What processes control the genesis of absarokite to shoshonite-banakite series in an intracontinental setting, as revealed by geochemical and Sr-Nd-Pb isotope data of Karadak Stratovolcano in Central Anatolia, Turkey


ÇOBAN H., Karsli O. , CARAN Ş., YILMAZ K.

LITHOS, cilt.324, ss.609-625, 2019 (SCI İndekslerine Giren Dergi) identifier identifier

Özet

The Latest Cenozoic absarokite to shoshonite-banakite series (ASB) samples were discovered in the Karadag stratovolcano (KS) which erupted in the Karaman basin in Central Anatolia, Turkey; and has a spatially close association with major strike-slip faults and pull-apart basins. The KS are made up of adakitic andesite and dacite, with minor ASB lava flows. Here, we present integrated data of mineral chemical, whole rock major and trace element, Sr-Nd-Pb isotope and conventional K-Ar age of the ASB series rocks in Central Anatolia. The rocks were dated by conventional K-Ar dating method in old of 393 +/- 153 ka. The series are comprised of slightly differentiated absarokite and more fractionated shoshonite-banakite lava flows. The OI-normative absarokites contain phenocrysts of olivine and diopside, whereas the Hyp-normative shoshonites-banakites are made up of olivine, diopside, phlogopite, K-feldspar and plagioclase. Both series have a potassic nature and near-primitive character with high MgO (5-11 wt%) and Mg# (62 to 74). The overall samples were characterized relatively by the enrichment in large ion lithophile elements (LILE) and the depletion in high field strength elements (HFSE), with insignificant negative Eu anomaly. They possess homogeneous and unradiogenic Sr and Nd isotopic compositions, marked by Sr-87/Sr-86(t) = 0.70507 to 0.70540 and epsilon(Nd)(t) =0.6 to +12. T-DM(,) and Pb isotopic ratios tending towards the EMIT mantle end-member.