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- 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 SJRQ3Mineral 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).
AtıfScopus1WoS1OpenAlex1İncele - 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 - MakaleAçık Erişim2018Scopus SJRQ3Petrography, 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