Worldwide distribution of continental rock lithology: Implications for the atmospheric/soil CO_2 uptake by continental weathering and alkalinity river transport to the oceans

摘要

The silicate rock weathering followed by the formation of carbonate rocks in the ocean, transfers CO_2 from the atmosphere to the lithosphere. This CO_2 uptake plays a major role in the regulation of atmospheric CO_2 concentrations at the geologic timescale and is mainly controlled by the chemical properties of rocks. This leads us to develop the first world lithological map with a grid resolution of 1 °× 1 °. This paper analyzes the spatial distribution of the six main rock types by latitude, continents, and ocean drainage basins and for 49 large river basins. Coupling our digital map with the GEM-CO_2 model, we have also calculated the amount of atmospheric/soil CO_2 consumed by rock weathering and alkalinity river transport to the ocean. Among all silicate rocks, shales and basalts appear to have a significant influence on the amount of CO_2 uptake by chemical weathering.