内蒙古李清地银铅锌矿区成矿地质及地球化学特征

METALLOGENIC GEOLOGICAL AND GEOCHEMICAL CHARACTERISTICS OF THE LIQINGDI SILVER-LEAD-ZINC ORE DISTRICT IN INNER MONGOLIA

内蒙古李清地银铅锌矿区位于华北地台北缘大青山金银多金属成矿带东段,基底主要出露太古宇集宁岩群中深变质岩系,中生代叠加强烈的火山—岩浆作用,为多期叠加复合成矿作用地区。矿体主要分布在燕山期花岗岩与集宁岩群大理岩的外接触带上,岩浆沿断裂侵位,热液沿裂隙向围岩扩散并与围岩发生交代作用,导致铅锌银等沿断裂破碎带富集成有工业意义的矿体。在李清地一带圈出的甲类化探异常是以银为主的多金属矿致异常,异常元素有Ag、Pb、W、As、Au、Bi、Hg、Sb、Zn等,元素组合复杂,具明显的浓度分带和浓集中心。这种多元素异常显示出在该区寻找金银多金属矿产资源的潜力和充分的地球化学依据。

The Liqingdi silver-lead-zinc ore district of Inner Mongolia is situated in the eastern section of the Daqingshan gold-silver polymetallic ore-forming belt on the northern fringe of the North China Platform. Its basement is outcropped mainly as Achaean moder- ately-highly metamorphic sequence of the Jining Rock Group, with the superimposition of Mesozoic intense volcanism-magmatism, thus forming a multiply superimposed composite metallogeic area. Ore bodies are mainly distributed in the outer contact zone between the Yanshanian granites and the Jining Rock Group of marbles. Magma was emplaced along faults and thermal solution was diffused along fissures and replaced wall rocks, resulting in the enrichment of lead, zinc and silver in shatter zones to form industrially significant ore deposits. Grade - A geochemical anomalies delineated in Liqingdi area are caused by silver-dominated polymetallic ores with anomalous elements such as Ag, Pb, W, As, Au, Bi, Hg, Sb and Zn. Element associations are complex, showing distinctive concentration zon- ing and enrichment centers. This pattern of multi-element anomalies indicates that there exists potential for the prospecting of gold and silver polymetallic mineral resources in this area and that the geochemical indicators are relaiable.