Petrological Properties of Ultramafic Rocks and Related Mafic Dykes in Savatlı-Özalp Ophiolite (Van-Eastern Anatolia)

Öz

Ophiolitic rocks located on the north of the Bitlis Zagros Suture Zone provide some regional information about the closure period of the Neotethys and subsequent processes. This study introduces petrographic and geochemical features of ultramafic and mafic rocks, including the Savatlı-Özalp ophiolite in the eastern  part of Lake Van. These ultramafic and mafic rocks, which are the part of an incomplete ophiolitic sequence, are tectonically transported to the region. Hydrothermal alteration and low-grade metamorphic effects are intensively observed in these ophiolitic rocks. Petrographically determined serpentine minerals in ultramafic rocks and prehnit and clorite minerals in mafic rocks are the most clear evidence for these alteration and metamorphic effect. Geochemical features of diabase dykes observed in Savatlı-Özalp Ophiolite tectonically indicate a generation from transition zone. Chondrite-normalized REE typically refer to island-arc tholeiite occurred on oceanic subduction zone. 

Anahtar Kelimeler

• Ophiolite,Ultramafic rocks,Diabase dyke,Pertology,Geochemistry

Savatlı-Özalp Ofiyolitinde (Van-Doğu Anadolu) Gözlenen Ultramafik Kayaçlar ve İlişkili Mafik Daykların Petrolojik Özellikleri

Öz

Bitlis Zagros Kenet Kuşağı’nın kuzeyinde bulunan ofiyolitik kayaçlar, bölgesel olarak Neotetis’in kapanma süreci ve sonrası hakkında önemli bilgiler sunmaktadır. Bu çalışmada, Van Gölü doğusunda Savatlı-Özalp Ofiyolitinde yer alan ultramafik ve mafik kayaçların petrografik ve jeokimyasal özellikleri ortaya konulmaktadır. Eksikli bir dizilim sunan ofiyolitteki ultramafik ve mafik kayaçlar, çalışma alanında tektonik olarak yer almaktadır. Bu kayaçlar içerisinde, hidrotermal alterasyon ve düşük dereceli metamorfizma etkisi yoğun olarak gözlenmektedir. Özellikle ultramafik kayaçlarda pertografik incelemeler sonucu belirlenen serpantin grubu minerallerin varlığı ile mafik kayaçlardaki prehnit ve klorit mineralleri bu etkinin en güzel kanıtlarıdır. Savatlı-Özalp Ofiyolitinde gözlenen diyabaz dayklarının jeokimyasal özellikleri, tektonik ortam açısından geçiş zonunu işaret etmektedir. Kondrite göre normalize edilen dayklar, ofiyolitin tipik olarak okyanus içi dalma batma zonu üzerinde ve ada yayı toleyitlerinde oluştuğunu ortaya koymaktadır.

Anahtar Kelimeler

• Ofiyolit,Ultramafik-mafik kayaç,Diyabaz dayk,Petroloji,Jeokimya

Kaynakça

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