Silicate weathering rate and its controlling factors: A study from small granitic watersheds in the Jiuhua Mountains

摘要

Silicate weathering is intimately linked to global climate. To investigate the controlling factors of silicate weathering rate, we collected monthly or half-monthly river water samples from ten small granitic watersheds in the Jiuhua Mountains. Mass balance calculation shows that agricultural activity, atmospheric input, silicate weathering, carbonate weathering and evaporite dissolution contribute 2.0%, 16.9%, 58.7%, 13.5% and 8.9% cations to the river water, respectively. The disproportionate contribution of carbonate rocks with an exposed area of < 5% demonstrates the importance of trace carbonate minerals in these small granitic watersheds. The average silicate weathering and CO2 consumption rates at our sites are 7.0 t km(-2) y(-1) and 3.4 x 10(5) mol km(-2) y(-1), respectively.