Comparison of the collision and extensional related mafic intrusive rocks within central anatolia, Turkey

Abstract

The closure of Neotethys induced collision and extension related basic magmatism within the Central Anatolia during the late Cretaceous and Early Paleogene. The products of the basic magmatism are alkaline and tholeiitic in character. The temporal and spatial evolution of the basic magma within the Central Anatolia has a great role in the interpretation of magmato–tectonic evolution of the region. The lack of radiometric age for the mafic magmatic rocks let to discussion in the explanation of the nature of these magmatism. The recent study deal with detail mineralogical and petrographic studies with spectroscopically methods. The evaluation of plagioclase, amphibole, pyroxene and biotite by using the Raman confocal spectroscopy and Electron microprobe methods. Mafic magmatic rocks have a wide exposure with different colour and textures in the Central Anatolia. In this study, Hacıibrahimuşağı, Gömük, Akçakent and Hamit gabbros are selected for the purpose of the investigation of this research. Hacıibrahimuşağı and Gömük gabbros are mainly composed of plagioclase, amphibole, pyroxene with lack amount of biotite. The plagioclase compositions range from oligoclase to bytownite. The amphiboles are mainly hornblende and the pyroxenes are diopside in compositions. Akçakent and Hamit gabbros are mainly composed of plagioclase, nepheline, and pyroxene with lack amount of amphibole and cancrinite. Thermobarometry calculations from amphiboles of Hacıibrahimuşağı gabbros are ranging from 798 up to 944°C and 4.2–1.1 kbar with 15.9–4.3 km emplacement depth. Furthermore, the formation of the pyroxene minerals of these rocks are 1388-1464°C and 19.9-25.6 kbar with 91-98 km emplacement depth. Thermobarometry calculations from pyroxene of Akçakent and Hamit gabbros are ranging from 1083 up to 1270°C and 1.8-20.7 kbar with 7-80 km emplacement depth of these pyroxenes. All the detail mineralogical, petrographical and thermobarometry studies reveal that the Hacıibrahimuşağı and Gömük gabbros are tholeiitic in nature and formed due to the Inner Tauride Ocean collision in the Central Anatolia. However, the Akçakent and Hamit gabbros are alkaline in nature and formed due to the extensional of the Anatolian Plate after the collision during Late Cretaceous and Early Paleogene in the region. © SGEM2019.