Yazarlar
- Kaygusuz, Abdullah(8)
- Yücel, Cem(5)
- Aydinçakir, Emre(4)
- Sipahi, Ferkan(4)
- Arslan, Mehmet(2)
- Aslan, Zafer(2)
- Gücer, Mehmet Ali(2)
- Güloğlu, Zikrullah Samet(2)
- Temizel, Irfan(2)
- Abdioǧlu Yazar, Emel(1)
- Akpınar, İbrahim(1)
- Aktağ, Alican(1)
- Aydurmuş, Tanju(1)
- Bilici, Ozgur(1)
- Chen, Bin(1)
- Cicerali, Derya(1)
- Demir, Yilmaz(1)
- Güloglu, Z. Samet(1)
- Gündüz, Ramazan(1)
- Keskin, Serdar(1)
- Ruffet, Gilles(1)
- Sadiklar, M. Burhan(1)
- Saydam Eker, Çiğdem(1)
- Sefa Güzeldal(1)
- Siebel, Wolfgang(1)
- Uysal, Ibrahim(1)
- Vural, Alaaddin(1)
- Yilmazer, Sinan(1)
- YÜCELc, Cem(1)
- Çakmak, Gökhan(1)
- Çimen, Okay(1)
- Şen, Cüneyt(1)
Yayınlar
- Yüksek Lisans TeziAçık Erişim2026Gölönü plütonu’nun (Kürtün-Gümüşhane) petrografisi ve mineral kimyası
Sefa Güzeldal
Doğu Pontidler, farklı yaş ve bileşime sahip çok sayıda plütonik kayaç topluluğunu barındırmaktadır. Gümüşhane’nin Kürtün ilçesinde yer alan Orta Eosen yaşlı Gölönü Plütonu, kendine özgü petrografik ve jeokimyasal özellikleriyle dikkat çekmektedir. Bu çalışmada, plütona ait kayaçların petrografik özellikleri ve mineral kimyası verileri birlikte değerlendirilerek magmanın kristalleşme ve yerleşim süreçlerine ait fizikokimyasal parametrelerin (sıcaklık, basınç ve oksijen fugasitesi) belirlenmesi amaçlanmıştır. Ayrıca, mineral kimyası temelli yaklaşımlarla kristalleşme koşulları nicel olarak değerlendirilmiştir. Plüton yaklaşık 14 km2’lik bir alan kaplamakta olup KD-GB doğrultulu bir uzanım sergilemektedir. Modal mineralojik veriler, kayaçların granodiyorit ve granit bileşiminde olduğunu göstermektedir. Dokusal özellikler ince ve orta taneli yapılarla birlikte yer yer porfirik, poikilitik ve grafik dokuların geliştiğini ortaya koymaktadır. Kayaçların başlıca mineral bileşenleri plajiyoklaz, K-feldispat, kuvars, amfibol, biyotit ve Fe-Ti oksitlerinden oluşurken, zirkon, apatit, sfen ve allanit aksesuar mineraller olarak bulunmaktadır. Plajiyoklazlar oligoklas-labradorit aralığında (An0.1–56), K-feldispatlar ise ortoklaz bileşimindedir. Amfiboller kalsik amfibol grubuna ait olup magnezyoamfibol (Mg# = 0,78–0,85) bileşimi sunmaktadır. Amfibol ve plajiyoklaz mineral kimyasına dayalı hesaplamalar kristalleşme sıcaklıklarının 751–904 °C arasında değiştiğini göstermektedir. Jeobarometrik hesaplamalar 0,67–2,23 kbar basınç değerleri ve yaklaşık 3–7 km yerleşim derinliğine işaret etmektedir. Oksijen fugasitesi değerleri yaklaşık −13,0 ile −10,6 log birimi arasında değişirken, magma su içeriği %3,3–5,0 olarak hesaplanmıştır. Elde edilen veriler, Gölönü Plütonu’nun sığ kabuksal seviyelerde yerleşmiş, suca zengin ve çok evreli magmatik evrim süreçlerinden geçmiş bir magmatik sistemin ürünü olduğunu göstermektedir.
- MakaleAçık Erişim2026Scopus SJRQ4GEOLOGY 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.
