Email this article Origin of Underground Brine in Potassium-Bearing Strata in Khammouane, Central Laos
- Authors: Zhanjie Qin 1,2,3, Li Q.1,2,3, Fan Q.1,2, Zhang X.1,2,3, Du Y.1,2,3, Wei H.1,2, Yuan Q.1,2,3, Wang J.1,2, Shan F.1,2
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Affiliations:
- Key Laboratory of Comprehensive and Highly Efficient Utilization of Salt Lake Resources, Qinghai Institute of Salt Lakes, Chinese Academy of Sciences
- Qinghai Provincial Key Laboratory of Geology and Environment of Salt Lakes
- University of Chinese Academy of Sciences
- Issue: Vol 57, No 12 (2019)
- Pages: 1327-1338
- Section: Article
- URL: https://bakhtiniada.ru/0016-7029/article/view/156397
- DOI: https://doi.org/10.1134/S0016702919120139
- ID: 156397
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Abstract
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\({\text{O}}_{3}^{ - }\) 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 δ11B values (+19.8–+21.0‰) of UB fall in between low B–δ11B end member (0.02 mg/L, +2.31‰) of river water and high B-δ11B end member (126.7–890.8 μg/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.
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About the authors
Zhanjie Qin
Key Laboratory of Comprehensive and Highly Efficient Utilization of Salt Lake Resources, Qinghai Institute of Salt Lakes, Chinese Academy of Sciences; Qinghai Provincial Key Laboratory of Geology and Environment of Salt Lakes; University of Chinese Academy of Sciences
Author for correspondence.
Email: qinzhanjie@isl.ac.cn
China, Xining, 810008; Xining, 810008; Beijing, 100049
Qingkuan Li
Key Laboratory of Comprehensive and Highly Efficient Utilization of Salt Lake Resources, Qinghai Institute of Salt Lakes, Chinese Academy of Sciences; Qinghai Provincial Key Laboratory of Geology and Environment of Salt Lakes; University of Chinese Academy of Sciences
Email: jianpingwang@isl.ac.cn
China, Xining, 810008; Xining, 810008; Beijing, 100049
Qishun Fan
Key Laboratory of Comprehensive and Highly Efficient Utilization of Salt Lake Resources, Qinghai Institute of Salt Lakes, Chinese Academy of Sciences; Qinghai Provincial Key Laboratory of Geology and Environment of Salt Lakes
Email: jianpingwang@isl.ac.cn
China, Xining, 810008; Xining, 810008
Xiangru Zhang
Key Laboratory of Comprehensive and Highly Efficient Utilization of Salt Lake Resources, Qinghai Institute of Salt Lakes, Chinese Academy of Sciences; Qinghai Provincial Key Laboratory of Geology and Environment of Salt Lakes; University of Chinese Academy of Sciences
Email: jianpingwang@isl.ac.cn
China, Xining, 810008; Xining, 810008; Beijing, 100049
Yongsheng Du
Key Laboratory of Comprehensive and Highly Efficient Utilization of Salt Lake Resources, Qinghai Institute of Salt Lakes, Chinese Academy of Sciences; Qinghai Provincial Key Laboratory of Geology and Environment of Salt Lakes; University of Chinese Academy of Sciences
Email: jianpingwang@isl.ac.cn
China, Xining, 810008; Xining, 810008; Beijing, 100049
Haicheng Wei
Key Laboratory of Comprehensive and Highly Efficient Utilization of Salt Lake Resources, Qinghai Institute of Salt Lakes, Chinese Academy of Sciences; Qinghai Provincial Key Laboratory of Geology and Environment of Salt Lakes
Email: jianpingwang@isl.ac.cn
China, Xining, 810008; Xining, 810008
Qin Yuan
Key Laboratory of Comprehensive and Highly Efficient Utilization of Salt Lake Resources, Qinghai Institute of Salt Lakes, Chinese Academy of Sciences; Qinghai Provincial Key Laboratory of Geology and Environment of Salt Lakes; University of Chinese Academy of Sciences
Email: jianpingwang@isl.ac.cn
China, Xining, 810008; Xining, 810008; Beijing, 100049
Jianping Wang
Key Laboratory of Comprehensive and Highly Efficient Utilization of Salt Lake Resources, Qinghai Institute of Salt Lakes, Chinese Academy of Sciences; Qinghai Provincial Key Laboratory of Geology and Environment of Salt Lakes
Author for correspondence.
Email: jianpingwang@isl.ac.cn
China, Xining, 810008; Xining, 810008
Fashou Shan
Key Laboratory of Comprehensive and Highly Efficient Utilization of Salt Lake Resources, Qinghai Institute of Salt Lakes, Chinese Academy of Sciences; Qinghai Provincial Key Laboratory of Geology and Environment of Salt Lakes
Email: jianpingwang@isl.ac.cn
China, Xining, 810008; Xining, 810008
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