黔西北赫章-威宁地区方解石矿床地质特征及控矿分析

Geological Characteristics and Ore Control Analysis of the Calcite Deposit in Hezhang-Weining Area,Northwest Guizhou Province

黔西北赫章-威宁地区方解石矿地处扬子地块西缘,位于六盘水断陷威宁北西向构造变形区垭都-蟒洞断裂带西南侧,属川滇黔成矿域黔西北垭都—蟒硐铅锌、萤石成矿带的组成部分,方解石矿的研究工作尚处于普查、详查阶段,本文通过赫章—威宁地区方解石矿开展系统地矿床地质、控矿分析研究,认为赫章-威宁地区方解石矿系燕山期构造热液事件形成产物;中-粗粒方解石矿矿体,与围岩表现出突变接触关系,指示为热液充填成因;局部发育的细粒方解石矿体(实际上是方解石大理岩),与围岩界线不清,系周围茅口组生屑灰岩经热液改造作用发生重结晶形成产物。

The calcite deposits within the Hezhang-Weining region of northwestern Guizhou Province are situated at the western margin of the Yangtze Block and the southwestern portion of the Yandu-Xiongdong fault zone,which is located within the northwestern tectonic deformation zone of Weining,in the Liupanshui fault depression.These deposits constitute a component of the Yandu-Xiongdong lead-zinc and fluorite metallogenic belt,which falls within the Sichuan-Yunnan-Guizhou metallogenic province.This paper presents a comprehensive analysis and investigation of the calcite deposits in the Hezhang-Weining area,focusing on deposit geology and ore control factors.It is inferred that the calcite deposits in the Hezhang-Weining area are the result of the Yanshanian tectonic hydrothermal activity.The medium-coarse-grained calcite ore bodies exhibit an abrupt contact with the host rock,suggesting an origin of hydrothermal filling.The locally occurring fine-grained calcite ore bodies(effectively calcite marble)possess an indistinct boundary with the surrounding rock,and are considered to be the outcome of recrystallization of the adjacent Maokou Formation clastic limestone due to hydrothermal alteration.