Tectonic Implications of Some Cretaceous Pillow Basalts from the North Anatolian Ophiolitic Mélange(Central Anatolia-Turkey) to the Evolution of Neotethys

Turkish Journal of Earth Sciences

BORA ROJAY¹ 

关键词: Seamount;    Geochemistry;    Callovian-Hauterivian Interval;    Tethys;    Ankara Mélange;   

学科分类：地球科学(综合)

来源: Scientific and Technical Research Council of Turkey - TUBITAK

【 摘 要 】

The most widespread blocks within the North Anatolian ophiolitic mélange of central Anatolia (Turkey) are ophiolitic fragments, Jurassic-Cretaceous carbonate blocks and pillow basalts. The blocks of pillow basalts have an immobile trace-element geochemistry that is characteristic of ocean-island alkali basalts. An N-MORB-normalized spider diagram shows a distinctive enrichment of most incompatible trace elements and exhibits a far greater range of absolute abundances than N-MORB. Selected incompatible-element contents and ratios of basalts show high Ba/Nb (~8),low Zr/Nb(~5)and low La/Nb(~0.5)relative to N-MORB. The presence of thin-shelled \"Protoglobigerina\" and Cadosina associated with miliolids and epistominid foraminifers indicates that the age of the pink biomicritic carbonates deposited between the pillow basalt lobes is within the Callovian-Hauterivian interval. Collectively, these results support the presence of a seamount on the Neotethyan oceanic crust and prove the presence of an older oceanic crust along the northern branch of Neotethys.

【 授权许可】

Unknown