Neogene and Quaternary volcanism of southeastern Turkey
Published:January 01, 2000
Jan Arger, John Mitchell, Rob W. C. Westaway, 2000. "Neogene and Quaternary volcanism of southeastern Turkey", Tectonics and Magmatism in Turkey and the Surrounding Area, Erdin Bozkurt, John A. Winchester, John D. A. Piper
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Potassium-argon dating indicates two episodes of basaltic magmatism in south eastern Turkey at c. 19–15 and c. 2.3–0.6 Ma. Each produced olivine-titanaugite basalts, whose chemical compositions are difficult to classify using any conventional model in both the Anatolian continental fragment and the Arabian Platform. It is proposed here that both episodes of volcanism, and the associated crustal thickening and surface uplift, result from heating of the mantle lithosphere by crustal thickening caused by inflow of plastic lower crust from adjoining regions. Thus, although this study region has remained in a plate boundary zone for tens of millions of years, its volcanism has no direct relationship to local plate motions. It is suggested instead that both episodes of volcanism are the result of loading effects caused by glacial to interglacial sea-level variations, which will cause net flow of lower crust from beneath the offshore shelf to beneath the land: the moderate glaciations of Antarctica which began in the Early-Middle Miocene, and the more intense lowland glaciations of the northern hemisphere which began around c. 2.5 Ma.
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Tectonics and Magmatism in Turkey and the Surrounding Area
This volume contains 23 papers from a range of international contributors, describing recent research into the tectonics and magmatism of Turkey and its surroundings. This region is sited at the collision zone between Eurasia and Afro-Arabia and, as such, provides an extraordinarily complete and well-exposed record of the staged tectonic evolution of this sector of the Alpine-Himalayan orogen. The geological history of this area involves separation of continental fragments from the margin of Gondwana, their migration across the Tethyan oceans, the subsequent closure of these oceans and, finally, the development of the neotectonic regime, which continues to evolve to the present day. Such a comprehensive record is relevant to the understanding of collisional zones worldwide.
The volume is divided into five sections: Tethyan evolution, Neotethyan ophiolites, post-Tethyan basin evolution, neotectonics and igneous activity. The first two sections deal with Tethyan oceans, whose growth and subsequent closure dominated the geodynamic framework in the Mesozoic and Cenozoic. The subsequent sections deal with more recent geological developments from the Balkan Peninsula in the west to the Transcaucasus in the east that followed consumption of the Tethyan oceans. There is a broad mix of papers throughout the volume: wide-ranging review papers on ocean development and extensional tectonics are followed by detailed descriptions of petrology and geochemistry and geographically focused studies on basin evolution, specific aspects of extensional and strike-slip tectonics and discussions of the relationship of magmatic activity to the tectonic development of the area.
Tectonics and Magmatism in Turkey and the Surrounding Area presents up-to-date results and ideas from a large number of international contributors on a wide range of current research activity in this region. It is essential reading for all geoscientists with an interest in both academic and applied aspects of eastern Mediterranean geology.