Hydrogeochemical and isotopic evidences of the gro

Authors: Chunli Su Yanxin Wang Yulong Pan

Publish Date: 2013/02/01

Volume: 70, Issue: 2, Pages: 877-885

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Abstract

Datong Basin is one of the Cenozoic faulted basins in Northern China’s Shanxi province where groundwater is the major source of water supply The results of hydrochemical investigation show that along the groundwater flow path from the margins to the lowerlying central parts of the basin groundwater generally shows increases in concentrations of TDS HCO3 − SO4 2− Cl− Na+ and Mg2+ except for Ca2+ content Along the basin margin groundwater is dominantly of Ca–HCO3 type however in the central parts of the basin it becomes more saline with Na–HCO3dominant or mixedion type The mediumdeep groundwater has chemical compositions similar to those of shallow groundwater except for the local area affected by human activity From the mountain front to the basin area shallow groundwater concentrations of major ions increase and are commonly higher than those in mediumdeep aquifers due to intense evapotranspiration and anthropogenic contamination Hydrolysis of aluminosilicate and silicate minerals cation exchange and evaporation are prevailing geochemical processes occurring in the aquifers at Datong Basin The isotopic compositions indicate that meteoric water is the main source of groundwater recharge Evaporation is the major way of discharge of shallow groundwater The groundwater in mediumdeep aquifers may be related to regional recharges of rainwater by infiltrating along the mountain front faults and of groundwater permeating laterally from bedrocks of the mountain range However in areas of groundwater depression cones groundwater in the deep confined aquifers may be recharged by groundwater from the upper unconfined aquifer through aquitardsThree anonymous reviewers and the editor are thanked for their great help to improve the quality of the manuscript The research work was jointly supported by National Natural Science Foundation of China Nos 40802058 and 40830748 Ministry of Science and Technology of China 2012AA062602 and the Fundamental Research Fund for National Universities China University of Geosciences Wuhan No CUG120113

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