Petrographical and petrological investigation of Kömürhan Ophiolite unit

ABSTRACT (Ph. D. Thesis) PETROGRAPHICAL AND PETROLOGICAL INVESTIGATION OF KÖMÜRHAN OPfflOLITE UNIT Melahat BEYARSLAN Fırat University Graduate School of Natural and Applied Sciences Department of Geological Engineering 1996, Page: 103 In the investigated area which is situated in the Eastern Taurus Orogenic Belt in the Southeast part of Elazığ, the following six different units crop out. 1- Palaeozoik - Mesozoic Pütürge Metamorphices, 2- Cretaceous Kömürhan Ophiolites, 3- Upper Cretaceous Elazığ Magmatics, 4- Middle Eocene Maden Complex, 5- Middle Eocene - Oligocene Kırkgeçit Formation, 6- Quvaternary alluviums. Pütürge Metamorphics consist of various schists, kyanite quartzites and recrystalized limestones. The contact between these metamorphics and other units are tectonics. The Upper Cretaceous Elazığ Magmatics are composed of basaltic volcanics, in general basaltic pillow lavas and granitic plutonics. The granitic plutonics cut the Kömürhan Ophiolites and basaltic volcanics. The Eocene Kırkgeçit Formation which starts with conglomerates and sandstones and continues upward with limestones covers Elazığ Magmatics and Kömürhan Ophiolite with an angular unconformity. The Maden Complex consist ofVI basaltic lavas, tuffs, lapillistones, aglomerate and red mudstones and limestone blocks. Quvateraary alluviums are represented by gravels, sands and silts. Kömürhan Ophiolites of which petrographic - petrological and geochemical properties are subject of this study, cover large area and overthrusted on to the Middle Eocene Maden Complex in the southern part and in the northern part the Elazığ Magmatics overthrusted on to the Kömürhan Ophiolites. The Kömürhan Ophiolites are composed of wherlite - pyroxenite, gabbros, diabase dikes complex and dikes cutting the gabbros. The geochemical data indicate that the Kömürhan Ophiolites are derived from the tholeiitic magma, E type MORB. The lithological and geochemical features of Kömürhan Ophiolite unit compare to the features of supra - subduction zone ophiolites and differ from the typical oceanic ridge ophiolites. Therefore the Kömürhan Ophiolite accepted on a supra - subduction ophiolite. The Kömürhan Ophiolites were formed by spreading above a northward - dipping intra oceanic, subduction (supra - subduction) of Neothethyan Ocean during Upper Cretaceous and thrusted on the Maden Complex after Middle Eocene. KEY WORDS: Gabroic rocks, ophiolite, petrography, supra - subduction, Kömürhan, Eastern Taurus, Türkiye.