地学前缘 ›› 2021, Vol. 28 ›› Issue (4): 194-205.DOI: 10.13745/j.esf.sf.2020.6.40

• 水生态、草地生态及污染土壤修复 • 上一篇    下一篇

柴达木盆地大柴旦地区地下水水化学特征及演化规律

张景涛1,2(), 史浙明1,*(), 王广才1, 姜军3, 杨炳超3   

  1. 1.中国地质大学(北京) 地下水循环与环境演化教育部重点实验室, 北京 100083
    2.黄河勘测规划设计研究院有限公司, 河南 郑州 450003
    3.中国地质调查局 西安地质调查中心, 陕西 西安 710054
  • 收稿日期:2020-05-12 修回日期:2020-10-20 出版日期:2021-07-25 发布日期:2021-07-25
  • 通讯作者: 史浙明
  • 作者简介:张景涛(1992—),男,硕士,地质工程专业。E-mail: zhangjt54321@163.com
  • 基金资助:
    国家自然科学基金项目(41672243);“十三五”国家重点研发计划项目(2018YFC1508703);黄河勘测规划设计研究院有限公司自主研发项目(2020-ky02)

Hydrochemical characteristics and evolution of groundwater in the Dachaidan area, Qaidam Basin

ZHANG Jingtao1,2(), SHI Zheming1,*(), WANG Guangcai1, JIANG Jun3, YANG Bingchao3   

  1. 1. Ministry of Education Key Laboratory of Groundwater Circulation and Environmental Evolution, China University of Geosciences (Beijing), Beijing 100083, China
    2. Yellow River Survey, Planning and Design Institute Co., Ltd., Zhengzhou 450003, China
    3. Xi’an Center, China Geological Survey, Xi’an 710054, China
  • Received:2020-05-12 Revised:2020-10-20 Online:2021-07-25 Published:2021-07-25
  • Contact: SHI Zheming

摘要:

地下水在干旱/半干旱地区的生态环境保护中起着主导作用。柴达木盆地北缘的大柴旦湖地处西北干旱区,其生态环境较为脆弱,了解该地区的地下水水化学演化特征,对这一生态敏感地区的地下水可持续利用至关重要。本研究通过采集该地区28 个具有代表性的水样,运用数理统计、Piper图、Gibbs图、离子比值、饱和指数和反向水文地球化学模拟等方法,分析了研究区地下水水化学类型分布特征,探讨了地下水水化学演化过程中的水岩作用。结果表明:(1)由山前冲洪积扇到大柴旦湖,地下水水化学类型由HCO3·Cl·SO4-Na·Ca型向SO4·Cl-Ca·Na、Cl-Na型演化转变,总溶解固体物含量由小于1 g/L增至380 g/L以上。(2)Gibbs图、主要离子比值分析及饱和指数表明,研究区地下水水化学特征主要受水岩作用和蒸发结晶作用控制,沿地下水流路径上,主要发生了岩盐、石膏的溶解,方解石的沉淀,白云石和长石的溶解或沉淀。氯碱指数、[(Na++K+)-Cl-]与[(Ca2++Mg2+)-( HCO 3 -+ SO 4 2 -)]关系表明,阳离子交换作用也影响着该地区地下水水化学组分的形成。(3)通过反向水文地球化学模拟,定量验证了地下水径流过程的主要水-岩作用。

关键词: 地下水, 水化学特征, 演化规律, 大柴旦湖, 柴达木盆地

Abstract:

Groundwater plays an important role in the ecological environmental protection in arid and semi-arid areas. The Dachaidan Lake in the northern margin of the Qaidam Basin is located in the arid, ecologically sensitive northwestern region. For sustainable use of groundwater in this region, it is crucial to understand its hydrochemical evolutionary characteristics. In this study, we collected 28 representative water samples from this area and analyzed the distribution characteristics of groundwater chemical types by using mathematical statistics, Piper chart, Gibbs chart, ion ratio, saturation index and reverse hydrogeochemical simulation; we also discussed the water-rock interaction in the groundwater hydrochemical evolutionary process. The main results are: (1) From the piedmont alluvial fan to the Dachaidan Lake, the hydrochemical type changed from HCO3·Cl·SO4-Na·Ca to SO4·Cl-Ca·Na and Cl-Na while TDS increased from 1 to 380 g/L or more. (2) The gibbs diagram, major ion ratio and saturation index showed the hydrochemical characteristics of groundwater in the study area were mainly controlled by the water-rock interaction and evaporation-crystallization effect, with halite, gypsum and feldspar dissolution and calcite and dolomite deposition along the groundwater flow path. The relationship between chlor-alkali index and [(Na++K+)-Cl-] or [(Ca2++Mg2+)-( HCO 3 -+ SO 4 2 -)] showed the cation exchange also affected the chemical composition of groundwater in the area. (3) Through reverse hydrogeochemical simulation, the main water-rock effect of the groundwater runoff process revealed by qualitative analysis was quantitatively verified.

Key words: groundwater, hydrochemical characteristics, evolution law, Dachaidan Lake, Qaidam Basin

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