- MakaleYalnız künye2026Scopus SJRQ1Mineralogical and geochemical controls on Co-V-Pt-Ni enrichment in manganese mineralization: evidence from the Dilli deposit, Eastern Türkiye
Gücer, Mehmet Ali; Çimen, Okay; Aktağ, Alican; Keskin, Serdar
The growing demand for critical minerals driven by the global energy transition and advanced technologies highlights the importance of unconventional metal reservoirs. This study investigates the Ni-, Co-, V-, and Pt-enriched Dilli manganese deposit (Kemaliye-Erzincan, Eastern Türkiye) to constrain the mineralogical, geochemical, and genetic controls on critical metal enrichment in Mn oxide mineralization. An integrated approach combining field observations, petrography, X-ray diffraction (XRD), whole-rock geochemistry, mineral chemistry, and stable C-O isotope analysis was applied to better understand the potential origin of critical mineral enrichments. The mineralization is dominated by Mn4+-bearing oxides, principally pyrolusite and hollandite, accompanied by minor rhodochrosite. High MnO (39-64 wt%) and very low Al2O3 and Fe2O3 contents indicate chemical precipitation with negligible detrital input. Discrimination diagrams and trace-element systematics consistently support a structurally controlled hydrothermal origin. Chondrite-normalized REE patterns display low total REE and very low Nd contents comparable to typical hydrothermal deposits, whereas neutral to slightly positive Ce anomalies and non-chondritic Y/Ho ratios suggest limited oxidative interaction with surface-derived fluids rather than primary marine hydrogenetic growth. Stable C–O isotope compositions of co-genetic calcite are inconsistent with a purely marine depositional environment and indicate precipitation from low-to moderate-temperature hydrothermal fluids. Mineral chemistry reveals strong phase-specific partitioning: hollandite preferentially incorporates V and Ba, whereas pyrolusite is enriched in Ni. Cobalt occurs in both phases, whereas Pt may also be present in both Mn oxide phases, suggesting that trace-element distribution is influenced by both crystallochemical and physicochemical controls. The enrichment of Ni, Co, and Pt is most plausibly linked to hydrothermal fluid circulation through ultramafic units, which likely acted as the primary metal source prior to precipitation. The Dilli deposit thus represents a structurally controlled hydrothermal Mn system enriched in critical metals, emphasizing the exploration relevance of Mn oxide mineral chemistry in identifying alternative sources of critical metals in Türkiye.
- MakaleAçık Erişim2025Mineral 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.
- MakaleAçık Erişim2024Scopus SJRQ4Mineral chemistry, petrography and crystallization conditions of the Middle Eocene Kazıkbeli Pluton (Eastern Pontides, NE Türkiye)
Güloğlu, Zikrullah Samet; Kaygusuz, Abdullah; Aydinçakir, Emre; YÜCELc, Cem
The Eastern Pontides host a diverse suite of plutonic rocks spanning a wide range of ages and compositions. Among these, the Middle Eocene Kazıkbeli pluton, located in the Kürtün district of Gümüşhane, stands out due to its distinctive petrological characteristics. This study aims to unravel the petrological implications of petrographic and mineral chemical data to determine the physicochemical conditions (temperature, pressure, oxygen fugacity) under which the Kazıkbeli magma crystallized and was emplaced. By integrating mineral chemical data, we seek to quantify emplacement pressure, crystallization temperature, and oxygen fugacity. A comprehensive understanding of the genetic relationships and physicochemical properties of the Kazıkbeli pluton rocks, as determined through geological, petrographic and mineral chemistry, is crucial for elucidating the geological evolution of the Eastern Pontides. The Kazıkbeli Pluton exhibits a predominant NE-SW orientation and encompasses an area of roughly 46 km2. Modal mineralogical analysis reveals a compositional spectrum ranging from gabbroic diorite to monzogranite, with granodiorite and tonalite being the most prominent rock types. Textural variations encompass fine-to medium-grained, porphyritic, poikilitic, and occasionally graphic textures. The primary mineral assemblage of the pluton comprises plagioclase, orthoclase, quartz, amphibole, biotite, and Fe-Ti oxides. Accessory minerals include zircon, apatite, sphene, and allanite. Plagioclases are labradorite to oligoclase (An26 to An66) in composition. K-feldspar minerals exhibited an orthoclase composition (Or80 to Or97). All amphiboles belong to the calcic amphibole field and exhibit a magnesio-hornblende (Mg#=0.63-0.73) composition. Biotites crystallized as solidified melt products with compositions between annite and phlogopite endmembers, plotting close to the magnesium-rich (Mg#=0.52-0.58) end of the phlogopite solid solution series. Calculated crystallization temperatures derived from amphibole and biotite data range from 712°C to 824°C. Pressure estimations calculated using amphibole-plagioclase, amphibole and biotite suggest a range of 0.04 to 2.06 kbar. Oxygen fugacity (ƒO2) values calculated using amphibole and biotite fall between -12.5 and -16.1. Amphibole-based water content estimations indicate a range of 3.7% to 5.7% for the pluton. Biotite compositions within the studied Kazıkbeli pluton rocks exhibit characteristics suggestive of a potential mantle origin. Geobarometric calculations based on mineral chemistry data with geological and petrographic features indicate the emplacement of the Kazıkbeli Pluton at relatively shallow depths within the crust (~1 to 8 km).
