WANG Yushan, CHENXuxue, ZHANG Mengnan

 

(Center for Hydrogeology and Environmental Geology Survey, China Geological Survey,Baoding 071051, China)

 

Abstract: In this study, Gibbs plots and end-member analysis methods were used to identify hydrochemistry, solute sources and chemical weathering processes of Malian river. A forward model of mass budget was established to evaluate the contribution to river water mineralization for halite, sulfate, silicate and carbonate weathering. Results show that river water in this area was brackish with high total dissolved solids and dominated by Na+, Mg2+, Cl- and SO42-. Along flow path, the total dissolved solids of river water decrease and hydrochemical type transfers from Cl-Na upstream to HCO3•SO4-Na•Mg downstream. Water chemistry was mainly controlled by weathering processes, in which evaporite plays a dominant role with average contribution of 76.5%, while silicate and carbonate weathering have contributions of 10.4% and 13.1%, respectively. From upstream to downstream, chemical weathering processes vary spatially and the contribution decreases for halite, while increases for sulfate and carbonate. Lithology condition is the primary factor affecting chemical weathering processes and rainfall and water discharge also highlight significant impacts on water chemistry.

 

Key words: chemical weathering;evaporite; forwardmodel; Malian river basin

 

EARTH AND ENVIRONMENT Vol.46, No.1, Tot No.321, 2018, Page 15-22