Regional groundwater flow and geochemical evolution in the Amacuzac River Basin, Mexico

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• 作者：Eric Morales-Casique ; Jacobo Guinzberg-Belmont…
• 关键词：Mexico ; Regional groundwater flow ; Hydrogeochemistry ; Principal component analysis ; Geochemical modeling
• 刊名：Hydrogeology Journal
• 出版年：2016
• 出版时间：November 2016
• 年：2016
• 卷：24
• 期：7
• 页码：1873-1890
• 全文大小：3,347 KB
• 刊物类别：Earth and Environmental Science
• 刊物主题：Earth sciences
  Hydrogeology
  Geology
  Waste Water Technology, Water Pollution Control, Water Management and Aquatic Pollution
  
• 出版者：Springer Berlin / Heidelberg
• ISSN：1435-0157
• 卷排序：24

文摘

An approach is presented to investigate the regional evolution of groundwater in the basin of the Amacuzac River in Central Mexico. The approach is based on groundwater flow cross-sectional modeling in combination with major ion chemistry and geochemical modeling, complemented with principal component and cluster analyses. The hydrogeologic units composing the basin, which combine aquifers and aquitards both in granular, fractured and karstic rocks, were represented in sections parallel to the regional groundwater flow. Steady-state cross-section numerical simulations aided in the conceptualization of the groundwater flow system through the basin and permitted estimation of bulk hydraulic conductivity values, recharge rates and residence times. Forty-five water locations (springs, groundwater wells and rivers) were sampled throughout the basin for chemical analysis of major ions. The modeled gravity-driven groundwater flow system satisfactorily reproduced field observations, whereas the main geochemical processes of groundwater in the basin are associated to the order and reactions in which the igneous and sedimentary rocks are encountered along the groundwater flow. Recharge water in the volcanic and volcano-sedimentary aquifers increases the concentration of HCO₃–, Mg2+ and Ca2+ from dissolution of plagioclase and olivine. Deeper groundwater flow encounters carbonate rocks, under closed CO₂ conditions, and dissolves calcite and dolomite. When groundwater encounters gypsum lenses in the shallow Balsas Group or the deeper Huitzuco anhydrite, gypsum dissolution produces proportional increased concentration of Ca2+ and SO₄2–; two samples reflected the influence of hydrothermal fluids and probably halite dissolution. These geochemical trends are consistent with the principal component and cluster analyses.