A Deformation Structure and Origin of Metamorphic Sole Rocks Beneath the Eldivan and Ahlat Ophiolites (Çankırı), Northern Anatolia

Abstract

Eldivan and Ahlat ophiolitic rocks are located in the central part of the İzmir-Ankara-Erzincan Suture Belt at the northwest of Çankırı (Türkiye). They occurred at the base of the Tethys Ocean in the Jurassic-Cretaceous period and moved on the continent during the closure period of the ocean in the Late Cretaceous. Metamorphic sole rocks in ophiolites are formed by mostly amphibolites and partially quartzite and schist. This study aims to determine the origin, temperature and pressure of metamorphic sole rocks in Eldivan and Ahlat ophiolites. According to energy-dispersive X-Ray spectroscopy (EDS) analysis of amphibolite samples from Eldivan and Ahlat ophiolites, amphibole minerals take place in edenite (Mg-hornblende)-pargasite range. In contrast, the plagioclase minerals have albite composition. EDS analysis and petrographical investigations show that all relict pyroxene minerals in rock are primary character. The formation temperature range of the rocks is calculated as 501 - 642 °C. As a result of geochemical analysis, the metamorphic sole rocks at Eldivan and Ahlat ophiolites derived from an OIB-like mantle.