贵州威宁地区峨眉山玄武岩型自然铜-辉铜矿矿床的成矿前景

DISCUSSION ON THE ORE-FORMING PROSPECTING OF THE EMEISHAN BASALT-TYPE NATIVE COPPER-CHALCOCITE DEPOSITS IN THE WEINING DISTRICT OF GUIZHOU PROVINCE,CHINA

贵州威宁一带产于峨眉山玄武岩中的自然铜-辉铜矿矿床(点)经过几十年研究,但在找矿勘探方面一直难以突破。本文从矿床地质特征、成矿物质来源出发,讨论了与成矿规律和成矿远景,认为矿化受夹层和断裂双重控制,成矿以后期热液改造作用为主。与基伟诺型矿床相比,玄武岩厚度不大及不连续分布、陆相地表喷发、埋藏深度不大、缺少成矿流体汇聚的构造条件是形成大矿的不利因素。在峨眉山玄武岩分布区内,玄武岩厚度巨大、构造应力集中的地区有可能找到中型规模以上的矿床。

Some important progress in the mineralization theory of the Emeishan basalt-type native eopper-chalcocite deposits （ore occurrences）in the Weining district of Guizhou Province has been made in the past several decades of years. However, it is difficult to make a break through in prospecting-exploration. In this paper, some geologicaland geochemical questions concerning the mineralization role and mineralization prospect were addressed. ＇lhe copper mineralization is eontmlled by both the tuffaceous-sedimentary intercalation andfault. Many geological and geochemical characteristics do not support the volcano-magmatic hydrothermal mineralization origin, and the deposits were of epithermal origin. As compared with the Keweenaw-type copper deposits in U. S. A., factors such as the limited basalt volume and land surface eruption of the basalt in the Weining area of Guizhou Province are disadvantageous for the formation of the large deposit. The focus of prospecting for this type of ore deposits should be put on western Yunnan and Sichuan, where there are widely spread basahs and cover strata of great thickness, with concentrative tectonic stress and magmatic intrusion at depth.