A LA-ICP-MS chronological study of basic volcanics in Baiyin orefield, Gansu, China

In this paper, LA-ICP-MS U-Pb isotope dating techniques were used to determine the metallogenic age，zircons from basic volcanic rocks in Baiyin orefield. Giving average 206Pb/238U ages of 465.0±3.7Ma，this age should be Midd1e Ordovician. meta acid volcanic rocks with their predecessors volcanic accurate isotope data(about 467.3±2.9 Ma和467.1±2.2 Ma)，therefor，this age is the formation time of meta basic volcanic rocks，Formation environment of meta basic volcanic rocks is Island arc- continental rift environment in Ordovician. The findings are of great significance in furtherr research on the tectonic evolution of the North Qilian orogenic belt,the formation environment of the Baiyin type massive sulfide deposits, and the ore prospecting directions.