滇西景谷曾家村铜矿地质特征及矿床成因新认识

Geological characteristics of Zengjiacun copper deposit and a new understanding of the deposit genesis in Jinggu City,West Yunnan

景谷曾家村铜矿床位于三江构造带中段的兰坪-普洱中-新生代盆地中南部。在野外勘探工作基础上,结合室内岩矿鉴定结果,对曾家村铜矿成矿地质特征进行了详细研究,并开展了与同构造位置的宋家坡铜矿矿石成分对比研究。研究结果显示:曾家村铜矿在矿体形态、矿石组构以及围岩蚀变方面既有典型层控沉积矿床特点,又有后期叠加改造特征,双重成矿作用特征明显。矿石成分对比分析结果显示:区域内三叠系火山岩对曾家村铜矿成矿金属有一定贡献,二者物源属性既有亲缘性又有继承性。综合矿床地质特征、矿石成分对比研究结果和区域构造演化史,认为曾家村铜矿床属典型的沉积-改造型铜矿床。曾家村铜矿床勘探成果、经验及成因认识的厘定,为整个兰坪-思茅盆地类似地区铜矿找矿打开了思路,拓宽了区域找矿前景。

Zengjiacun copper deposit in Jinggu City is located in the central-south of Lanping-Puer Meso-Cenozoic basin in the middle of Sanjiang tectonic belt.In this paper a detailed study is carried out about the metallogenic and geological characteristics of Zengjiacun copper deposit on the basis of field work and the result of indoor rock-mineral identification.The comparative study is also carried out on the ore composition of Songjiapo copper deposit at the same tectonic location.The research result of metallogenic and geological characteristics shows that Zengjiacun copper depoist has the features of both typical strata-controlled sedimentary deposit and late-stage superposed transformation in the formation process of orebodies,in the aspects of orebody shape,ore texture and surrounding rock alteration.The comparasion result of analysis data of ore composition indicates that the Triassic volcanic rock contributes to the metallogenic metals of Zengjiacun copper deposit in a certain degree.The source properties of Zengjiacun copper deposit and Songjiapo copper deposit are both affinity and inheritance.It is considered that Zengjiacun copper deposit belongs to a typical sedimentary-reformed copper deposit based on the geological characteristics and the results of ore composition comparison and the regional and geological structural evolution.The determination of the prospecting results,experience and genesis of Zengjiacun copper deposit has opened the way for the prospecting of copper deposits in the similar areas of Lanping-Simo Basin.The prospecting potential is widened in the region.