碾子沟金红石矿床蚀变作用的基本特征及其与成矿的关系

THE BASIC CHARACTERS OF ALTERATION AND ITS RELATIONSHIP WITH ORE-FORMING IN NIANZIGOU RUTILE DEPOSIT

矿区蚀变岩分为细晶直闪(片)岩、粗晶直闪(片)岩、绿泥片岩及滑石(片)岩4大类;一般绿泥片岩位于蚀变带边部,滑石(片)岩位于中部,直闪(片)岩位于二者之间;含矿岩石主要为直闪(片)岩、次为滑石(片)岩,绿泥片岩富含铁质矿物。蚀变作用过程划为细晶直闪石化、粗晶直闪石化、绿泥石化、滑石化及斜长石化5个阶段,前4个阶段分别形成了上述4类蚀变岩,后一阶段仅形成了矿物细脉;形成金红石的主要为滑石化、次为粗晶直闪石化及细晶直闪石化,斜长石化形成的甚微。高温热液使深部及围岩中的钛向成矿部位富集,蚀变过程中铁与钛的分离及滑石化在直闪(片)岩等上的叠加,是主要成矿作用。据蚀变岩分布规律分析,碾子沟地区应有较好成矿远景。

The altered rocks in these mining area can be divided into four categories, which are fine-crystalline anthophyllite schist, coarse-crystalline schist, chlorite schist, occurring different part of alteration zone and play a different role in ore-forming. Generally, the chlorite schist exists in the edge and talc schist in the middle, among of them is anthophyllite schist, the anthophyllite schist is the principal ore-forming rocks, then talc schist, chlorite schist riched in iron. The alteration process has five stages, the first four of them are fine-crystalline anthophyllization, coarse-crystalline anthophyllization, on regular distribution of altered rocks, there is a prospect place for rulite mineralization in Nianzigou area.