INTERNATIONAL GEOLOGY REVIEW, cilt.50, sa.10, ss.931-947, 2008 (SCI-Expanded)
Tavsanli Zone in northwest Turkey is intruded by many Late Cretaceous to Eocene (91-45 Ma) calc-alkaline granitoids, of which the Gunyuzu pluton in the Eskisehir region is the least studied. The Gunyuzu rocks are high-K, calc-alkaline (I-type) intrusions. and are comprised of diorite, granodiorite, granite, and granite porphyry. Typical minerals are plagioclase, K-feldspar, quartz, biotite, hornblende and Fe-Ti oxides. Chondrite-normalized REE patterns for the Gunyuzu rocks are moderately fractionated and have small negative Eu anomalies. They are enriched in LILE and LREE relative to HFSL, showing characteristics of arc-related granitoids. Low values of molar K2O/Na2O, Al2O3/(FeO+MgO+TiO2). and (Na2O+K2O)/(FeO+MgO+TiO2) ratios demonstrate that the Gunyuzu magma(s) were produced from mafic lower crustal rocks.