川东北地区三叠系聚盐成钾机制及富集模式  

Salt Accumulation,Potassium Formation Mechanism and Enrichment Model of Triassic in Northeast Sichuan Basin

作　　者：张兵[1] 刘威[1] 杨凯[1] 裴文彬 张赛民[1] 肖威 Zhang Bing;Liu Wei;Yang Kai;Pei Wenbin;Zhang Saimin;Xiao Wei(Ministry of Education Key Laboratory of Earth Exploration and Information Technology,Chengdu University of Technology,Chengdu 610059,China)

机构地区：[1]成都理工大学地球勘探与信息技术教育部重点实验室,四川成都610059

出　　处：《地球科学》2022年第1期15-26,共12页Earth Science

基　　金：中国地质调查局项目(No.DD20160054);国家自然科学基金项目(No.91755215)。

摘　　要：川东北地区三叠系发育巨厚的蒸发岩层,并赋存优质的深层富钾卤水.因构造沉积条件的整体差异,川东北富钾卤水的成因机制与富集规律未有详尽研究.以"气钾兼探"为指导思想,综合利用野外露头-岩心-测井等资料,对川东北地区三叠系蒸发岩分布规律以及岩相古地理演化进行分析,明确了膏盐盆在T_(1)j^(4-5)-T_(2)l^(1)期间规模逐渐缩小、向SW逐渐迁移的分布规律.结合岩心与卤水地球化学分析,判定川东北地区富钾卤水成因机制以海水蒸发浓缩与表层淡水淋滤为主,深部水岩反应较弱.结合井震分析,提出富钾卤水具备"膏盆盐盆控卤、孔隙裂缝储卤、背斜核部富卤"的富集规律.综合认为富钾卤水为"构造-沉积"双重因素控制的"次级深凹"富集模式.During the Triassic period,the Northeast Sichuan developed a huge evaporative salt layer and accumulated high quality deep potassium-rich brine.Due to the overall differences in tectonic depositional conditions,the genetic mechanism and enrichment rules of potassium-rich brine in Northeast Sichuan Basin have not been studied in detail.In this study it takes“gaspotassium exploration”as the guiding ideology,and comprehensively utilizes the field outcrop-core-logging data to analyze the distribution and lithofacies paleogeographic evolution of the Triassic evaporite in the Northeast Sichuan basin,and finally it shows the size of salt basin in Northeast Sichuan decreased gradually and migrated to southwest during T_(1)j^(4-5)-T_(2)l^(1) l1.Combined with core and brine geochemical analysis,it is concluded that the genesis mechanism of potassium-rich brine in Northeast Sichuan is mainly seawater evaporation-concentration mechanism and surface fresh water leaching mechanism,and the deep water-rock reaction is weak.Combined with well logging and seismic interpretation,it is proposed that the potassium-rich brine has the enrichment rule of“controlling brine by the gypsum basin and salt basin;storing brine in the pores and fractures;enriching brine in the core of anticline”.It is considered that the potassium-rich brine is a“secondary deep depression”enrichment model controlled by“structure-deposition”dual factors.

关 键 词：川东北地区 富钾卤水 三叠系 岩相古地理 成钾机制 富集模式 地球化学 

分 类 号：P597[天文地球—地球化学]