湖南宜章长城岭锑铅锌多金属矿围岩蚀变特征

摘要

Genetically related to the local Yanshanian granite porphyries,Changchengling Sb -Pb -Zn polymetallic deposit is a medium -low temperature hydrothermal deposit.This paper mainly discusses the features of the wall rock alteration in this area from such perspectives as geological characteristic,alteration types,distribution of various alterations and the geochemical characteristics of the altered rocks.The alteration of wall rocks in this deposit develops well with silicification,fluoritization,carbonation,chloritization,zeolitization and serpentinization,and there are also signs of skarnization,marbleization,micacization.Dolomitized or calcitized carbonatites are favorable ore -bearing rocks,and silicification is the most contributive alteration for ore-forming in the deposit.Alteration of wall rocks,which is controlled by relevant stratum lithologies,faults, granite porphyries and karst caves,plays an important part in the process of hydrothermal mineralization,and is a significant indicator for prospecting in this region.%长城岭锑铅锌多金属矿床是与燕山期花岗斑岩有关的中低温热液充填交代型矿床。主要从矿区地质特征、蚀变类型、蚀变分布特征及蚀变岩的地球化学特征等方面探讨其围岩蚀变特征。区内围岩蚀变发育，主要有硅化、白云石化、方解石化及菱铁矿化等，其次有萤石化、菱锰矿化、绿泥石化、沸石化及蛇纹石化等，局部发育大理岩化、矽卡岩化及云母化等。其中，白云石化、方解石化碳酸盐岩是有利的赋矿部位，而硅化是对研究区成矿最为有利的蚀变。研究区围岩蚀变受地层岩性、断裂、花岗斑岩及岩溶洞穴的综合控制，是长城岭锑铅锌多金属矿热液成矿作用的重要组成部分，也是重要的找矿标志。