摘要
库车坳陷西段出露地表的盐丘可作为钾盐调查研究的重点对象,但针对地表盐丘开展的沉积学与地球化学相结合的系统研究较少,选取盐山口盐丘局部区域,通过露头剖面观察、手标本及薄片鉴定、岩盐包裹体及地球化学特征研究,分析其地质特征及找钾潜力,探索以地表岩盐为找钾研究对象的思路和方法。通过地层剖面观察、薄片鉴定、石盐包裹体研究,认为研究区地层较多的保留了原始层理、原生泥砾、原生包裹体等原始沉积状态和信息;石盐包裹体的均一温度明显低于长期深埋地下的石盐包裹体均一温度,表明岩盐层在形成后不久便在盐丘“浮力”及构造挤压的双重作用下持续上移;通过K/水不溶物、Br、Rb×10^(3)/K、B×10^(3)/K、泥质中Mn^(2+)/Fe^(3+)综合地球化学指标分析,识别出在较纯岩盐层发育阶段,成盐卤水具有相对浓缩特征。
The salt domes exposed on the surface in west of Kuqa depression can be a key focus of potassium salt investigation and research,but there is relatively little systematic research combining sedimentology and geochemistry on the surface salt domes.This article selects a local area of Yanshankou salt dome,analyzes its geological characteristics and potassium exploration potential through outcrop section observation,hand specimen and thin section identification,halite fluid inclusion and geochemical characteristics research,and further explores the ideas and methods of using surface rock salt as the research object for potassium exploration.Through observation of stratigraphic section,identification of thin sections,and study of halite fluid inclusions,this article believes that the study area has preserved many original sedimentary states and information such as original bedding,original clay-gravel,and original inclusions.The uniform temperature of halite fluid inclusions is significantly lower than that of long-term buried underground rock salt inclusions,indicating that the rock salt layer continues moving upwards shortly after its formation under the dual effects of salt dome buoyancy and tectonic compression.By analyzing the comprehensive geochemical indicators of K/water insoluble matter,Br,Rb×10^(3)/K,B×10^(3)/K,and Mn^(2+)/Fe^(3+)in clay,it is clearly recognized that in the development stage of relatively pure rock salt layers,saline brine has relatively concentrated characteristics.
作者
王凡
WANG Fan(Geology Institute of China Chemical Geology and Mine Bureau,Beijing 100101)
出处
《中国煤炭地质》
2024年第8期31-37,71,共8页
Coal Geology of China
基金
国家重点研发计划项目“中国钾盐矿产基地成矿规律与深部探测技术示范”(2017YFC0602800)
中国地质调查局地质调查项目“西部地区钾盐矿产远景调查评价”(DD20160054)。
关键词
沉积学
石盐流体包裹体
地球化学
盐山口盐丘
库车坳陷
sedimentology
halite fluid inclusion
geochemistry
Yanshankou salt dome
Kuqa depression
