中国低温热液矿床集中分布区的一些地质特点  

SOME GEOLOGICAL CHARACTERISTICS OF CONCENTRATED DISTRIBUTION AREA OF EPITHERMAL DEPOSITS IN CHINA

作　　者：李朝阳[1] 

机构地区：[1]中国科学院地球化学研究所

出　　处：《地学前缘》1999年第1期163-170,共8页Earth Science Frontiers

基　　金：中国科学院"九五"重大项目

摘　　要：通过对我国西南地区低温热液矿床集中分布区的区域地质背景（包括基底、盖层、构造与地球物理特征）和一些低温热液矿床的地质特征的研究，重点对低温热液矿床集中分布在中国西南地区的条件进行了初步探讨。提出：（１）巨厚的地壳使温度高的地幔对容矿地层的面型影响不强烈，只是在一些切壳的深大断裂附近形成一些较高的地温场、小岩体和岩脉；（２）区内元古代基底区域变质作用不强，经受的温度、压力都不是很高，致使元古界岩石中的成矿元素没有大量被结晶（变质）分异作用排出，因而其成矿元素丰度较高；（３）新元古代—古生代巨厚的沉积盖层显示出该区长时间、大面积稳定下沉，岩浆活动（特别是侵入活动）不强烈；（４）盖层中大量含碳质细碎屑岩与碳酸盐岩石相间出现的岩性组合反映了海进海退、氧化还原的沉积环境变化，有利于成矿元素沉淀富集；（５）很多低温热液矿床成矿物质都来自深部。Through the study on the regional geological setting of the concentrated distribution area of epithermal deposits in Southwest China, including the characteristics of the basement, the cover, structure and geophysics, and some geological features of some epithermal deposits, this paper concerns mainly with the condition which leads to the concentrated distribution of the epithermal deposits in Southwest China. It suggests that (1) the mantle with high temperature does not have a great influence on the host strata because of the huge thickness pertaining to the crust but some high geotemperature fields, small rock masses and dikes may develop in the vicinity of some deep crust cutting fractures; (2) the regional metamorphism with lower pressure and temperature of Proterozoic basement is not strong so that ore forming elements can not be discharged greatly by metamorphism. The abundance of ore forming elements in the rocks of Proterozoic group is higher; (3) the huge thick late Proterozoic Paleozoic cover shows the long time and great area stable sedimentation and weak magmatic activities especially the intrusions during Caledonian Yanshan age; (4) a large amount of carbonaceous fine clastic rock and carbonate rock occur alternately, indicating the changing of sediment environment of progression regression and oxidation reduction which is advantageous to the precipitation and enrichment of the ore forming elements; (5) the ore forming substances of many epithermal deposits come from the deep. The thick cover is advantageous for the temperature to lower slowly in the ore forming process, so leads to the formation of many epithermal deposits.

关 键 词：低温热液矿床 集中分布区 热液矿床 地质特点 

分 类 号：P611.1[天文地球—矿床学]