Whole rock trace elements and Sr-Nd isotope geochemistry of Kepezdağı volcanics (Akçadağ-Malatya)

Major, trace element and Nd-Sr isotopic data are presented for the Middle-Upper Miocene aged Kepezdağı volcanics in the western part of East Anatolian Volcanic Province (EAVP). Volcanics are represented as tuff, lapilli stone, agglomera and volcanic breccia at the bottom, and following basaltic, andesitic, dasitic and rhyolitics rocks. Rocks generally show microlytic porphyritic, glomeroporphic tand pilotaxitic textures. As whole rock major element contents, volcanics have ranging from 47,56 to 71,92 wt% SiO2 values, ranging from 0.55 to 3.68 wt% K2O values and ranging from 3.25 to 4.85 wt% Na2O values. In generally, these volcanics have sodic character with K2O/Na2O ratios ranging from 0,17 to 0,96. MgO contents are represented in a wide range beetween 0,29 and 8,49 wt%, and therefore the Mg numbers (Mg#) range from 20 to 64. Volcanics have geochemically calc-alkaline affinities and medium to high K contents. They are enriched different amounts of light rare earth elements (LREE) and heavy rare earth elements (HREE) and in the primitive mantle normalized diagrams, enriched by all elements from Cs to Ti, compared to the mid oceanic ridge basalts (N-MORB) and depleted from Ti to Lu. Initial 87Sr/86Sr values vary between 0,703347 and 0,708552, while initial 143Nd/144Nd values vary between 0,512338 and 0,512875. It is thought that the main magma forming the volcanics is derived from the enriched lithospheric mantle source and fractional crystallisation and relatively less crustal contamination play role in the evolutions of volcanics. Key Words : Kepez Volcanics, EAVP, Magmatism, Sr-Nd isotopes, LREE, HREE, Turkey