Mineral chemistry of isotropic gabbro and plagiogranite from the Central Anatolian Ophiolites in the Derinkuyu (Nevşehir, Central Anatolia) region

Yıl 2025, Cilt: 31 Sayı: 8, 1505 - 1517, 17.12.2025

Ayşe Orhan , Musa Avni Akçe

https://doi.org/10.65206/pajes.63504

https://izlik.org/JA37UE57CH

Öz

The isotropic gabbro and plagiogranite belonging to the Central Anatolian Ophiolites, are exposed as stocks around Derinkuyu (Nevşehir). Plagiogranite, which cuts the isotropic gabbro, contains mafic microgranular enclaves (MME) belonging to these rocks. Gabbro and MME contain plagioclase, clinopyroxene and hornblende minerals. The isotropic gabbros are in hornblende-pyroxene and pyroxene-hornblende/hornblende gabbro compositions. Plagiogranite is composed of quartz, plagioclase and hornblende, and exhibits a tonalite composition. Mineral chemistry analysis results indicate that plagioclases in the gabbro, plagiogranite, and MME have compositions of andesine–bytownite (An47–85), andesine (An38–48), and labradorite–bytownite (An65–75), respectively. Clinopyroxenes (Mg#=0.73–0.84) and hornblendes (Mg#=0.57–0.79) are characterized by their high-Mg contents. Clinopyroxenes, diopside–augite (En37–43Fs12–15Wo42–47), and the hornblendes exhibit compositions of tschermakite–magnesio-hornblende. Clinopyroxene and hornblende data on the discrimination diagrams indicate the presence of an island arc for the source magma. Pyroxene and amphibole thermobarometry suggest that P–T crystallization conditions for clinopyroxene and hornblende 2.60–1.37 kbar 1199–1186°C and 1.95–1.09 kbar; 864–790°C, respectively. These data manifest that the magma of supra-subduction type ophiolite rise towards shallow lithospheric levels (9.2–3.9 km).

Anahtar Kelimeler

Isotropic gabbro , Plagiogranite , Mineral chemistry , Supra-subduction zone , Central Anatolia

Derinkuyu (Nevşehir, Orta Anadolu) yöresindeki Orta Anadolu Ofiyolitlerinden izotropik gabro ve plajiyogranitin mineral kimyası

https://izlik.org/JA37UE57CH

Öz

Orta Anadolu Ofiyolitlerine ait izotropik gabro ve plajiyogranitler, Derinkuyu (Nevşehir) çevresinde stoklar halinde yüzeylemektedir. İzotropik gabroyu kesen plajiyogranit, bu kayaçlara ait mafik mikrogranüler anklavları (MME) içerir. Gabro ve MME plajiyoklaz, klinopiroksen ve hornblend mineralleri içerir. İzotropik gabrolar, hornblend-piroksen ve piroksen-hornblend/hornblend gabro bileşimlerindedir. Plajiyogranit, kuvars, plajiyoklaz ve hornblendden oluşur ve tonalit bileşimi gösterir. Mineral kimyası analiz sonuçları, gabro, plajiyogranit ve MME’deki plajiyoklazların sırasıyla andezin–bitovnit (An47–85), andezin (An38–48) ve labradorit–bitovnit (An65–75) bileşimlerine sahip olduğunu göstermiştir. Klinopiroksen (Mg#=0.73–0.84) ve hornblendler (Mg#=0.57–0.79) yüksek-Mg içerikleriyle karakteristiktir. Klinopiroksenler, diyopsit–ojit (En37–43Fs12–15Wo42–47) ve hornblendler çermakit–magnezyum-hornblend bileşimleri sergiler. Sınıflama diyagramlarında klinopiroksen ve hornblend verileri, kaynak magma için bir ada yayının varlığını göstermektedir. Piroksen ve amfibol termobarometrisi, klinopiroksen ve hornblend için P-T kristalleşme koşullarının sırasıyla 2.60–1.37 kbar; 1199–1186°C ve 1.95–1.09 kbar; 864–790°C olduğunu göstermektedir. Bu veriler, dalma-batma zonu üstü tipi ofiyolit magmasının sığ litosferik seviyelere (9.2–3.9 km) doğru yükseldiğini ortaya koymaktadır.

Anahtar Kelimeler

İzotropik gabro , Plajiyogranit , Mineral kimyası , Dalma-batma zonu üstü , Orta Anadolu

Kaynakça

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