Trace element geochemistry of Bitlis ignimbrites sourced by Quaternary Nemrut Volcano: inferences for A2-type magma generation in Eastern Anatolia post-collisional extensional setting

Authors : Hakan ÇOBAN, Özcan Ali KALKAN

Pages : 91-96

Doi:10.17678/beuscitech.1021499

View : 16 | Download : 12

Publication Date : 2021-12-20

Article Type : Research Paper

Abstract :In the study presented here, we investigated the K-Ar age determination and petrological significance of trace element compositions of Bitlis insert ignore into journalissuearticles values(Eastern Anatolia); ignimbrites associated with explosive activities of the well-known Nemrut volcano. K-Ar geochronological dating of Bitlis ignimbrite flow deposits gave the age of 790 ka which corresponds to the first products of pre-caldera stages of Nemrut stratovolcano. Bitlis trachydacitic ignimbrites with shoshonitic affinity are characterized by the typical negative anomalies of Eu, Nb-Ta, and Ti in chondrite-normalized spider and multi-element variation diagrams, and plot in the fields of within-plate and post-collisional tectonic setting in Rb vs Y+Nb discrimination diagram. Accordingly, similar to that of Nemrut volcanic products, trace element signatures insert ignore into journalissuearticles values(e.g., high Nb, Ce, Y, and Zr contents); of Bitlis ignimbrites show coincidence with geochemical characteristics of A2-type silicic magmas. Relative to the upper crust, higher La/Ba and Nb/La, and lower Ba/Ta and La/Ta ratios of Bitlis ignimbrites, which are close to that of Nemrut basalts, suggest an interaction between OIB-like basaltic magma and upper crust. Our results point to A2-type silicic magma generation in Eastern Anatolia post-collisional extensional setting, and Nemrut volcanic and pyroclastic rocks insert ignore into journalissuearticles values(e.g., Bitlis ignimbrites); formed by partial melting of upper crustal rocks at shallow level via interaction with OIB-like basaltic magma derived from a common mantle source.
Keywords : Bitlis ignimbrite, A2 type magma, K Ar dating, Eastern Anatolia