AtıfScopus1WoS1OpenAlex1
İncele - MakaleAçık Erişim2024Scopus SJRQ3Eocene magmatism related to postcollisional extension in the Eastern Pontides (NE Turkiye): 40Ar-39Ar geochronology, geochemistry, and whole-rock Sr-Nd-Pb-Hf isotopes
Aydinçakir, Emre; Yücel, Cem; Kaygusuz, Abdullah; Bilici, Ozgur; Yilmazer, Sinan; Ruffet, Gilles
The mineral chemistry, whole-rock geochemistry, 40 Ar / 39 Ar dating and Sr-Nd-Pb-Hf isotopes of the Eocene Narman (Erzurum) Volcanic rocks in the southeast of the Eastern Pontides Orogenic Belt (EPOB, NE Turkiye) were investigated. The Narman Volcanites consist of basaltic dyke, basaltic lava, and basaltic volcanic breccia facies. Volcanites contain plagioclase (An34-80), 34-80 ), clinopyroxene (Wo38- 38- 47En41-50Fs5-18), En 41-50 Fs 5-18 ), and olivine (Fo 68-90 ) as phenocrystals with magnetite/titanomagnetite microphenocrysts. New 40 Ar- 39 Ar ages suggest that these volcanic rocks erupted between 44.5 +/- 0.1 and 43.4 +/- 0.1 Ma, within the Middle Eocene (Lutetian). Narman Volcanites have calcalkaline character, with medium-high K content. Volcanites are enriched in large ion lithophile elements (LILE) and light rare earth elements (LREE), while they are depleted in terms of high field strength elements (HFSE). Chondrite-normalized rare earth element distributions have concave shape with moderate enrichment (LaN/LuN= N /Lu N = 2.78-7.99), leading to consideration that the magmas forming the volcanics derived from similar sources. Isotopically, the rocks in the Narman Volcanites have low-medium initial 87 Sr/ 86 Sr values (0.70405-0.70485), initial 143 Nd/ 144 Nd values (0.512606-0.512848) and positive Nd i (+0.5 - +5.2). Depleted mantle Nd model ages were T DM1 = 0.29-0.62 Ga and T DM2 =0.43-0.83 Ga. (206Pb/204Pb)i, 206 Pb/ 204 Pb) i , (207Pb/204Pb)i, 207 Pb/ 204 Pb) i , and (208Pb/204Pb)i 208 Pb/ 204 Pb) i values vary in the ranges of 18.246-18.709, 15.578-15.616, and 38.225-38.791, respectively. The initial (176Hf/177Hf)i 176 Hf/ 177 Hf) i ratios for the volcanites are between 0.282770 and 0.283013, while the epsilon Hf values range from +7.6 to +9. All the evidence supports the conclusion that the parental magma for the rocks probably derived from an enriched lithospheric mantle, previously metasomatized by fluids derived from subducted slab during asthenospheric upwelling, due to fragmented asymmetric delamination in a postcollisional extensional tectonic environment.
