| The Qinling Mian(Mianxian)-Lue(Lueyang)-Ning(Ningqiang) triangle block lying in the northwest Yangtz plate is a important ore serried area,there occur Jianchaling large gold deposit,Tongchang copper deposit and Dongouba Pb-Zn-Au-Ag polymetallic massive sulfide deposit Based on systemic studying the regional geological evolution, geological constitute ,structure constitution and their relation with the ore formation,distribution of the main metallogenic belt,characteris of the ore fabrication, geological and geochemical characteristics of the prototype deposits,genesis of the deposits and mechanism of the ore formation , the author summarize the zone regularities and point out the ore prospecting According to the regional constitute and geological datum,the Mian-Lue-Ning block has undgone processes with rifting and accretion of paleo-basement during late Archaean to early -middle Proterozoic, piece togather in late Proterozoic, lifting togather during Caledonian and Indosinian-Yanshanian orogenics,and it has characteristics of alert crust-mantle impact, complicated tectonic movememt, substance-energy exchanging frequently,and mineralization notability The block is a complex one which is made up from new Archaean Yudongzi group crystalline basement,Proterozic Daan and Hejiayan rock group, Bikou rock group, Sinian, Devonia-Canboniferous cover,and ultrabasic rock, basic rock,and mid-acid magama formed during different period and in different tectonic circumstances; which are "welded" by paleo-basement structure belt,slip structure belt between the basement and the cover The Yudongzi granite-greenston terrain ,middle and upper Proterozic Bikou groupspilite-keratophyre formations,and basic, ultrabasic rock from deep sources are main banded host rock and ore-bearing formations; paleo-basement structure belt, boundary structure belt which moved frequently with magamatic hydrothermal are outer dynamics that cause the ore element in basement removed and they are important places the ore fluid to rich and deposit Based on characteristics of the basement rock assemblage and their space distribution, structctural framework built up by relationship of the main components and types of ore genesis,features of ore assemblage and ore space distribution in the block,three metal ore bands are marked out,they are the northern Au-Ni,Au-Fe ore band;the middle Au-Ag-Cu-Pb-Zn-Ba polymetallic ore band and southern Cu-Au ore band Couplings or associations in ore band set up various ore forming system,so the orebodys or ore-bearingbodys have sumilar ore types, element association and ore formation prosess, and they have characteristics of space distribution in group or belt Studying geological and geochemical characteristics of Tongchang copper deposit, Donghuanggou Donggouba, Pb-Zn-Au-Ag polymetallic massive sulfide deposits in the middle ore band,the author thought that the main ore formation substance of Tongchang copper deposit came from ocean volcano in middle and upper Proterozic Bikou rock group,which undergoing magmatic reformation during Hercynian,especially the structure reformation during Indosinian-Yanshanian,then formed the magmatic-structure reformed type copper deposit Donghuanggou, Donggouba Pb-Zn-Au-Ag polymetallic massive sulfide deposits formed with the ocean volcanic outbreaking and volcanic sendimentation prosess,which had features of volcano sedimentary ore deposit, Donggouba deposit formed in volcanic rent,but Donghuanggou deposit formed near volcanic orifice Geological and geochemical characteristics of Jianchaling gold deposit Jindongzi gold ore plot in the northern ore band reflected that ore formation substance of Jianchaling gold depositcame from Jianchaling ultrabasic rock, Jianchaling ultrabasic rock which was reformed intensely by ductile-brittle fault had been of alteration,ore formation elements were relieved and migrated,then joined into the ore formation fluid,ultimately situated near the fault belt between ultrabasic rock and Sinian dolomite... |
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