青藏高原东部长江流域盆地地表化学剥蚀通量剥蚀速率大气CO2净消耗率研究

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

关键词:  青藏高原|长江流域|化学剥蚀通量|剥蚀速率|大气CO₂净消耗率

Key words:  Qinghai-Xizang Plateau|Changjiang drainage basin|chemical weathering flux|chemical denudation rate|net CO₂ consumption rate

摘要:

2000~2002年期间,笔者对青藏高原东部长江流域溶质载荷分别进行了取样分析并对流域盆地化学剥蚀通量、剥蚀速率和大气CO₂净消耗率进行了计算。结果表明,流域盆地化学剥蚀速率以河源区楚玛尔河最高为2.34×10⁶mol/a/km²,沱沱河最低为1.40×10⁶mol/a/km²,四大支流雅砻江为1.69×10⁶mol/a/km²,金沙江为1.74×10⁶mol/a/km²,大渡河为1.57×10⁶mol/a/km²,岷江为1.88×10⁶mol/a/km²;流域盆地ФCO₂估算结果以大渡河最高为101.81×10³mol/a/km²,楚玛尔河最低为7.55×10³mol/a/km²,金沙江为44.38×10³mol/a/km²,雅砻江为69.64×10³mol/a/km²,岷江为81.90×10³mol/a/km²,沱沱河为21.90×10³mol/a/km²。并对长江流域地表化学剥蚀速率主要控制因素进行了讨论。

Abstract:

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.