Continental chemical weathering flux,chemical denudation rates and net CO₂ consumption rates in the Changjiang drainage basins on the eastern Qinghai-Xizang Plateau

Based on the samples taken from the Changjiang drainage basins on the eastern Qinghai-Xizang Plateau in May and June of 2000,2001 and 2002,the continental chemical weathering flux,chemical denudation rates and net CO₂ consumption rates for individual basins are generalized as follows.(1) The chemical denudation rate is highest(2.34×10⁶ mol/yr/km²) for the Qumar River and lowest(1.40×10⁶ mol/yr/km²) for the Tuotuo River.The chemical denudation rates of the other four main tributaries of the Changjiang River in the region are 1.69×10⁶ mol/yr/km²for the Yalong River,1.74×10⁶ mol/yr/km² for the Jinsha River,1.57×10⁶ mol/yr/km² for the Dadu River,and 1.88×10⁶ mol/yr/km² for the Minjiang River,respectively.(2) The net CO₂ consumption rates in the tributaries of the Yangtze River,on the other hand,are 101.81×10³ mol/yr/km² for the Dadu River,7.55×10³ mol/yr/km²1 for the Qumar River,44.38×10³ mol/yr/km² for the Jinsha River,69.64×10³ mol/yr/km² for the Yalong River,81.90×10³ mol/yr/km² for the Minjiang River,and 21.90×10³ mol/yr/km² for the Tuotuo River,respectively.The physical weathering is considered as a most important factor influencing the chemical denudation rates in the study area.