TEMPORAL RELATION OF KARAKAYA (ESKISEHIR) GRANITE WITHIN THE FELSIC INTRUSIVE ROCKS OF NW ANATOLIA: GEOLOGY AND PETROLOGY

The granite and granodiorite of NW Anatolia are represented the Tertiary magmatic products of the Sakarya and Anatolide collision rock unit after the closure of Northern branch of Neo-tethyan ocean. These granitic rocks have medium K content, calcalkaline character and they plot on collision related volcanic arc granite area on the tectonic discrimination diagram.

Karakaya granite of NW Anatolia crops out at the eastern part of the region is differing from the other granitic rocks in the view of geology, petrography and geochemistry. Karakaya granite has holocrystalline granular texture and mainly composed of quartz, orthoclase, oligoclase, biotite, tourmaline, ± allanite, ± zirkon. Karakaya granite characterise by the presence of nepheline bearing enclaves as angular to sub angular in shape and ranging from 1 cm upto 50 cm in size. It has calkalkaline, high K content, schoshonitic magma nature and they plot on syn-collision granite area on the tectonic discrimination diagram.

ORG normalized elemental patterns of Karakaya granite reveal that they are enriched in LREE (Rb, K, Ba, Th) with respect to HFSE (Zr, Hf, Sm,Y). LREE contents show a clear enrichment with respect to HREE. Geology, petrography and geochemical features of Karakaya granite reveal a partial melting of crustal components with a mantle signature nature.