湘西地区黔阳次级成锰盆地锰矿地质特征及找矿潜力分析—以大岩坳向斜南东翼为例

湘西地区黔阳次级成锰盆地位于扬子陆块东南缘,构造位置上属雪峰山板内造山带南-东端。盆地内锰矿床为具有“内源外生”特征的南华系中统大塘坡组,处于大岩坳向斜的东南翼的半局限浅海盆地中,为沉积变质型锰矿床,据笔者工作资料矿体受大塘坡组黑色含锰炭质板岩控制,亦受加里东期构造控制,矿体呈层状、似层状及串珠状.物相分析表明矿石矿物近地表主要为氧化锰矿,地表10m以下为菱锰矿。本文通过对典型矿床照洞锰矿矿区的矿床地质特征、古构造环境综合分析,推测该区具有较大的找矿潜力。

Geological features and prospecting potential of the secondary manganese mineralization basin in the Qianyang area, Western Hunan Province: An example of southeast limb of the Dayanao syncline

The secondary manganese -forming basin in the Qianyang area, western Hunan is located in the southeastern margin of the Yangtze block, southeast end of the Xuefengshan intraplate orogenic belt. Its Datangpo Formation of the Middle Nanhuan System, where a manganese deposit is present, is characterized by "endogenous and exogenetic", which lies in a half limited shallow sea basin on the southeast wing of the Dayanao syncline, being of the sedimentary metamorphic type. Data available suggest that its ore bodies are controlled by the black manganese-bearing carbonaceous slate of Datangpo Formation and the Caledonian structure. These ore bodies are layered, quasi- layered and beaded. Physical phase analysis shows the ore minerals are mainly manganese oxide near the surface, and magnesite is 20m beneath the surface. Based on the comprehensive analysis of ore deposit geological characteristics, lithofacies paleogeography and paleotectonic environment of the typical Zhaodong mine nearby the manganese deposit, it is inferred that this area has a major ore-search potential.