陕西镇坪牛头店黑色岩系区Ag异常成因探讨  

The Causes of Ag Element Geochemical Anomaly for Black Rock Series in Niutoudian Area,Zhenping County,Shaanxi Province

作　　者：李普涛[1] 温志亮[1] 李宗会[1] 

机构地区：[1]中国地质调查局西安地质调查中心,陕西西安710054

出　　处：《西北地质》2015年第4期141-147,共7页Northwestern Geology

基　　金：陕西省地勘基金项目(61200901017)

摘　　要：陕南北大巴山地区黑色岩系发育,其中圈定出了一批Ag、Mo、V、As、Sb等多元素综合异常,且Ag元素异常规模大、强度高,具分带,但银矿找矿工作一直没有得到突破。在对区内黑色岩系及新发现银矿(化)体分析研究的基础上,对Ag元素异常成因进行了探讨,认为:①下寒武统鲁家坪组(黑色板岩、硅质岩)是Ag元素的初始富集层位,该套黑色岩系中Ag与Mo、V元素为同组元素,且富集过程一致,显示其富集过程具深海冷水沉积特征。②次生淋滤作用是Ag元素叠加富集的主要成矿作用,在一些Ag异常区内易发生淋滤作用的有利地带,会形成次生淋滤型的银矿床。The black rock series are well developed in North Daba mountains of Southern Shaanxi, where the geochemical anomalies of Ag, Mo, V, As and Sb elements have been delineated. Although the geochemical anomalies of Ag element often have largescale and high strength, with the characteristics of a ring shaped, but the no breakthrough. On the basis of analyzing and researching prospecting work of Ag deposit has the newly discovered silver body in black rock series of this area, the cause of geochemical anomalies of Ag elements has been discussed in this paper. The results suggest that, ①The LujiapingFormation of Lower Cambrian （black shale, siliceous rocks） is the initial concentration of Ag element. Ag serves as the same group with Mo and V elements in the black rock series, all of them had experienced the same enrichment process, showing the deposition characteristics of deep-sea cold water. ② Secondary leaching is the main mineralization for stacking and enrichment of Ag element. The secondary leaching were easily happened in some favorable zones within the geochemical anomalies of Ag element to form the silver deposit.

关 键 词：北大巴山 镇坪县 黑色岩系 化探异常 

分 类 号：P618.51[天文地球—矿床学] P618.61[天文地球—地质学]