Nature and significance of Late Cretaceous ophiolitic rocks and their relation to the Baskil granitic intrusions of the Elaziğ region, SE Turkey
Published:January 01, 2006
Tamer Rizaoğlu, Osman Parlak, Volker Hoeck, Fіkret İşler, 2006. "Nature and significance of Late Cretaceous ophiolitic rocks and their relation to the Baskil granitic intrusions of the Elaziğ region, SE Turkey", Tectonic Development of the Eastern Mediterranean Region, A. H. F. Robertson, D. Mountrakis
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The Elaziğ region in SE Turkey comprises, in descending order, the Palaeozoic– Mesozoic Malatya–Keban platform, an ensimatic island arc unit (i.e. Elaziğ magmatic rocks–Yüksekova complex), and ophiolitic rocks (i.e. Kömürhan) of Late Cretaceous age. All of these were intruded by the Baskil granitic rocks. These tectonomagmatic-stratigraphic assemblages were emplaced over the Middle Eocene volcano-sedimentary Maden complex to the south during the evolution of the SE Anatolian orogen. The Kömürhan ophiolite exhibits an intact ophiolite pseudostratigraphy. The base of this has been metamorphosed to amphibolite facies during intraoceanic subduction–thrusting. The amphibolitic rocks were intruded by synkinematic granitic rocks (Baskil magmatic rocks). The ensimatic island arc volcanic rocks are widely distributed in the region. The contact of the volcano-sedimentary unit with the underlying Kömürhan ophiolite is a thrust dipping to the north. The rock assemblages of the volcano-sedimentary unit suggest formation of small volcanic edifices above a subduction zone, coupled with debris-flow deposits and volcaniclastic turbidites. The whole-rock and mineral chemistry of the Kömürhan ophiolite and the ensimatic island arc volcanic rocks suggests that they represent a comagmatic tholeiitic suite, formed in the Late Cretaceous in a suprasubduction zone (SSZ) setting. The amphibolites beneath the Kömürhan ophiolite indicate derivation from an island arc tholeiite (IAT) protolith. The geological and geochemical evidence from the Elaziğ region suggests the following evolutionary scenario. The Kömürhan ophiolite was formed above a north–dipping subduction zone between the Arabian platform to the south and the Tauride platform to the north in Late Cretaceous (c. 90 Ma). An ensimatic island arc assemblage was then built on the SSZ-type crust. The metamorphic sole was formed by metamorphism of IAT-type basalts that were detached from the front of the overriding Kömürhan ophiolite and then underplated. These units were then accreted to the base of the Tauride active margin to the north, where both units were cut by the Baskil granitic rocks around 85 Ma.
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Tectonic Development of the Eastern Mediterranean Region
The Eastern Mediterranean region is a classic area for the study of tectonic processes and settings related to the development of the Tethyan orogenic belt. The present set of research and synthesis papers by Earth scientist from countries in this region and others provides an up-to-date, interdisciplinary overview of the tectonic development of the Eastern Mediterrenean region from Precambrian to Recent. Key topics include continental rifting, ophiolite genesis and emplacement, continental collision, extensional tectonics, crustal exhumation and intraplate deformation (e.g. active faulting). Alternative tectonic reconstructions of the Tethyan orogen are presented and discussed, with important implications for other regions of the world. The book will be an essential source of information and interpretation for academic researchers (geologists and geophysicists), advanced undergraduates and also for industry professionals, including those concerned with hydrocarbons, minerals and geological hazards (e.g. earthquakes).