with low F and Cl contents, indicating minimal F enrichment during Fe-skarn formation. Garnet is characterized by andradite in the exoskarn zone close to the endoskarn and grossular-andradite in the distal exoskarn zone. The increase of Ad/Gr ratios in zoned garnet indicate an increasing ƒO2 value outward from it. Considering that rare pyrite occur together with magnetite and hematite, we suggest that the deposit formed under conditions of low ƒS2 and high ƒO2 conditions. The homogenization temperature and salinity of the fluid inclusions in quartz from the exoskarn zone vary from 224 °C to 349 °C and 4.18 % (wt% NaCl equiv.), respectively. The oxygen isotope composition (5.10 ‰ to 7.86 ‰) of the fluids in equilibrium with magnetite and quartz minerals in the exoskarn zone supports a magmatic fluid origin. The oxygen isotopic signatures of epidote and amphibole further indicate a minor interaction with an additional source, likely meteoric waters. The sulfur isotope composition of pyrite (2.3 ‰) is consistent with a magmatic sulfur source. In summary, the middle Eocene-aged Kopuz Fe skarn deposit occurred a shallow depth within a magmatic arc, where oxidized conditions predominated.

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• MakaleYalnız künye2024/r/gumushane/14531
  Petrogenesis of Late Cretaceous A-type plutonic rocks from the Eastern Pontides Orogenic Belt (NE Turkey): constraints from zircon U-Pb geochronology, zircon Lu-Hf and whole-rock Sr-Nd-Pb-Hf isotopes

  Yücel, Cem; Aydınçakır, Emre; Kaygusuz, Abdullah; Arslan, Mehmet; Yi, Keewook; Jeong, Youn-Joong; Cicerali, Derya

  The Late Cretaceous magmatic history of the Eastern Pontides Orogenic Belt (NE Turkey) was generally characterized by common I-type and lesser A-type plutons in varying size and composition. Of these, A-type plutons from the Şebinkarahisar (Giresun) area yield SHRIMP zircon U-Pb age of 77.36 ± 0.96 Ma. The rocks of these plutons display a wide range of SiO2 contents (53.63 to 70.96 wt.%) and Mg-numbers (6.2–32.19) with A-type affinities characterized by enrichment in K2O and Na2O, Ga, Zr, and strong negative Eu anomalies. They also show arc-type petrochemical features including enrichment of large-ion lithophile elements (e.g. Cs, K, Rb) and light rare earth elements (LaN/LuN = 6.27–15.61), but depletion in high strength field elements (e.g. Nb, Ta, Ti, and P). The (87Sr/86Sr)i ratios and ɛNd(i) values of the studied rocks are in the range of 0.705129 to 0.0705347 and −3.64 to −3.12, respectively, while bulk rock ɛHf(i) values are between 1.86 and 4.36. They are characterized by positive zircon ɛHf(i) (1.74 to 10.88) plotting between the chondrite and depleted mantle evolutionary line values. Our data combined with the previous studies suggest that the magmas, that formed the Late Cretaceous plutons, were generated in an extensional tectonic environment due to slap roll-back and trench ward migration of the subduction zone to the south. The generation of hybrid magmas forming the studied plutons is in response to the melts derived from a metasomatized lithospheric mantle source, a relatively deeper mantle source, and the juvenile crust along with the heat transfer and decompression. Multi-sourced magmas rise through the continental crust and reach the final composition by predominantly fractional crystallization processes.

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• MakaleAçık Erişim2024/r/gumushane/14250
  U–Pb zircon dating, Sr-Nd whole-rock and Lu-Hf zircon isotope analyses of the Eocene Arslandede pluton, Eastern Pontides, NE Turkey: Implications for mantle source and magma evolution

  Kaygusuz, Abdullah; Güloğlu, Zikrullah Samet; Aydınçakır, Emre; Yücel, Cem; Vural, Alaaddin; Siebel, Wolfgang; Jeong, Youn-Joong

  The Eastern Pontide Orogenic Belt (EPOB) hosts numerous plutonic bodies with different dimensions, compositions and ages ranging from Paleozoic to Late Eocene in NE Turkey. U-Pb zircon dating suggests that the Arslandede pluton crystallized at 44.50 ± 0.29 Ma, corresponding to the Lutetian (Middle Eocene) period. Rocks of this pluton have monzonitic character, with compositions ranging from monzodiorite to granite (SiO2 = 49˗71 wt%). The studied monzonitic rocks have I-type, metaluminous and shoshonitic character and are enriched in large-ion lithophile elements (LILEs). The rare earth elements (REEs) have concave up shape (LaN/YbN = 6.64–11.57) and show negative to slightly positive Eu anomalies (EuN/Eu* = 0.37–1.24). 87Sr/86Sr(i) values of 0.704801–0.705102 and εNd(i) values of 1.01–1.34 correspond to the mantle series on isotope ratio diagrams. Positive εHf(i) values (5.01–14.91) plot between the depleted mantle and the chondritic evolution lines. The petrological features of the rocks from the Arslandede pluton show that fractional crystallization with low rates of assimilation and/or magma mixing were effective during crystallization. All data show that the magma source of the pluton derived from an enriched lithospheric mantle and emplaced into the crust after differentiation in a deep seated magma chamber contaminated by relatively small proportions of crustal rocks.

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