We analyzed dissolved major elements, delta C-13(DIC) and delta S-34(SO4) in river waters from a karstic and a granitic terrain to examine weathering processes and the influence of basin geology on water quality and associated riverine alkalinity transport. Results show that waters from the karstic terrain have higher total dissolved solids (TDS), major ion concentrations and delta C-13(DIC) values but lower K+, Na+ and Si concentration and delta S-34(SO4) values than that from the granitic terrain. The compositions of major ions and isotopes indicate that the solute of the granitic terrain are controlled by processes of silicate and carbonate dissolution by carbonic acid. However, carbonate dissolution by both carbonic and sulfuric acid are dominant processes in karstic terrain. Total erosion rates, dissolved inorganic carbon (DIC) flux and CO2 uptake were 28.0 t km(-2) yr(-1), 2.9 x 10(5) mol km(-2) yr(-1) and 2.3 x 10(5) mol km(-2) yr(-1) for the granitic terrain and 70.2 t km(-2) yr(-1), 11.9 x 10(5) mol km(-2) yr(-1) and 6.4 x 10(5) mol km(-2) yr(-1) for the karstic terrain, respectively. These results indicated the karstic area plays an important role in uptake of CO2 and DIC flux along the Yangzte River Basin. Our results also revealed that CO2 uptake due to carbonate chemical weathering in both karstic and granitic terrain is very high and provide as much or more DIC flux than that from silicate chemical weathering. (C) 2012 Elsevier Ltd. All rights reserved.
| Publication name |
JOURNAL OF ASIAN EARTH SCIENCES Volume: 57 Pages: 38-53 Published: SEP 5 2012 |
| Author(s) |
Ji Hongbing; Jiang Yongbin |
| Corresponding author |
JI Hongbing
hongbing_ji@163.com
1. Chinese Acad Sci, Inst Geochem, State Key Lab Environm Geochem, Guiyang 550002, Peoples R China
2. Capital Normal Univ, Coll Resource Environm & Tourism, Beijing 100037, Peoples R China
3. Univ Sci & Technol Beijing, Sch Civil & Environm Engn, Beijing 100083, Peoples R China
4. Anhui Univ Technol, Sch Construct Engn, Dept Environm Engn, Maan Shan 243002, Peoples R China |
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