The Xiaoqinling area is located in the northern part of Qinling orogenic belt on the southern margin of North China Craton,and typical in regional tectonic movement,magmatic activity and mineral-ization.This area has experienced a long and complex magma-tectonic evolution since Archean with a va-riety of basic dikes formed.The dikes are associated with granites and gold veins in time and space or show cut across relationship.Zircon U-Pb isotope chronology of the basic dikes in the Fancha gold deposit area in the eastern Xiaoqinling has been studied.The zircons of the basic dikes are divided into magmatic zircons and inherited zircons.The isotopic age of the inherited zircons is 2430 Ma～2029 Ma basically co-incided with that of the basement Taihua Group indicating that some of the zircons were captured from Taihua Group,the magmatic zircon 1866 Ma～1803 Ma corresponding to Mesoproterozoic Era and coinci-ded with those of the widely developed volcanic rocks and some granites in the Xionger Group(Dujiayu pluton and Xiaohe Pluton).The volcanics and grantite are the product of the stretching and cracking of the North China craton in the Middle Proterozoic period.Both age of the inherited and granitic zircons are all formed in Proterozoic period.However large scale mineralization took place in Mesozoic era.There-fore,the genetic relationship between the basic dikes and the Mesozoic mineralization events is weak in time.
Fancha gold depositBasic dikesZircon U-Pb isotope chronologyXiaoqinling area
万方数据
维普
