Jurassic Volcanism in the Eastern Pontides: Is it Rift Related or Subduction Related?

Authors : Cüneyt ŞEN

Pages : 523-539

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Publication Date : 0000-00-00

Article Type : Research Paper

Abstract :The Jurassic volcanic rocks in the centre of the northern zone insert ignore into journalissuearticles values(south of Trabzon City); provide important constraints on the evolution of Pontides. The investigated volcanic rocks form a transitional series between tholeiitic and calc-alkaline, and is dominated by basalt, basaltic andesite and andesite. Geochemically, they are enriched in LILE and LREE contents and depleted in HFSE [insert ignore into journalissuearticles values(La/Yb);N= 2.2 - 8.5; insert ignore into journalissuearticles values(Nb/La);N= 0.1 - 0.77);] compared to mid-ocean ridge basalts and have radiogenic Nd isotope ratios of eNdinsert ignore into journalissuearticles values(210 Ma);= -0.72 to 3.24. These trace element and isotope data suggest that these rocks were derived from low degrees of partial melting of spinel lherzolite that was metasomatized by subduction-related fluids and further underwent a degree of fractional crystallization in magma chambers before being extruded at the surface.
Keywords : Eastern Pontides, geochemistry, Sr Nd isotopes, Jurassic, basalt, Turkey