云南省勐海县布朗山锡矿矿床成因及找矿标志分析

Analysis of Genesis and prospecting criteria of Brongshan tin deposit in Menghai County, Yunnan Province

布朗山花岗岩体出露广泛,属印支期早期岩体,相带表现不清,但岩体中常见围岩残留体和残余层理,麻理构造,在边缘带具混染作用,部分边缘带形成数十米至数百米宽的混染花岗岩带。从已发现的锡矿(化)体分布位置看,几乎沿着岩体接触带分布,严格受其控制,而从矿化型式、矿石类型看又属锡石—角岩型,也离不开岩体接触带之概念,说明锡矿与花岗岩关系非常密切。从区域上看花岗岩之围岩—澜沧群片岩并不是含锡层位。因此,矿物质来源可能就来源于花岗岩,花岗岩是成矿母岩。

The Brownshan granite body is widely exposed and belongs to the early Indosinian rock mass with unclear facies zones. However, the residual bedding and marbling structures of surrounding rocks are common in the rock mass, which have mixed effect in the margin zone. Some of the margin zones form mixed granite zones of tens of meters to hundreds of meters wide. From the distribution position of discovered tin ore bodies, they are almost distributed along the contact zone of rock mass and strictly controlled by it. From the mineralization type and ore type, they belong to cassiterite-hornblende type, which can not be separated from the concept of rock mass contact zone. This shows that tin ore is closely related to granite. Regionally, the surrounding rock of granite - Lancang Group schist is not TIN-BEARING horizon. Therefore, the source of minerals may come from granite, which is the parent rock of mineralization.