Origin of Underground Brine in Potassium-Bearing Strata in Khammouane, Central Laos

doi:10.1134/S0016702919120139

ISL OpenIR > 盐湖地质与环境实验室

	Origin of Underground Brine in Potassium-Bearing Strata in Khammouane, Central Laos
	Qin, Zhanjie; Li, Qingkuan; Fan, Qishun; Zhang, Xiangru; Du, Yongsheng; Wei, Haicheng; Yuan, Qin; Wang, Jianping; Shan, Fashou
	2019-10
发表期刊	GEOCHEMISTRY INTERNATIONAL
ISSN	0016-7029
卷号	57 期号:12 页码:1327-1338
摘要	The Khorat Plateau is one of the largest potash deposits in the world. In recent years, exploitation of potash resources accompanied by leakage of underground brines (UB) in potassium-bearing strata has threatened mining safety. However, there is little research on origin of UB in Laos. In this study, twelve samples of UB, salt springs (SS) and river waters were collected in Khammouane mining area, central Laos and analyzed for ionic and boron isotopic compositions. The results show that both of UB, dominated by K+, Mg2+, Na+ and Cl- ions, and SS, enriched in Na+ and Cl-, are chloride-type brines, while river waters abundant in Ca2+ and HC ions are carbonate-type waters. K+ (35.1-53.7 g/L) and Rb+ (12.9-16.6 mg/L) concentrations of UB are higher than the peak (25.9 g/L, 9.4 mg/L) of seawater evaporation trajectories (SET). UB is also characterized by high Mg2+ (32.7-68.0 g/L) and Br- (1795.2-2801.3 mg/L) concentrations and its lg(Cl/Br) ratios (1.9-2.1) deviate from the halite dissolution line. These comparisons indicate that the water chemistries of UB are mainly influenced by dissolution of carnallite and sylvite. High Sr2+ concentrations (31.8-58.6 mg/L) in UB might be simultaneously associated with dissolution of potash salt and Ca-bearing minerals (carbonate and anhydrite). The negative saturation indices (SI) of different salt minerals in UB suggest that salt minerals are unsaturated in UB. Meanwhile, boron (B) concentrations (396.0-426.0 mg/L) and delta B-11 values (+19.8-+21.0%) of UB fall in between low B-delta B-11 end member (0.02 mg/L, +2.31%) of river water and high B-delta B-11 end member (126.7-890.8 mu g/g, +25.94-+32.94%) of evaporitic minerals. The comparison implies that UB was influenced and mixed by two end members. Therefore, combining with major and trace ionic concentrations, isotopic compositions and lithologies of salt-bearing strata revealed by drillings in mining area, we conclude that the major solute source in UB is derived from dissolution of carnallite and sylvite. These geochemical evidences provide insights into dealing with leakage of underground brines occurred in the underground mining of potash deposits in Laos.
DOI	10.1134/S0016702919120139
引用统计
文献类型	期刊论文
条目标识符	http://ir.isl.ac.cn/handle/363002/34042
专题	盐湖地质与环境实验室中国科学院青海盐湖研究所盐湖资源与化学实验室
推荐引用方式 GB/T 7714	Qin, Zhanjie,Li, Qingkuan,Fan, Qishun,et al. Origin of Underground Brine in Potassium-Bearing Strata in Khammouane, Central Laos[J]. GEOCHEMISTRY INTERNATIONAL,2019,57(12):1327-1338.
APA	Qin, Zhanjie.,Li, Qingkuan.,Fan, Qishun.,Zhang, Xiangru.,Du, Yongsheng.,...&Shan, Fashou.(2019).Origin of Underground Brine in Potassium-Bearing Strata in Khammouane, Central Laos.GEOCHEMISTRY INTERNATIONAL,57(12),1327-1338.
MLA	Qin, Zhanjie,et al."Origin of Underground Brine in Potassium-Bearing Strata in Khammouane, Central Laos".GEOCHEMISTRY INTERNATIONAL 57.12(2019):1327-1338.

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