宁夏石记场石膏矿岩矿石类型及成因分析

Ore Types and Genetic Analysis of Gypsum Rocks in Shijichang,Ningxia

石记场石膏矿位于宁夏盐池县青山乡,是宁夏重要的石膏产区,现已打造成中国西北石膏产业基地。为探究石膏矿岩矿石类型及成因,在对矿区岩矿石类型进行系统鉴定的基础上,将矿石分为块状石膏、泥质石膏、砂质石膏3种自然类型,围岩分为砂岩和泥岩2种。再结合微观矿物成分、含量、结构构造特征将块状石膏细分为5小类,分别为细晶石膏岩、中细晶石膏岩、中粗晶石膏岩、巨晶石膏岩、不等晶石膏岩。岩矿石的特征能充分反映出矿床形成时的岩相古地理、成矿物质来源、气候条件及后期保存条件,并确定了石记场石膏矿床类型为内陆蒸发湖盆沉积型。研究结果可为石记场地区石膏矿的找矿勘查提供参考和借鉴。

Shijichang gypsum mine is located in Qingshan Township,Yanchi County,Ningxia.It is an important gypsum production area in Ningxia,and has become a gypsum industry base in northwest China.In order to explore the types and genesis of gypsum ore,based on the systematic identification of rock and ore types in the mining area,the ore is divided into three natural types:block gypsum,argillaceous gypsum and sandy gypsum,and the surrounding rock is divided into sandstone and mudstone.Combined with the mi⁃cro mineral composition,content and structural characteristics,the massive gypsum is divided into five cate⁃gories,namely fine crystal gypsum rock,medium and fine crystal gypsum rock,medium and coarse crystal gypsum rock,giant crystal gypsum rock and unequal crystal gypsum rock.The characteristics of rock and ore can fully reflect the lithofacies palaeogeography,ore-forming material source,climatic conditions and late preservation conditions when the deposit formed,and determine the Shijichang gypsum deposit type is inland evaporative lake basin sedimentary type.This conclusion can provide reference for the prospecting and exploration of gypsum deposits in Shijichang area.