柴达木盆地昆特依盐湖大盐滩矿区杂卤石沉积特征及成因浅论  

Sedimentary Characteristics and Origin of Polyhalite of Kunty Salt Lake Mine in Qaidam Basin

作　　者：刘铸[1,2] 高东林[1] 李斌凯[1] 袁小龙[1] 张岩[1,2] 李宝兰[1,2] 

机构地区：[1]中国科学院青海盐湖研究所,青海西宁810008 [2]中国科学院大学,北京100049

出　　处：《盐湖研究》2015年第1期30-37,共8页Journal of Salt Lake Research

基　　金：大盐滩钾矿区固体杂卤石矿分布及采矿技术研究项目(Y350121037)资助

摘　　要：昆特依盐湖是柴达木西北部一个次级断陷盆地,大盐滩矿区即位于其中。大盐滩矿区赋存有丰富的卤水钾盐矿床,同时也沉积了储量可观的固体钾盐矿,杂卤石是主要的固体钾盐矿物。大盐滩杂卤石主要分布于矿区中南部,面积约302 km2。杂卤石主要产出于石盐粒晶间及淤泥或粘土层中,呈薄层状分布,埋深12~65 m,钻孔岩芯化学分析结果揭示,K2SO4品位在2.43%~8.78%之间,平均3.95%。对不同赋存状态的杂卤石成因进行了初步探讨,推测杂卤石成因的两种可能性：1在盐湖沉积期间,当石膏和石盐沉淀后,浓卤水和硬石膏反应而生成杂卤石,并交代了硬石膏或结晶在石盐孔洞中。2在构造较为剧烈的升降期,由于钾易被粘土物质吸附,当进一步浓缩的卤水与粘土作用便以杂卤石的形式沉积下来,此类杂卤石原生沉积的特征明显。大盐滩固体钾盐资源成矿潜力大,查明其成因和分布规律可为开发大盐滩固体钾盐提供理论支持。Kunty Salt Lake is a secondary fault basin in northwest Qaidam, and the Kunty Salt Lake mine is located in it. Brine potash deposits are rich in the Kunty Salt Lake mine. At the same time, considera- ble reserves of solid potash are deposited in the mine. Polyhalite which was the primary solid potash min- eral and mainly distributed in central and southern of the mine had an area of 302 km2 and embeddeddepth of 12 m to 65 m. It mainly stored in crystalline grain halite or clay layer and distributed in thin lay- er. Based on drilling core chemical analysis results, the K2SO4 grades between 2.43% and 8.78% , the average is 3.95%. The paper preliminary discussed the causes of different occurrences of the polyhalite, and two possibilities causes were speculated. During the salt lake deposit, when the gypsum and halite were deposited, the reaction of high concentrations brine and anhydrite generated polyhalite, and re- placed the anhydrite or crystallized in halite holes. In the dramatic lifting period of tectonic movement, as the potassium is easily absorbed by clay material, when the further concentrated brine react with the clay, potassium will be deposited in the form of the polyhalite, and such polyhalite has significant primary sedi- mentary characteristics. In short, Kunty Salt Lake solid potash resources have high potential of minerali- zation. Finding out their causes and distribution can provide theoretical support for the development of Kunty Salt Lake solid potassium mineral.

关 键 词：大盐滩 杂卤石 固体钾盐 成因 

分 类 号：P619.211[天文地球—矿床学]