A GEOLOGICAL AND PETROLOGICAL OVERVIEW OF THE HISTORY OF KIRA MOUNTAIN: AN APPROACH TO THE SIMILARITY AND DIFFERENCE OF KARACADAG

Abstract

The volcanism of Kıra Mountain, at south of the Bitlis Zagros suture zone(BZK), was erupted from different joint systems by young extensional tectonicregime. The main geological and petrographic features of the Late MioceneKıra Mountain volcanics were investigated as well as the major oxide, traceelement and rare earth element geochemical characteristics. The KıraMountain volcanic products are classified as basanite, tephrite and trachybasalt and show alkaline character above the alkaline-subalkaline separationline. Nonetheless, the peripherals associated with these volcanics starts withthe Miocene aged Şelmo Formation. This formation is accompanied byOligocene Germik Formation and Eocene Gercus Formations. TheKaracadag volcanics are adjacent to the Lower, Middle and Late-CambrianSadan, Koruk and Sosink Formations, respectively, predominantly thePrecambrian Derik Formation. In addition to these formations, LateCretaceous Karababa and Karbogaz Formations, Late Cretaceous-PaleoceneGermav Formation, Eocene Midyat Formation and Eocene Şelmo Formationsare also contiguous. The phenocrysts of the Karacadag volcanics includeolivine, clinopyroxene, plagioclase and opaque minerals. In the KıraMountain volcanics, olivine, plagioclase and opaque minerals areaccompanied by sanidine and pyroxene. As reported by the geochemical andpetrographical studies, The Karacadag volcanics are mainly classified asbasalt and trachy-basalt, tephrite, basanite and hawaiite. Moreover theselavas are mainly alkaline and present subalkaline transition. The Karacadagvolcanics erupted in three different stages with different phases, and the Kıramountain volcanics were found to be identical with the Siverek stage.