青藏高原是研究构造隆升-地表风化-气候变化关系的理想场所。以尼洋河流域为研究对象,借助水化学和正演模型,研究硫酸参与的地表风化过程及其对区域CO_2消耗通量和气候变化的影响。结果表明:(1)尼洋河河水的水化学类型主要为HCO_3 · SO_4-Ca · Mg和HCO_3 · SO_4-Ca型,河水阳离子主要来源于碳酸盐和硅酸盐矿物化学风化,分别贡献了河水阳离子总量的79.4%和11.7%;(2)流域内发生了明显的硫化物矿物的化学风化现象,其风化速率(13.5 t · km~(-2) · a~(-1))为流域内硅酸盐矿物风化速率(4.46 t · km~(-2) · a~(-1))的3倍;(3)硫酸参与碳酸盐矿物化学风化引起的CO_2净释放量在很大程度上抵消了流域内碳酸盐和硅酸盐矿物化学风化引起的CO_2消耗通量。
英文摘要:
Tibetan Plateau is an ideal place to study the relationship between tectonic uplift, surface weathering and climate change. Here, the role of sulfuric acid in carbonate and silicate weathering and its effects on the corresponding CO_2 consumption flux and climate change were investigated in Niyang River catchment using hydrochemical method and forward model. The results showed that: (1) The hydrochemical type of Niyang River was characterized by HCO_3 · SO_4-Ca · Mg and HCO_3 · SO_4-Ca. The cations in river water were mainly derived from weathering of carbonate and silicate, contributing to 79.4% and 11.7% of the total water cation, respectively. (2) There was substantial chemical weathering of sulfide minerals in the catchment,with weathering rate (13.5 t · km~(-2) · a~(-1)) being three times as high as that of the silicate mineral weathering (4.46 t · km~(-2) · a~(-1)). (3) The net CO_2 emissions during chemical weathering of carbonate resulted by sulfuric acid, to a large extent, could offset the CO_2 consumption caused by carbonate-silicate mineral weathering in Niyang River catchment.