AtıfScopus4WoS3OpenAlex5TR Dizin2İncele - MakaleYalnız künye2022Scopus SJRQ1Eocene magmatism and associated Fe-Cu mineralization in northeastern Turkey: a case study of the Karadağ skarn
Sipahi, Ferkan; Saydam Eker, Çiğdem; Akpınar, İbrahim; Gücer, Mehmet Ali; Vural, Alaaddin; Kaygusuz, Abdullah; Aydurmuş, Tanju
The metallogenic belt containing numerous skarn mineralized systems starting from Eastern Europe continues through Turkey and Iran. The study area in the Eastern Pontides is within this metallogenic belt. The 44.39 ± 0.53 Ma Karadağ Intrusion sourced skarn mineralization is located along the granitoid-to-limestone contact. The Karadağ Intrusion is an arc-like pluton with medium–high K calc-alkaline and peraluminous–metaluminous affinity. The Karadağ Fe–Cu skarn mineralization (Gümüşhane, Turkey), an exoskarn, is hosted by Late Cretaceous limestone and consists of early garnet, clinopyroxene, and orthoclase with late epidote and chlorite. Primary ore minerals are magnetite and haematite, accompanied by minor amounts of chalcopyrite and pyrite. Pyroxene comprises mostly diopside and less hedenbergitic diopside and johannsenite. Wollastonite is very rare. Garnet is andradite and grossular–andradite. Thus, all these results imply that the Karadağ Fe–Cu skarn mineralization formed under relatively oxidized and Fe-rich conditions. The homogenization temperatures of the fluid inclusions vary from 189°C to 405°C for quartz and 186°C to 430°C for calcite. The salinity contents in the fluid inclusions are within 0.2–9 wt% NaCl equivalent for quartz and 0.4–14.8 wt% NaCl equivalent for calcite. First melting temperatures between −36.5 and −47.4°C were attained with the presence of NaCl–FeCl2± CaCl2 in the initial phase of fluid inclusions. The first melting in the later stage of fluid inclusions is between −3.8 and −17.2°C, thereby, supporting the existence of NaHCO3-Na2CO3-KCl-type salt composition. The δ18O values of minerals are 1.7–10.3‰ for garnet, 11.1–14.6‰ for quartz, 6.4 to 6.8‰ for epidote, and 2.8–3.8‰ for magnetite in the Karadağ skarn mineralization. The δ18O value of epidote indicates magmatic fluid, whereas those of garnet, magnetite, and quartz suggest magmatic fluids together with less meteoric effect. The δ18O values in limestone (18.7 to 22.3‰), marble (8.7‰), and calcite (10.5 to 12.2‰) were depleted relative to typical δ18O contents of marine carbonates (20 to 30‰). Moreover, the C isotope values of calcite (−5.4 to −1.4‰), marble (−2.1‰), and limestone (1.0 to 1.2‰) reflect those of metamorphic rocks and skarns (−4.0 to 3‰ and −18 to 2‰). Mineral paragenesis, fluid inclusion, and stable isotopic signatures are consistent with ore mineralization caused by the interaction of magmatic fluids with carbonate host rocks. Karadağ Fe-Cu skarn mineralization, associated with Karadağ postcollisional magmatism, is an example of skarn mineralized system in the Eastern Pontides.
AtıfScopus16WoS14OpenAlex17İncele - MakaleAçık Erişim2020Scopus SJRQ3Emplacement conditions of magma(s) forming Jurassic plutonic rocks in Gümüşhane (Eastern Pontides, Turkey)
Aydinçakir, Emre; Gündüz, Ramazan; Yücel, Cem
In this study, the petrography, mineral chemistry and crystallization conditions were reported for the Alemdar and Işıkdere plutons located in limited areas in the south of the Eastern Pontides. These plutons, which trend mostly in NE-SW directions, were emplaced by cutting the Early-Middle Carboniferous-aged Gümüşhane Granitoid and Early-Middle Jurassic Şenköy formation. Petrographically, the studied plutons are compositionally fine to medium grained quartz-diorite, quartz monzodiorite and tonalite. The rocks in the plutons have granular, poikilitic, monzonitic, graphic and rare porphyritic textures with consist of plagioclase, (An05-92), hornblende (Mg# = 0.52-0.81), biotite (Mg# = 0.32-0.67), orthoclase, quartz and Fe-Ti oxide. According to thermobarometric calculations, plutons have crystallization temperatures, pressures and oxygen fugacity values ranging from 541°C to 938°C, 0.1 to 4.4 kbar, and -23 to-12, respectively. The estimated water content calculated from amphibole is between 4.4 to 7.8%. It can be concluded that the studied plutons were emplaced at mid to shallow crustal depths (~4-15 km).
