U-Pb Dating of Detrital Zircons from the Kanas Group in Northern Altay and Its Geological Significance

The Kanas Group is consists of thick epimetamorphic terrigenous clasolite, which occurs widely in northern Altay. In this paper, the samples of zircon isotopic dating and rock geochemicalanalysis have been collected systematically. The geochemical results show that these clasticsedimentaries were sourced from passive continental margin.The U-Pb dating of detrital Zircon from the Kanas Group yield the youngest magmatic Zircon age of 545.8±3.7 Ma, defining that the lower boundary of the Kanas Group can be delimit as Sanian. But the older Zircon ages are 858±13 Ma and 1 800-1 983 Ma, which belong to Proterozoic era,indicating the existence of Precambrian continental crust basement.