Nature of the gabbro in central anatolia: Geological observation and spectroscopic applications, Turkey

Abstract

Central Anatolia is bounded by the Izmir Ankara Erzincan (IAE) Suture Zone dipping northward beneath the Pontides at the north and the Inner Tauride (IT) Suture Zone with NE-dipping Central part of Turkey with triangular shaped structure. The Paleozoic metamorphic rocks are formed the basement of the Central Anatolia and obducted by the remnant of Inner Tauride ophiolitic products. Both of the units injected by Late Cretaceous age of the felsic and mafic intrusive unit. The mafic products mainly composed of gabbroic rocks and formed the less exposure crystalline magmatic rocks in comparison to the felsic crystalline magmatic rocks. The gabbroic rocks have a wide range in the exposure and mainly exposed at the eastern and far eastern part of Central Anatolia. They are ranging from a few meters up to kilometer square in dimension. The largest outcrops mostly accumulated with felsic intrusion in Central Anatolia. Different geographical distribution, colour, texture and mineral chemistry led to evaluate different source and nature in the region. MORB normalized elemental pattern of most of the gabbroic rocks of the Central Anatolian are enriched with the LIL elements with respect to HFS elements. Whole rock, trace and rare earth element results reveal that most of these mafic rocks are almost reveal almost similar geochemical behavior and patterns. The Raman spectra of the ophiolitic, intrusive and alkaline gabbroic rocks pyroxene mainly composed of augite, augite-diopside and augite- hedenbergite in composition respectively. The Electron Probe Micro Analysis (EPMA) results reveal that the pyroxene of the ophiolitic gabbro, intrusive gabbro and alkaline gabbro may crystalized at 178, 77 and 80 km depth with 46, 20 and 19 kilo bar pressure. Although the mineralogical, whole rock geochemical compositions are not able to differentiate between these gabbro the crystallization conditions of the pyroxene may be used in the classification of the gabbro types in Central Anatolia. © SGEM2019.