内蒙古东南部矽卡岩型金属矿床的综合找矿模式

Integrated Ore-Prospecting Model for the Skarn Polymetallic Deposit in Southeastern Inner Mongolia

矽卡岩型金属矿床是内蒙古东南部重要的矿床类型,集中分布在黄岗梁—乌兰浩特铜多金属成矿带西南段,其代表性矿床有白音诺铅锌矿床和浩布高铅锌铜锡矿床以及黄岗铁锡矿床,是中国北方重要的铅锌矿和锡矿产地。总结、分析了此类型矿床中的代表性金属矿床的物化探勘查方法及其有效性,建立了矽卡岩型金属矿床地、物、化综合找矿模式。此类金属矿床多分布于黄岗—乌兰浩特铜多金属成矿带西南段二叠系大理岩或结晶灰岩夹层内,其受构造作用形成的复背斜轴部的虚脱部位是赋矿的有利场所。金属矿化特别是铅锌矿化与锰钙质辉石矽卡岩关系密切。矿床所在地区主要地层和酸性侵入岩类主要金属元素Cu、Pb、Zn、Ag、Sn的质量分数均大大高于背景值,并在矿带、矿化蚀变带和出露矿体上呈现高强度、衬度高、分带清晰的局部异常。成晕元素具有较好的分带性:矿体前缘晕为As、Sb、Hg、Pb、F;尾晕为Sn、W、Mo。矿体和矿化矽卡岩上常呈现高极化率、高磁力、高重力、低电阻率(三高一低)的组合异常特征。

The skarn polymetallic deposit,an important deposit type in southeastern Inner Mongolia,is mainly distributed in southwest section of Huanggang-Wulanhot polymetallic metallogenic belt.Baiyinnuo Pb-Zn deposit,Haobugao Pb-Zn-Cu-Sn deposit and Huanggang Fe-Sn deposit are representative skarn deposits in the area,and they are also important producing area for lead,zinc and tin in Northern China.The authors summarized and analyzed the effectiveness of geophysical and geochemical exploration method,and established comprehensive geological,geophysical and geochemical ore-prospecting models for skarn polymetallic deposit in the region.The ore bodies in these skarn deposits often are located in interlayer of Permian crystalline limestone or marble.The collapse part of compound anticline axis is favorable position for ore-forming materials precipitating by the tectonic movement.The mineralization,especially lead-zinc,has close relationship with manganese and calcium pyroxene skarn.The Cu,Pb,Zn,Ag,Sn contents in the strata and acid intrusive rocks near the ore district are much higher than the background value.In addition,the alteration zone associated with the mineralization and ore bodies exposed appear the geochemical anomalies with high-intensity,high-contrast and good-clear zoning.The element zoning shows that the geochemical halo in the front ore body are characterized by As,Sb,Hg,Pb and F,while the halo in the tail ore body by Sn,W and Mo.The ore bodies and mineralized skarn often display high polarization,high magnetic,high gravity and low resistivity（three high and one low） combination of anomalies.