The Study On Ore-forming Characters And Metallogenesis Of Gold Deposits In North Area Of Hebei Province

North area of Hebei province, lying between Siberia plate and North China plate,is an active belt in the geological evolution history, where tectonic deformation andmagmatism are all especially strong. Meanwhile through much extensive reformationof Hercynian and Yanshanian structural cycles, tectonic-deformation is complicatedand the strata is generally folded in the study area. So the study area has a veryfavorable geological conditions for forming gold deposits. According to statistics,about233gold deposits have been found in the area, including1super large deposit,2large ones,10middle-sized and27small ones.Based on the study of ore-forming material source, metallogenic type, depositcharacteristics and ore-bearing formation,we summarizes genetic types of golddeposits and discusses the correlations of ore-formation and ore-controllingfactors(strata, igneous rocks and structure). Combined with the regional tectonicevolution history, the paper also analyzes gold metallogenesis. Results are as follws:(1) On the spatial distribution, the area has3gold deposit concentratedregions: Xuanhua-Chicheng-Chongli area (northwest of Hebei Province),Chengde-Fengning-Longhua area and Zuihua-Qinglong-Kuancheng area (northeast ofHebei Province), expecially, the bordering area of the three countries of Xuanhua,Chicheng and Chongli is called as “Golden Triangle” of Hebei Province.(2) Based on the principle of metallogenesis first, combined with other factorssuch as deposit characteristics and ore-bearing formation, in the paper we divide thegold deposits up into the following4types:①metamorphic transformation type(such as Jinchangyu, Zhangquanzhuang, Zhailing, Jinjiazhuang, Dongping, etc.);②magmatic-hydrothermal type (such as Yuerya, Wazidian, Daxigou, etc.);③volcanic-subvolcanic hydrothermal type (such as Xiajinbaogou, Zhujiawa, Jiajiaying,etc.);④associated type (such as Niujuanzi, Shouwangfen, Caijiaying, etc.).(3) In this paper, we make a quantitative analysis for ore-controlling factors andsummarize corresponding ore-controlling regularity according to “ore-formingintensity and extensity (OFIE)”: Sanggan Group in lower-middle Archeozoic andDantazi Group in upper Archeozoic are regarded as the main source beds of golddeposits in the area; The host rocks are Precambrian formation, Hercynian andYanshanian granite. But up to now, none of large or middle gold deposit has been found in the Precambrian granite. Although with small outcrop area, Hercynian andYanshanian granite is the more important for the gold ore-forming. So among them,the most exploration potential one is Yanshanian granite; As for ore-controllingstructure, most ore deposits are restricted strictly by two groups of deep and largefaults (EW、NE-NEE trending), and the next is fold structure.(4) The paper divides the gold metallogenesis into:①metamorphic-magmaticsuperimposed type;②migmatization-remelting metasomatic hydrothermal type;③remelting magmatic hydrothermal type, respectively.