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Turkish Journal of Earth Sciences

DOI

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Abstract

In northwestern Turkey, the Denizgören ophiolite and its sedimentary substratum, the Ezine Group, are enigmatic geological objects whose evolution remains problematic. Based on long-term fieldwork, we here propose a solution for their genesis and correlation. The whole of the Ezine Group, more than three km thick, is characterised by the systematic occurrence of carbonate rocks in the greenschist facies. It has been subdivided into three conformable formations: the Geyikli Formation, with a slight terrigeneous detrital nature, (Middle)-Late Permian in age; the Karadağ Formation, with platform-type sedimentation with local detrital input, Late Permian (Djulfian) in age; the Çamköy Formation, with a pronounced carbonate detrital nature, of Spathian to Carnian age. Based on facies organisation and distribution, the Çamköy Formation is interpreted as a syn-rift sequence, following a strong transgressive subsidence phase represented by the Geyikli and Karadağ formations. The Denizgören ophiolite, comprising serpentinised peridotite, tectonically overlies the Ezine Group along a metabasite unit, interpreted as its metamorphic sole. The latter shows an inverted metamorphic gradient, and consists of mylonitised prasinites and amphibolites with oceanic geochemical signatures. The Ar/Ar age of the amphibolite facies indicates a Barremian age (125 Ma), quite different from that of the Ezine Group. A major problem is that the Ezine Group and the Denizgören ophiolite (plus its metamorphic sole) have no lateral equivalent in the whole Aegean domain. However, we suggest that the Ezine Group represents a fragment of the Rhodopian passive margin, consequence of the Permo-Triassic rifting of the future Maliac/Meliata Ocean, also observed in Greece. The emplacement of the Denizgören ophiolite over the Ezine Group occured within the framework of the Balkanic orogen, a major compressional event, which affected the whole Rhodope area, and was characterised by northward nappe emplacement during Jurassic-Early Cretaceous times.

First Page

145

Last Page

176

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