Carbonate Strata And Their Constraints On The Pb-Zn-Ag Polymetallic Deposit In South Zhangjiakou

Zhangjiakou District is located in the north margin of Huabei platform,and it is one of the concentrated distributing areas for Pb-Zn-Ag polymetallic ore resources in Hebei province.We have found Caijiaying and Qingyanggou Pb-Zn-Ag polymetallic deposits in north Zhangjiakou,which is located in Inner Mongolian Axis.Carbonate strata in Middle-Upper Proterozoic period and magmatic in yanshan period was well developed,tectonic movement was intensive,they created advantageous geological conditions for the strata-bound carbonate type and the skarn type Pb-Zn-Ag polymetallic deposits.Carbonate strata and their constraints on the Pb-Zn-Ag polymetallic deposit is an outstanding issue,so there was no breakthrough in ore prospecting for a long time.In order to know the characteristics of the deposits clearly,classfied the type of deposits accurately, summarize metallogenic regularity systematically and provide prospecting direction effectively, we will study carbonate strata and Pb-Zn-Ag polymetallic deposits in south Zhangjiakou,based on its metallogenic condition and relevant information.The study area including Xuanhua District,Chicheng county,Huailai county and Zhuolu county.It is located in the yanshan rift belts of the secondary structural units in the north margin of Huabei platform.On the basis of fundamental geological research in south Zhangjiakou,we know regional magma activation, tectonic evolution and stratigraphic distribution.We analysis Liangjiagou deposit which is hosted by the wumishan dolostone strata and Mengjiayao deposit which emerges at the contact place between the dolomite of wumishan strata and intermediate-acid rock of Yanshanian epoch. According to rock(ore)slices identification and geochemical tests of samples by using macroelement,trace and rare earth element in doors,we are preliminarily identifing the type of Liangjiagou deposit is MVT lead-zinc deposit and Mengjiayao deposit is skarn polymetallic deposit.At the same time we choose three geochemical profiles in carbonate strata, analysing depositional environment and ore-bearing potential of this strata.Accordingly we could determine the relationship between Pb-Zn-Ag polymetallic deposit and carbonate strata in Middle-Upper Proterozoic.The dolomite of gaoyuzhuang and wumishan strata have a close relationship to Pb-Zn-Ag polymetallic deposit,especially the rubble dolomites,because its holes provide space for the ore-forming hydrothermal solution.Our work provide theoretical basis for the prospecting of Pb-Zn-Ag polymetallic deposit in south Zhangjiakou.