Water geochemistry of the Xijiang basin rivers, South China: Chemical weathering and CO2 consumption | |
Zhifang Xu;Cong-Qiang Liu | |
2010 | |
Source Publication | Applied Geochemistry
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Volume | 25Issue:10Pages:1603-1614 |
Abstract | The Xijiang River, the mainstream of the Zhujiang (Pearl) River, which is the second largest river in China in terms of discharge, flows through a large carbonate rock region in South China. The chemical and Sr isotopic compositions of the Xijiang waters were determined during the high-flow season in order to understand the chemical weathering processes, associated CO2 consumption and anthropogenic influences within the carbonate-dominated basin. The major ion compositions of the river waters are characterized by the dominance of Ca2+, Mg2+, HCO3- and are significantly rich in SO42-. The SO42- is mainly derived from the oxidation of sulfide minerals and acid precipitation caused by coal combustion. Chemical and Sr isotopic compositions of the river waters indicate that four reservoirs (carbonates, silicates, evaporites and anthropogenic inputs) contribute to the total dissolved loads. The chemical weathering rates of carbonates and silicates for the Xijiang basin are estimated to be approximately 78.5 and 7.45 ton km−2 a−1, respectively. The total chemical weathering rate of rocks for the Xijiang basin is approximately 86.1 ton km−2 a−1 or 42 mm ka−1, which is much higher than global mean values. The budgets of CO2 consumption by carbonate and silicate weathering are estimated to be 284 × 109 and 54.3 × 109 mol a−1, respectively. It would appear that H2SO4 is involved as a proton donor in weathering reactions in the Xijiang basin; calculated results show that the contribution of cations from rock weathering induced by H2SO4 accounts for approximately 11.2%. Results from this study show that the flux of CO2 released into the atmosphere is approximately 0.1 × 106 mol C km−2 a−1 or 0.41 × 1012 g C a−1 produced by H2SO4-induced carbonate weathering in the basin. When extrapolated to the entire surface area of carbonate in SW China, the flux of CO2 released to the atmosphere by H2SO4-induced carbonate weathering is about 1.41 × 1012 g C a−1. |
Indexed By | SCI |
Language | 英语 |
Document Type | 期刊论文 |
Identifier | http://ir.gyig.ac.cn/handle/42920512-1/9500 |
Collection | 环境地球化学国家重点实验室 |
Affiliation | 1.Key Laboratory of Engineering Geomechanics, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China 2.State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, Guizhou 550002, China |
Recommended Citation GB/T 7714 | Zhifang Xu;Cong-Qiang Liu. Water geochemistry of the Xijiang basin rivers, South China: Chemical weathering and CO2 consumption[J]. Applied Geochemistry,2010,25(10):1603-1614. |
APA | Zhifang Xu;Cong-Qiang Liu.(2010).Water geochemistry of the Xijiang basin rivers, South China: Chemical weathering and CO2 consumption.Applied Geochemistry,25(10),1603-1614. |
MLA | Zhifang Xu;Cong-Qiang Liu."Water geochemistry of the Xijiang basin rivers, South China: Chemical weathering and CO2 consumption".Applied Geochemistry 25.10(2010):1603-1614. |
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