鄂西走马地区南华系大塘坡式锰矿床中硫同位素特征及其地质意义  

Characteristics of sulfur isotope and geological significance of manganese deposit from Datangpo Formation in Zouma Area,west Hubei Province

作　　者：赵军 吉雪峰 陈林 方喜林 曹文胜 冉中夏 皮道会 ZHAO Jun;JI Xuefeng;CHEN Lin;FANG Xilin;CAO Wensheng;RAN Zhongxia;PI Daohui(The Second Geological Brigade of Hubei Provincial Geological Bureau,Enshi 445000,Hubei,China;China University of Geosciences(Wuhan),Wuhan 430074,Hubei,China)

机构地区：[1]湖北省地质局第二地质大队,湖北恩施445000 [2]中国地质大学(武汉),湖北武汉430074

出　　处：《矿产勘查》2023年第4期599-607,共9页Mineral Exploration

基　　金：湖北省地质局科技项目——恩施走马地区南华系大塘坡式锰矿物质来源及成矿模式研究(KJ2020-6);湖北省地质勘查基金项目——湖北省鹤峰县走马地区铅锌多金属矿调查评价([2019]6);湖北省鹤峰县王家界矿区锰矿预普查([2017]37)联合资助。

摘　　要：近年来,鄂西走马地区发现了“大塘坡式”锰矿床,但是该区内锰矿的硫同位素相关研究尚未见报道。本文对鄂西走马地区的锰矿开展了详细的野外地质调查与钻孔岩心样品的硫同位素研究,结果表明:含锰岩系大塘坡组中黄铁矿δ34S值具有异常高值(33.7‰~46.2‰平均40.1‰)。但与贵州西溪堡、高地、湖南民乐、重庆小茶园、湖北古城等扬子地块周缘典型“大塘坡式”锰矿中黄铁矿δ34S值相比,研究区含锰岩系中黄铁矿δ34S值一般要低12‰~20‰,与黔东地区成锰盆地边缘相的黄铁矿δ34S数值相近,可能是研究区成锰盆地当时的水深比较浅,或者是位于一个大的成锰盆地的边缘相地带,导致水深较浅,含锰岩系厚度小,不利于走马地区大塘坡期大规模锰矿成矿。此外,研究区含锰岩系底部发育Sturtian盖帽碳酸盐岩(灰岩)等特征,也佐证研究区在大塘坡期为浅水沉积。In recent years,Datangpo type manganese deposit has been found in the Zouma area of western Hubei Province,but the study of the sulfur isotope of the manganese ore in the Zouma area has not been reported.In this paper,a detailed field geological survey and sulfur isotope study of bored fresh rock core samples of manganese ore in the area are carried out.The results show that theδ34S value of pyrite in Datangpo Group has an abnormally high(value of 33.7‰and 46.2‰,with an average of 40.1‰).However,compared with the typical Datangpo type manganese ore around Yangtze block,the pyriteδ34S value in the area is generally 12‰-20‰lower,and this is similar to pyrite of marginal faeies of manganese forming basin in eastern Guizhou.roughly located within the edge of manganese forming basin,which may indicate that the water depth of manganese forming basin was relatively shallow,or is located in the edge of a phase of a large manganese forming basin.The water depth is shallow and the thickness of manganite system is small,which is not conducive to large-scale manganese mineralization during the Datangpo period in the Zouma area.In addition,the characteristics of Sturtian cap carbonate(limestone)developed at the bottom of the manganese-containing system also confirms that the study area was shallow water sedimentary during the Datangpo period.

关 键 词：大塘坡式锰矿床 黄铁矿 硫同位素 鄂西走马地区 盖帽碳酸盐岩 

分 类 号：P597[天文地球—地球化学] P618.32[天文地球—地质学]