LA-ICP-MS Zircon U-Pb Dating for Granite and Meta-Andesitic Tuff and Its Geological Significance——Case Study Supute Anticline in the Southern Margin of the Altay, Xinjiang

Situated in the middle part of the Central Asian Orogenic Belt(CAOB),the Altay orogenic belt(AOB) is an important metallogenic belt in China.Many economic deposits are distributed along southern margin of the AOB,e.g.Kaktal Pb-Zn deposit,Mengku iron deposit,Abagong iron deposit,and Tiemuerte Pb-Zn deposit,etc.,which all occur in the Kangbutiebao Formation stratum comprising low grade metamorphosed volcanic rocks.Using the LA-ICP-MS zircon U-Pb method,we obtain that the age of granite is 412.7±0.78Ma and that of andesitic tuff is 411.2±3.4Ma age,representing the eruption time of the granite and the meta-andesitic tuff at the Supute Anticline.This age indicates that an intense volcanic activity may occur in the early Devonian in the Supute Anticline in the southern margin of the Altay,suggesting an active continental margin setting during this time.They belong to the same event of product and have the same dynamic background with the extensive development of volcanic in this area.The Result provides important theoretical basis for the study of the Paleozoic tectonic evolution at Supute anticline and the Southern margin of Altay.