CHEN Zhou1，2, WANG Xizhi2*, LI Baosheng1,3, GUAN Gongcou2, LIANG Zhaoxiong2, WANG Jun1,2
(1. School of Geography, South China Normal University, Guangzhou 510631, China;
2. Department of Resource and Environment, Foshan University, Foshan 528000, China;
3. State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi’an 710061, China)
Abstract: The Xingzi river basin is located in typical karst-dominated regions in northwest of Guangdong, and its karstification is better developed, and karst types are better diverse. This basin is the source of upstream of Lianjiang river which is the largest tributary of Beijiang river, and its source of water conditions plays an important role for social and economic development in northwest of Guangdong but especially in the core area of Pearl River Delta. So understanding its water quality conditions and its variation discipline in this basin, is very necessary and has important economic and social significance. Therefore, we collected water samples systematically during summer and winter across the study basin and the samples were analyzed and processed in the laboratory and the field respectively. The result shows that: Ca2+ and HCO3- were the dominant ions, accounted for over70% and 80% of the total cations and anions concentration respectively; Followed by the Mg2+ and SO42-, accounted for about 12% and 8% respectively. Based on the nature of the water, it is divided into soft water and weakly mineralized water. Its main chemical source is dominated by carbonate rock weathering materials and evaporation karst solution materials in this basin and the water chemical type is HCO3-—Ca2+, HCO3-—Ca2+·Mg2+ type, but only a few water samples expressed as HCO3-—Ca2+—SO42- type. And from the Gibbs distribution pattern, we conclude that the major source of hydrochemistry ions is rock weathering, and the dissolution of carbonates may play an important role in controlling the chemical composition of river water, but atmospheric precipitation input and evaporation – concentrated effect had the limited contribution in this area. The temporal variation showed obvious dilution effect of precipitation, and most of the hydrochemical ion component in winter has the higher concentration than in summer. Correlation analysis showed that the spatial variation has the significant features and obvious regularity. This study suggested that carbonate rocks as well as evaporites is the dominance controlling factor of the water chemical and karst geological background has deeply affected the hydro-geochemical types in Xingzi basin.
Key words: Northwest Guangdong; Xingzi basin; rock weathering; hydro-chemical type; spatial and temporal variation; correlation analysis.
EARTH AND ENVIRONMENT Vol. 42, No.2, Tot No.298, 2014, Page 145-156