AtıfScopus12WoS11OpenAlex4TR Dizin7İncele - MakaleYalnız künye2019Scopus SJRQ1Geochronology, geochemistry, and petrology of adakitic Pliocene–Quaternary volcanism in the Şebinkarahisar (Giresun) area, NE Turkey
Yücel, Cem
The Pliocene–Quaternary volcanics in NE Turkey are mainly hornblende–phyric trachyandesites having a narrow range of SiO 2 from 61.88 to 63.00 wt.% and exhibiting adakitic signatures with their Na 2 O (3.67–4.27 wt.%), Al 2 O 3 (16.19–16.80 wt.%), Y (14.1–16.5 ppm) contents and K 2 O/Na 2 O (0.87–1.12), Sr/Y (44.24–54.90), and La/Yb (36.80–43.88) ratios. Plagioclases as the main mineral phases show a wide range of compositions, and weak normal and reverse zoning. Hornblendes are generally edenite and pargasite (Mg#: 0.39–0.74). Clinopyroxenes are augite (Mg#: 0.58–0.76). Biotites have Mg# ranging from 0.45 to 0.66. The textural and compositional variations indicate disequilibrium crystallization possibly arising from magma mixing. The U–Pb zircon dating of the adakitic volcanics yielded 3.4–1.9 Ma. The studied rocks display moderate light rare earth element /heavy rare earth element ratios and enrichment in the lithophile element and depletion in high field strength element, implying that the parental magmas were derived from mantle sources previously enriched by slab-derived fluids and/or subducted sediments. The crystallization temperature and pressure estimations based on the clinopyroxene thermobarometry range from 1144 to 1186°C and from 3.92 to 7.97 kbar, respectively. Hornblende thermobarometry, oxygen fugacity, and hygrometer calculations yielded results as 908–993°C at a pressure of 2.87–5.22 kbar, water content of 4.4–8.4 wt.%, and relative oxygen fugacity (ΔNNO log units) of −0.6 to 0.9, respectively. Biotite thermobarometry suggests relatively higher oxygen fugacity conditions (10 –13.33 to 10 –17.60 ) at temperatures of 676–819°C and at pressures from 1.15 to 1.76 kbar. In the light of the obtained data and modelling, it can be concluded that the magmas of the adakitic volcanics were derived from enriched mantle source through relatively higher partial melting and experienced magma mixing with melts at the crustal level. Additionally, the fractional crystallization and assimilation-fractional crystallization processes may have played an important role during the evolution of the studied volcanics.
AtıfScopus28WoS27OpenAlex27İncele - MakaleAçık Erişim2018Scopus SJRQ4Petrography, mineral chemistry and crystallization conditions of cenozoic plutonic rocks located to the north of Bayburt (Eastern Pontides, Turkey)
Kaygusuz, Abdullah; Yücel, Cem; Arslan, Mehmet; Sipahi, Ferkan; Temizel, Irfan; Çakmak, Gökhan; Güloglu, Z. Samet
The Eastern Pontides comprise many intrusive bodies varying in composition, size and age from Palaeozoic to Cenozoic. Especially Cenozoic aged bodies are commonly observed in the southern part, while they are rarely exposed in the northern part of the Eastern Pontides. In this study, the petrography and mineral chemistry of the Cenozoic aged Çiçekli, Somarova, Sorkunlu, Şaşurluk, Aydintepe, Kemerlikdagi and Pelitli plutons located to the north of Bayburt are determined, and the crystallisation conditions of the studied bodies were estimated by means of thermobarometer calculations. The studied plutons extend mostly in NE-SW directions and are approximately ellipsoid in shape. The contacts between the plutons and surrounding rocks are sharp, and plutons commonly contain mafic microgranular enclaves (MMEs) of different sizes. Petrographic and mineral chemistry studies reveal some disequilibrium textures reflecting the magma mixing process. Based on modal mineralogy, the plutonic rocks are gabbroic diorite, diorite, tonalite, granodiorite and monzogranite in composition. The rocks have fine to medium granular, porphyric, monzonitic, poikilitic, occasionally myrmekitic and micrographic textures. The main minerals are labradorite and albite (An68-02), magnesiohornblende and actinolite (Mg# = 0.6-0.9), diopside and augite (Wo44-46), clinoenstatite (En53-57) and Fe-Ti oxide minerals. Crystallization temperatures calculated from amphibole, biotite, clinopyroxene, magnetite and ilmenite minerals are 405°C to 1161°C, pressure values are 0.1 to 2.7 kbar, and oxygen fugacity (log10 fO2) is -20 to -12. Estimation of water content calculated by using amphiboles is between 2.9 and 6.8%. Based on obtained data, it is suggested that the studied plutons were emplaced at shallow depths (∼ 1-8 km).
