A NEW VIEWPOINT ON METALLOGENETIC DYNAMICS OF LIANHUASHAN AREA
Xu Guizhong1, She Hongquan1, Zhou Rui1, Yang Zhende1, Wang Yifen1, Yan Danping2, Yang Yi3
1. Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029; 2. China University of Geosciences, Beijing 100083; 3. Graduate School, China University of Science and Technology, Beijing 100039
The Lianhuashan area is located near the northern boundary of the North China plate,40 km west to the Chifeng city,where the gold metallogenesis is widely spread and results in the formation of Lihuashan gold deposits.The gold deposit is of quartz vein type,with the wall rocks consisting of metamorphic rocks of the Jianping Group in age of Late Archean.Our study indicates that the gold metallogenesis in the area occurred in Indosinian epoch,related to the tectono-magmatic activities of the Indosinian orogeny.The spatial distribution of a great amount of auriferious quartz veins being closely associated with diorite porphyry dykes,the data of stable isotope and geochemistry indicate that gold metallogenesis is related to the basic-intermediate magmatic activities,instead of the Yan shanian acidic magmatic activity.Based on the first discovery of ductile detachment zone in the crystallined basement,it is thought that the gold metallogenesis occurred in an environment of structural thermal-upheaval.A new metallogenetic dynamics,and based on which a model for the formation of gold deposits in Lianhuashan area are put forward,which can explain the dynamic process and formation of the gold deposit better.