Salt Crystallization Sequences of Nonmarine Brine and Their Application for the Formation of Potassium Deposits
Salt Crystallization Sequences of Nonmarine Brine and Their Application for the Formation of Potassium Deposits
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海相卤水的盐结晶序列及其在钾矿床形成中的应用
DOI：
10.1007/s10498-018-9340-3
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发表时间：
2018
影响因子：
1.6
通讯作者：
Luo Yangbing
中科院分区：
文献类型：
--
作者：
Ye Chuanyong;Mao Jianye;Ren Yaqiong;Li Yingping;Lin Yongjie;Power Ian M;Luo Yangbing
为了更好地认识柴达木盆地钾矿的形成，对尕斯库勒盐湖（GSL）浓缩卤水蒸发过程中沉淀的盐组合进行了研究。该研究包括实验室中25 °C的等温蒸发和GSL油田池塘中的太阳能蒸发。盐水密度增加，成为中等酸性（pH值为5.30），而主要离子地球化学和沉淀物矿物学都表现出两个系统之间的广泛协议。在等温蒸发实验中，鉴定出4种盐组合：石盐→石盐+六水石膏→石盐+水氯镁石+光卤石→水氯镁石。在太阳蒸发过程中，可识别出3种盐组合：石盐→石盐+泻盐+光卤石→石盐+光卤石+水氯镁石。两个系统之间盐组合的关键差异归因于相对湿度和温度条件的差异。虽然GSL有深泉入流补给，但高丰度的MgSO4盐表明盐组合与正常海水蒸发相似。因此，不同比例的深泉水和河水既可以形成缺镁钾蒸发岩，也可以形成正常海水钾镁矾。因此，在地质构造、水文地质和气候条件适宜的陆相盆地中，非海相水可形成多种类型的钾蒸发岩矿床。
The salt assemblages precipitated during evaporation of concentrated brine collected from Gasikule Salt Lake (GSL) were studied to better understand the formation of potassium deposits in the Qaidam Basin. The study included isothermal evaporation at 25 °C in the laboratory and solar evaporation in the ponds at GSL field. Brines increased in density and became moderately acidic (pH ≈ 5.30) while major ion geochemistry and precipitate mineralogy all showed broad agreement between both systems. Four salt assemblages were identified in the isothermal evaporation experiment: halite → halite + hexahydrite → halite + bischofite + carnallite → bischofite. Alternately, three salt assemblages were recognized in the solar evaporation: halite → halite + epsomite + carnallite → halite + carnallite + bischofite. The key difference in salt assemblages between the two systems is attributed to differences in relative humidity and temperature conditions. Although the GSL has deep spring inflow recharge, the high abundance of MgSO4salts demonstrates that the salt assemblages are similar to normal seawater evaporation. Thus, different proportions of deep spring inflow and river water could form both MgSO4-deficient potassium evaporite and normal seawater potassium evaporites. Therefore, nonmarine water may form diverse potassium evaporite deposits in continental basins when the geological structure as well as hydrogeological and climatic conditions is appropriate.