TURKISH JOURNAL OF EARTH SCIENCES, vol.18, no.1, pp.1-27, 2009 (SCI-Expanded)
Hasandag and Erciyes stratovolcanoes, which are the two important stratovolcanoes in Central Anatolia, erupted volcanic products with both calc-alkaline and alkaline compositions, although the calc-alkaline activity is more widespread. There are three stages of geochemical evolution in the history of the Hasandag stratovolcanic complex: (1) Kecikalesi tholeiitic volcanism, (2) Hasandag calc-alkaline volcanism, and (3) Hasandag alkaline volcanism. The geochemical evolution of Erciyes volcanic complex also exhibits three distinct evolutionary stages: (1) Kocdag alkaline volcanism, (2) Kocdag calc-alkaline volcanism and (3) Erciyes calc-alkaline volcanism. The volcanic rocks from both suites show enrichments in LREE relative to HREE. The rocks as a whole show enrichments in large ion lithophile elements (LILE) relative to high field strength elements (HFSE) in N-MORB normalized multi-element diagrams, although the thoeliitic and alkaline rocks have less pronounced effects of HFSE/LILE fractionation comparing to the calc-alkaline rocks.