Geochemical characters and tectonic significance of Late Paleozoic granitoids from Tekesi Daban, Western Tianshan

Granitoids of Tekesi Daban have been subdivided into two successions of the Kulesayi succession with age of 347Ma in the early Carboniferous period and the Qinaersayi succession with age of 291-292Ma in the early Permian period. By the research of geochemical features for the granitoids in this paper, some differences can be observed: the Kulesayi succession is characterized by A/CNK=1, K2O/Na2O=0.96, （Na2O+K2O）/Al2O3=0.66 and δ=3.2 on the average，whereas the Qinaersayi succession is characterized by A/CNK=1.05 and K2O/Na2O=1.17 on the average. The former is rich in Na2O, the latter is rich in K2O relatively. The Kulesayi succession is metaluminous rocks which is different of the latter (peraluminous granitoids). The Kulesayi succession which belongs to the calc-alkalic rock type is formed in the island arc tectonic setting and the Qinaersayi succession which belongs to the alkalic rock type is formed in post-orogenic episode.