Sources and Genesis of Subsurface Brine in Sua Pan, Botswana
详细信息
- 责任者：Shan Huimei (State Key Laboratory of Biogeology and Environmental Geology ; China University of Geosciences ; Wuhan 430074 ; China) ; Ma Teng
- 刊名：Earth Science
- 出版年：2013
- 卷期：38(3)
- 关键词：卤水 ; brines ; 盐湖 ; salt lakes ; 博茨瓦纳 ; Botswana
- 页码：p.607-615
- 图表：illus., 5 tables, 25 refs.
- 分类号：1002
- issnNo：ISSN1000-2383
- isbnNo：CN42-1233/P
摘要
The salt lake of Sua Pan,one of the largest salt lakes in Botswana,is important resources of natural alkali.To identify the sources and genesis of subsurface brine in this salt lake,groundwater and surface water near this lake,in addition to subsurface brine water in the lake and salt crystals from solar salt field were collected and determined.The contents of major cation and anion,the isotope compositions of D,18O and 37Cl,and the 14C age of groundwater were calculated.It is found that the subsurface brine is characterized by enriched Na and K,and depleted Ca and Mg.Results of D,18O and 37Cl show that surface water is closely connected with subsurface brine in Sua Pan,while the role of groundwater recharge on it is weak(the difference of 37Cl is 0.04‰-0.06‰).Relationships of TDS-γNa/γCl indicate that leaching of halite affects the formation of this subsurface brine(γNa/γCl≈1),and the age of 14C(about 20 000 years ago)indicates that the fluctuation of ancient climate is considered to be an important factor of the formation of Sua Pan.Based on the above knowledge,inverse simulation of subsurface brine in Sua Pan is modeled by PHREEQC software,which further verifies that salt lake of Sua Pan is mainly the result of strong evaporation and concentration of surface water and halite leaching by groundwater.