AtıfScopus16WoS12OpenAlex9TR Dizin5İncele - MakaleAçık Erişim2018Scopus SJRQ4Mineral chemistry, whole-rock geochemistry and petrology of Eocene I-type shoshonitic plutons in the Gölköy area (Ordu, NE Turkey)
Temizel, Irfan; Abdioǧlu Yazar, Emel; Arslan, Mehmet; Kaygusuz, Abdullah; Aslan, Zafer
The Eocene intermediate to felsic plutons are widespread in varying sizes and compositions throughout the Eastern Pontides Orogenic Belt in NE Turkey. Of these, two monzonitic bodies (namely the Eriko Tepe and Göl Tepe Plutons) in the Gölköy (Ordu) area, extend nearly in the orientation of NWSE and E-W and were emplaced into the Upper Cretaceous and/or Eocene volcanic and sedimentary rocks. Petrographically, the studied monzonitic plutons are compositionally fine to medium grained monzonite, monzodiorite and subordinate quartz-monzonite. They consist of plagioclase (An35-67), K-feldspar (Or61-96), quartz, clinopyroxene (Wo28-49En35-51Fs10-25), biotite (Mg#: 0.53-0.73) ± hornblende (Mg#: 0.65-0.82), Fe-Ti oxide with monzonitic, poikilitic, perthitic, rare antirapakivi and graphic textures. Mineral thermobarometer estimations imply that the plutons were crystallized in P-T conditions of mid to shallow crustal levels. Petrochemically, these monzonitic plutons show post-collisional, I-type, metaluminous (A/CNK=0.76-0.93) and shoshonitic features. The wholerock major oxide and trace element variations suggest that fractionational crystallization played a significant role in the evolution of these monzonitic plutons. The primitive mantle-normalized trace element patterns of the studied plutons are similar to each other with enrichment in large ion lithophile elements, Th, Ce and negative Nb and Ti anomalies. Moreover, the chondrite-normalized rare earth element plots of the plutons show moderately enriched concave-shaped patterns (LaN/LuN=9.3-12.6) with negative Eu anomalies (EuN/Eu∗=0.69-0.84), all of which imply plagioclase and clinopyroxene ± hornblende fractionations during their evolution. The geochemical data suggest that the monzonitic plutons have evolved from parental magmas derived from the melts of enriched lithospheric mantle, in a post-collisional setting.
AtıfScopus15WoS14OpenAlex14TR Dizin5İncele - MakaleYalnız künye2011Scopus SJRQ3Formation of skarns at Gumushane (Northeastern Turkey)
Sipahi, Ferkan
Skarn deposits are located in the NE Black Sea region of Turkey belonging to the Alpin metallogenic province. The Fe skarn deposit at Arnastal is hosted by Late Cretaceous carbonate rocks comprised of limestone and the skarn occurrence at Camibogazi dolomitic limestone, adjacent to the Eocene Zigana Granitoid. The prograde textures include rhythmic banding, spots, and mossiness, and the retrograde textures are shock-induced and brecciated. These are identified in the Fe skarn deposit at Arnastal, where there are mineral parageneses of andradite, actinolite, tremolite, epidote, quartz, magnetite, and hematite, and less pyrrboune and pyrite. Additionally, well-crystallized vesuvianite, well-crystallized phlogopite, and diopside in the skarn occurrence. at Camibogazi are identified. Some of the skarn minerals are calcic and have high Mg/(Mg + Fe) ratios. Clinopyroxene consists of diopside (Di(96.66-99.04)Hd(0.67-2.80)Jo(0.29-0.55)). Vesuvianite is mostly Mg-rich, and has a very low MnO content (<0.1 %). Other skarn minerals are Fe-rich. Garnet is characterized by oscillatory zoning and has an andradite composition (Ad(72)Gr(28) to Ad(98)Gr(2)). Epidote has an Fe content of 8.96 to 12.42 wt%. Magnetite is generally massive and sporadically banded with some martitization. The formation temperatures of skarn minerals range from 330 to 600 degrees C. In addition, mass change calculations from the granitoid and andesite toward the skarn zone indicate that there is considerable mass transfer of Si, Al, Fe, and Mg to the carbonate rocks during skarn formation. The average mass changes are estimated at a depletion of 41 g/100 g in granitoid and a gain of 8 g/100 g in andesite. Fe skarn deposit and skarn occurrence are characterized by early, high-temperature mineral assemblages dominated by the anhydrous minerals garnet and diopside and late low-temperature assemblages with hydrous minerals, such as vesuvianite, phlogopite, and epidote. The type of garnet and the abundance of magnetite with minor pyrite suggest that the Fe skarn deposit at Arnastal forms under relatively oxidized conditions. The type of clinopyroxene in the skarn occurrence at the Camibogazi shows oxidized skarns.
