摘要
老挝万象盆地属于沙空那空盆地的次级盆地,沉积了厚层的钾石盐矿,而钾石盐中还存在着部分水不溶物,通过研究不同成钾区域的钻孔发现:水不溶物主要包括硬石膏、方硼石、白云母、石英、水氯硼钙石、碳酸盐矿物以及零散的黄铁矿,通过水不溶矿物在钻孔中的分布及组合特征发现,钾盐从析出到结束,水不溶物出现规律性特征:钾石盐含量越多方硼石含量也越多,而硬石膏且越少,并在钾石盐高峰期出现鲕粒方硼石,鲕粒方硼石分布表明成钾晚期沉积环境为动荡的浅水环境。水不溶矿物组合、形貌特征及硼同位素分析研究显示,在万象盆地成钾阶段,钾盐沉积不是一成不变的而是具有明显的阶段性,其过程可以分为石盐沉积晚期,钾盐沉积早期,钾盐沉积中期和钾盐沉积晚期等4个不同阶段,其中钾盐阶段中期为钾盐沉积高峰期。因此,水不溶物研究能够很好地反演钾盐沉积环境,可作为古蒸发岩沉积研究的重要指标。
The Vientiane Basin of Laos belongs to the secondary basin of Sakon Nakon Basin,where thick layer of potash are deposited,Through the study,it is found that the water-insoluble substances mainly include anhydrite,boracite,muscovite,quartz,hilgardite,carbonate minerals and scattered pyrite.According to the distribution and combination characteristics of water-insoluble minerals in boreholes,it is found that from the precipitation to the end of potash salt,the water-insoluble substances appear regular characteristics:the more potassium salt content,the more boracite content,the less anhydrite,and oolitic boracite appears in the peak period of potassium salt.the regular distribution of oolitic boracite shows the sedimentary environment is a turbulent shallow water environment.The mineral assemblage,morphological characteristics and boron isotope analysis of water-insoluble minerals show that potash deposits are not immutable,but have obvious stages.The process can be divided into four different stages:the stage of potassium salt out,the early stage of potassium salt stage,the middle stage of potassium salt stage,and the later stage of potassium salt stage.The middle stage of potassium salt stage is the peak period of potassium salt deposition.Therefore,the study of water-insoluble matter can be used as an important index for the study of paleopotash mechanism.
作者
唐启亮
张西营
苗卫良
李永寿
李雯霞
袁小龙
TANG Qiliang;ZHANG Xiying;MIAO Weiliang;LI Yongshou;LI Wenxia;YUAN Xiaolong(Key Laboratory of Comprehensive and Highly Efficient Utilization of Salt Lake Resources,Qinghai Institute of Salt Lakes,Chinese Academy of Sciences,Xining,Qinghai 810008,China;Qinghai Provincial Key Laboratory of Geology and Environment of Salt Lake,Xining,Qinghai 810008,China)
出处
《地质学报》
EI
CAS
CSCD
北大核心
2021年第7期2214-2224,共11页
Acta Geologica Sinica
基金
国家自然科学基金(编号41602086和42072101)项目联合资助的成果。
关键词
老挝万象盆地
方硼石
鲕粒方硼石
浅水环境
重要指标
Vientiane basin of Laos
boracite
oolitic boracite
shallow water environment
important index