云南贡山罗坡锡矿矿床地质特征及成因分析

Geological Characteristics and Genesis Analysis of Luopo Tin Deposit in Gongshan County,Yunnan Province

罗坡锡矿是滇西贡山—福贡成矿带上新发现的重要锡矿床,资源潜力良好,经济价值较大。通过翔实的野外地质调查及钻孔岩性观察统计证实,矿床的赋矿岩性为石炭系丹珠岩组第二段细晶白云质大理岩。矿区已发现的3个矿体群均产于大理岩的构造节理裂隙中,矿体均呈脉状、似层状产出,矿石矿物以锡石、褐铁矿、黄铁矿为主,脉石矿物以白云石、方解石为主,并含少量金云母、石英和电气石,矿石发育浸染状、细脉状和角砾状构造。矿(化)体严格受控于地层岩性及构造裂隙,尤以层间破碎带及顺层节理矿化最为富集。结合矿床成矿规律,认为矿床属火山-沉积改造型中低温热液锡矿床。

The Luopo tin deposit is a newly discovered important tin deposit in the Gongshan-Fugong metallogenic belt in western Yunnan.It has good resource potential and great economic value.Through detailed field geological survey and drilling lithology observation statistics,it is confirmed that the ore-bearing lithology of the deposit is fine-grained dolomitic marble in the second section of the Carboniferous Danzhuyan Formation.Three ore body groups have been found in the mining area,which are all produced in the structural joints and fissures of marble.The ore bodies are vein-like and stratoid.The ore minerals are mainly cassiterite,limonite and pyrite.The gangue minerals are mainly dolomite and calcite,and contain a small amount of phlogopite,quartz and tourmaline.The ore develops disseminated,veinlet and brecciated structures.The ore(mineralized)bodies are strictly controlled by the lithology and structural fissures of the strata,especially the interlayer fracture zone and the bedding joint mineralization.Combined with the metallogenic regularity of the deposit,it is considered that the deposit belongs to volcanic-sedimentary transformation type medium-low temperature hydrothermal tin deposit.