Modern Closed-Basin Potash Evaporites and Brine Evolution, Qaidam Basin, Qinghai Province, China

古钾镁矾的来源，从母岩的角度来看， 沃茨、沉积环境和形成时间是 争议主要是因为没有现代含钾盆地 已经被详细描述。 本研究的目的是 记录地球化学和沉积学条件 中国西部柴达木盆地的钾盐成矿作用， 现代层状钾盐（光卤石和钾盐）广泛存在于 开发 该项目包括三个相互关联的部分： (1)流入沃茨的化学性质及其向盐水的演变， 使用计算机化的特定离子相互作用溶液模型，（2） 现代钾盐矿床的野外和岩相学研究， 伴生卤水地球化学;（3）全新世-更新世 卤水演化历史与钾盐沉积研究 两个岩心（岩盐中的流体包裹体，孔隙流体化学， 和岩石学）。 许多古老的钾盐矿床缺乏MgSO 4-盐， 具有海水蒸发岩序列的特征。 哈迪（1984年， 在审查）挑战了古代MgSO 4的海洋起源无 提出了一种新的水热成因模式 流入沃茨，特别是那些形成于构造- 活跃盆地 柴达木盆地现代构造研究 活动，无MgSO 4钾长石，和主要的春季流入， 将允许测试新的假设， 碳酸钾

The origin of ancient potash evaporites, in terms of parent waters, depositional environments, and timing of formation is controversial largely because no modern potash-bearing basins have been described in detail. The goal of this study is to document the geochemical and sedimentological conditions of potash mineralization in the Qaidam Basin of western China, where modern bedded potash salts (carnallite and sylvite) are widely developed. The project consists of three interrelated parts: (1) chemistry of inflow waters and their evolution into brines, using a computerized specific ion interaction solution model, (2) field and petrographic study of modern potash salt deposits and geochemistry of associated brines, and (3) Holocene-Pleistocene history of brine evolution and potash salt deposition from study of two cores (fluid inclusions in halite, pore fluid chemistry, and petrography). Many ancient potash deposits lack the MgSO4-salts that are characteristic of a seawater evaporite sequence. Hardie (1984, in review) challenged the marine origin of ancient MgSO4-free potash evaporites and proposed a new model involving hydrothermal inflow waters, especially for those formed in tectonically- active basins. Study of the Qaidam Basin, with recent tectonic activity, MgSO4-free potash evaporites, and major spring inflow, will allow testing of new hypotheses on the origins of ancient potash evaporites.