柴达木盆地晚新生代成盐元素时空分布规律

This project is aimed at looking for materials needed urgently for China’s industry, agriculture, and environmental protection. Based on the scientific and technological data accumulated through long-term surveys in Qaidam by our survey team and the advantages of our ownership of the largest quantity of the first-hand data country-wide of drill cores of salt-forming elements in Qaidam, we have many advantages for carrying out a study of salt-forming elements in both the east area and west area and in both the deep part and shallow part in the whole region. Under the guidance of tectono-geochemistry, we will couple the temporal-spatial distribution characteristics of salt-forming elements of Qaidam with regional hyrodchemical and tectono-dynamic mechanism and elucidate the temporal-spatial evolutionary course and accumulation characteristics of major salt-forming elements of the Qaidam Salt Lake; and further make clear the cause of zoning of the hydrochemical types and the sources of lithium, boron, and potash through a combined study of the structural fault transport and storage mechanism and fluid geology and isotope and inclusion tracing so as to realize cooperation and innovation. Finally, an important basis will be provided for developing the theory on “salt formation in continental strata （potash, lithium, boron）” and elucidation of the origins of superlarge lithium and boron deposits.

本项目针对我国工农业和环保急需，基于本团队柴达木长期调查科技积累，以及拥有全国最多的柴达木成盐元素岩芯第一性资料优势，有利于开展全区东、西部、深浅结合的成盐元素研究。项目以盐湖学构造地球化学为指导，将柴达木成盐元素时空分布特点与区域水化学和构造动力学机制相耦合，阐明柴达木盐湖主要成盐元素时空演化历程和聚集规律；通过构造断裂运储机制与流体地质和同位素及包体示踪联合研究，查明水化学类型分带性成因与锂、硼、钾物质来源，实施协同创新。为发展“陆相成盐（钾、锂、硼）”理论和阐明超大型锂、硼成因提供重要依据。

主要研究内容：研究柴达木盆地晚新生代成盐元素时空演化特征，着重开展柴西和“四湖区”调查。部署一里坪、东台吉乃尔湖、西台吉乃尔湖和察尔汗代表性钻孔等；南翼山和黑北凹地深层成盐元素深时演化特征，测定精细年龄及岩石矿物和固液相组成，以及综合对比；柴达木重点控盐断裂构造特征及其对深部流体的控制作用；察尔汗CaCl2 型和南祁连硼锂成盐流体系统示踪研究：开展盆地南北部和环湖水系（盐湖、温泉、湖水）等调查和分析等。.重要结果及科学意义.1..取得可可西里中新世火山-沉积（含大规模热水的白云岩）和柴西大规模深层富锂卤水数据，揭示柴达木两个重要成锂事件：现代锂（硼钾）盐湖沿南北对角线对称分布和沿北西向古近纪-新近纪深层构造带。阐明其成因与印亚陆陆碰撞远程效应密切相关。.2..揭示柴达木盆地巨量石盐迁聚成因模式，由E2-Q4柴达木盐盆及其巨量成盐元素呈“反S”迁移模式，其成因既是印亚陆陆碰撞的远程效应，又与东亚古大气环流相关。晚新生代中亚西风带和冬季风长期滞聚于塔里木-柴西，直至晚更新世，柴东才转化为干冷气候。.3..“陆相成钾理论”的深化和发展；查明柴达木盆地盐湖有多种类型钾盐资源，除了常规晶间卤水外，还查明新构造形成“湖缘成钾”模式和发现新类型砂砾层钾盐卤水和“表外”固体钾盐可大规模工业利用，其资源远景已达世界陆相钾盐最大规模；并厘定砂砾型新的氯化钠亚型卤水。查明柴达木晚新生代钾盐物质是典型陆相来源；通过盆地晚新生代固液相87Sr/86Sr较系统研究，揭示柴达木富钾盐湖具有陆壳物源的特征。.提出青藏高原湖盆是多圈层相互作用和演化的窗口（郑绵平等，2016）是研究青藏深部过程与表生作用的优势区位，在倡议综合集成以往单学科大量成果，揭示多圈层地球动力学演化内在规律，实为当今世界前沿的大科学，对国际多学科发展都有重大意义。