AtıfWoS26OpenAlex37İncele - MakaleAçık Erişim2009Scopus SJRQ1U-Pb SHRIMP zircon ages, geochemical and Sr-Nd isotopic compositions of the late cretaceous I-type Sariosman pluton, Eastern Pontides, NE Turkey
Kaygusuz, Abdullah; Chen, Bin; Aslan, Zafer; Siebel, Wolfgang; Şen, Cüneyt
The petrogenesis and U-Pb SHRIMP zircon ages of the Late Cretaceous Sariosman pluton in the Eastern Pontides is investigated by means of whole-rock Sr-Nd isotope data with field, petrographic and whole-rock geochemical studies. The bulk of the I-type Sariosman pluton consists of biotite-hornblende monzogranite, with minor quantities of porphyritic hornblende-biotite monzogranite. The biotite-hornblende monzogranite contains a number of mafic microgranular enclaves (MMEs) of quartz monzodiorite composition. U-Pb zircon sensitive high-resolution ion microprobe dating (SHRIMP) dates the magma emplacement age of the biotite-hornblende monzogranite at 82.7±1.5 Ma. The rocks of the pluton show high-K calc-alkaline, metaluminous to slightly peraluminous characteristics, and are enriched in large ion lithophile elements (LILE) and light rare earth elements (LREE) relative to high field strength elements (HFSE), thus displaying features of arc-related granitoids. Chondrite-normalised rare earth-element (REE) patterns have concave upward shapes (Lacn/Lucn= 10.1-17.4) with pronounced negative Eu anomalies (Eu/Eu*= 0.61-0.80). Initial εNd values vary between -3.0 and -4.1 and initial 87Sr/86Sr values between 0.7062 and 0.707. The MMEs are characterised by higher Mg-numbers (27-29) and lower values of both SiO2 (56-58 wt%) and aluminium saturation index (0.9-1.0), compared to the monzogranites. Fractionation of plagioclase, hornblende and Fe-Ti oxides played an important role in the evolution of the Sariosman pluton. The crystallisation temperatures of the melts ranged from 700 to 800 °C and a relatively shallow intrusion depth (~2 to 7 km) is estimated from the Al-in-hornblende geobarometry. The geochemical and isotopic compositions of the Sariosman pluton suggest an origin through dehydration melting of mafic lower crustal source rocks.
AtıfScopus50WoS48OpenAlex22TR Dizin12İncele - MakaleYalnız künye2008Scopus SJRQ4Mineralogy, mineral chemistry, and fluid inclusion investigation of Köstere hydrothermal vein-type deposit (Gümüşhane, NE-Turkey)
Demir, Yilmaz; Uysal, Ibrahim; Sadiklar, M. Burhan; Sipahi, Ferkan
Vein type Köstere ores were deposited along cracks formed as a result of NE-SW fault system in the late Cretaceous felsic volcanic rocks in the northeastern Black Sea Region of Turkey. Total silver content of the Köstere ore is controlled by total silver content of the hydrothermal solution, homogenization temperature of the ore minerals and modal abundances of the tetrahedrite-tennantite serie minerals. The Zn/Cd ratios of sphalerites from the Köstere deposit are close to those of granite-related classical vein-type hydrothermal deposits. Furthermore Co/Ni ratio in pyrite separates, higher than unit, suggests an acidic source for the ore forming fluids. Homogenization temperatures of 200-370 °C and salinity of 0-9.85 eq. wt% NaCl were obtained on the basis of fluid inclusions studies measured in quartz minerals. These data indicate that ore formation conditions for the Köstere ore are similar with the vein-type epithermal-mesothermal deposits, related to the magmatic fluids. The overall low salinities of fluids (on average: 5.4 eq. wt% NaCl) suggest that meteoric waters were involved in mineralization. The possibility of interactions between ascending hydrothermal fluids and dilute meteoric waters is supported by geological features and mineralogical data which indicate a shallow depth of mineralization. Torul Pluton, which is the younger acidic unit (72 my) in the area, is suggested to be related to the formation of Köstere deposit.
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