摘要
罗布泊是世界上最大的单体硫酸盐型液体钾盐矿床,对于其矿床成因一直存在争议.基于大量盐泉、地下潜水及地表水的化学实测数据,从水文化学的角度探讨罗布泊富钾卤水矿床成因.结果表明,矿区富钾卤水钠氯系数为0.76~1.24,钾氯系数为38.58~60.49,主体表现为溶滤型卤水特征,指示有其他来源卤水混合参与成矿;首次在罗布泊东部断裂带发现Ca-Cl型卤水,具有典型的富Na^(+)、K^(+)、Ca^(2+)、Cl^(‒),贫HCO_(3)^(‒)、CO_(3)^(2‒)、SO_(4)^(2‒)特征,指示罗布泊有深部热液流体补给.在成矿过程中,Ca-Cl型卤水通过“兑卤”效应,直接改变原有成矿卤水成分及结晶路线,使其矿化度升高,而且富K、Na.改造后的富“钠”卤水与前期生成的石膏(CaSO_(4)·2H_(2)O)反应,生成钙芒硝(Na_(2)Ca(SO_(4))_(2)·2H_(2)O),并赋存于多孔的钙芒硝晶间,形成超常高矿化度富钾卤水矿床.
Lop Nor is the largest single sulfate-type liquid potash deposit in the world,and the genesis of the deposit has been controversial.In this paper,the genesis of potassium-rich brine deposits in Lop Nor is discussed from the perspective of hydrochemistry,based on a large number of measured chemical data of salt springs,underground phreatic water and surface water.The results show that the sodium-chlorine coefficient of potassium-rich brine is 0.76-1.24,and the potassium-chloride coefficient is 38.58-60.49.The main body of the brine shows the characteristics of dissolving-filtering brine,indicating the mixing of brine from other sources.It is the first time that Ca-Cl type brine is found in the eastern fault zone of Lop Nor basin and Dawadi,which shows typical characteristics of enrichment in Na^(+)、K^(+)、Ca^(2+)、Cl^(‒)and depletion in HCO_(3)^(‒)、CO_(3)^(2‒)、SO_(4)^(2‒),indicating deep hydrothermal supply in Lop Nor Basin.In the ore-forming process,the Ca-Cl type brine can change the composition and crystallization route of the original ore-forming brine directly through the effect of“mixing brine”,so that its mineralization degree is increased,and it is rich in K and Na.The reformed“sodium-rich”brine reacted with gypsum(CaSO_(4)·2H_(2)O),and formed glauberite(Na_(2)Ca(SO_(4))_(2)·2H_(2)O),which existed among the porous glauberite crystals,forming super-high salinity potassium-rich brine.
作者
马黎春
王凯
张瑜
汤庆峰
孙明光
Ma Lichun;Wang Kai;Zhang Yu;Tang Qingfeng;Sun Mingguang(Ministry of Natural Resources Key Laboratory of Metallogeny and Mineral Assessment,Institute of Mineral Resources,Chinese Academy of Geological Sciences,Beijing 100037,China;Beijing Center for Physical and Chemical Analysis,Beijing 100089,China)
出处
《地球科学》
EI
CAS
CSCD
北大核心
2022年第1期72-81,共10页
Earth Science
基金
中央级公益性科研院所基本科研业务费专项资金(No.JYYWF2018)
中国地质调查局项目(No.N1611)。
关键词
罗布泊
钾盐矿床
富钾卤水
富集机理
卤水化学
矿床学
Lop Nor
potash deposit
potassium-rich brine
enrichment mechanism
brine chemistry
mineral deposit
