Sr fluxes and Sr/Sr characterization of river waters from a karstic versus granitic watershed in the Yangtze River |
| |
| Authors: | Yongbin Jiang Hongbing Ji |
| |
| Institution: | 1. State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, 46 Guanshui road, Guiyang 550002, China;2. Department of Environment Engineering, School of Construction Engineering, Anhui University of Technology, 59 Hudong road, Maan Shan 243002, China |
| |
| Abstract: | The watershed in the southern Jiangxi Province (Jiangxi Province is called simply Gan) (SGW) and the watershed in the central Guizhou Province (Guizhou Province is called simply Qian) (CQW) are two subtropical watersheds of the Yangtze River in China. Both watersheds have similar latitudes and climate, but distinct differences in basin lithology. These similarities and differences provide a good natural laboratory in which to investigate weathering processes and Sr end-members in river waters. This work aims to identify and contrast the sources, fluxes and controls on Sr isotopic composition in the river waters of these two areas. Results showed that the 87Sr/86Sr in the SGW waters ranged from 0.716501 to 0.724931, with dissolved Sr averaging 27 μg l− 1. Rhyolites and granites are two major sources for the dissolved Sr. The SGW waters receive 42% of their Sr from silicates weathering, 32% from carbonates and 3.2% from evaporites. 87Sr/86Sr in the CQW waters has a lesser variation from 0.707694 to 0.710039, but higher Sr contents (average of 208 μg l− 1). Dolomite, limestone and dolomitic limestone are major sources of Sr in the waters. The CQW waters receive 69% of their Sr from carbonates, 1.7% from silicates and 0.9% from evaporites. The chemical erosion rate and Sr flux in the CQW are 122 t km− 2 a− 1 and 0.079 t km− 2 a− 1, respectively, which are higher than those of the SGW (56 t km− 2 a− 1 and 0.021 t km− 2 a− 1, respectively). These data suggest that the intensive carbonates weathering occurred in the karstic area in the upper-reach of the Yangtze River exert great influence on the high Sr concentration and low Sr isotopic ratios in the River. |
| |
| Keywords: | Strontium Isotopes Carbonate weathering Silicate weathering |
| 本文献已被 ScienceDirect 等数据库收录！ |
|
