The geochemistry and petrology of the ophiolitic rocks from the Kahramanmaraş region, southern Turkey

Authors : Utku BAĞCI

Pages : 536-562

Doi:10.3906/vet-1107-14

View : 21 | Download : 6

Publication Date : 0000-00-00

Article Type : Research Paper

Abstract :The regionally important dismembered ophiolitic sequence from the southern Kahramanmaraş region, located along the Arabian-Eurasian collision zone in southeastern Turkey, contains harzburgitic tectonites, ultramafic to mafic cumulates, isotropic gabbros and ophiolite-related metamorphic rocks. The ultramafic-mafic cumulate rocks are composed of wehrlite, lherzolite, olivine websterite, olivine gabbronorite, olivine gabbro and gabbro. The crystallization order of the cumulus phases, the presence of high Ca-plagioclase insert ignore into journalissuearticles values(An83-94);, highly magnesian clinopyroxene insert ignore into journalissuearticles values(Mg#78-93);, olivine insert ignore into journalissuearticles values(Mg#71-91); and their coexistence in the ultramafic-mafic cumulate rocks indicate a suprasubduction zone insert ignore into journalissuearticles values(SSZ); environment and suggest that the cumulates were derived from an island arc tholeiitic insert ignore into journalissuearticles values(IAT); magma. The isotropic gabbros are mainly represented by hornblende gabbro, gabbro and diorite rocks. The major and trace element geochemistry of the isotropic gabbros reveals two different magma types. The first group is characterized by low TiO2 insert ignore into journalissuearticles values(0.91-1.52 wt.%); and Zr insert ignore into journalissuearticles values(35-79 ppm);, and REEs exhibiting flat to slightly depleted LREE insert ignore into journalissuearticles values(LaN/YbN = 0.38 to 0.67); patterns, geochemically similar to island arc tholeiites. The second group is characterized by higher TiO2 insert ignore into journalissuearticles values(2.67-3.87); and Zr insert ignore into journalissuearticles values(176-351 ppm); and displays significant LREE enrichment insert ignore into journalissuearticles values(LaN/YbN = 10.9 to 14.5); patterns, which are geochemically similar to oceanic island basalt insert ignore into journalissuearticles values(OIB);. Metamorphic sole rocks are represented by alkali amphibolites and are similar to OIB. All the evidence suggests that the ophiolitic rocks of the southern Kahramanmaraş region are associated with different types of magma generation and were emplaced onto the Arabian passive margin along the southern branch of the Neotethys oceanic basin during the Late Cretaceous.
Keywords : Key words Suprasubduction, island arc tholeiite, alkaline, cumulate, ophiolite, Turkey