Taxa de intemperismo químico e consumo de CO2 em relevo cuestiforme com substrato basáltico e arenítico no estado de São Paulo, Brasil

This paper quantified the chemical weathering rate and CO 2 consumption in basaltic and sandstone cuesta landscape based on sodium, potassium, calcium, magnesium, and silica elements using the Jau River, in the state of Sao Paulo, Brazil, as the study area. The mobility of SiO 2 , Na + , K + , Ca 2+ and Mg 2+ elements in the rock/soil system occurs in the alteration stages of potassium feldspar, albite, anorthite, augite, and anorthoclase primary minerals. The rainwater data indicate an annual deposition of 1.28 t/km -2 /year for SiO 2 , 0.60 t/km -2 /year for Ca 2+ , 0.43 t/km -2 /year for Mg 2+ , 0.34 t/km -2 /year for K + and 0.27 t/km -2 /year for Na + . In the river waters, the annual specific flow was calculated as 7.11 t/km -2 /year for SiO 2 , 4.72 t/km -2 /year for Ca 2+ , 2.33 t/km -2 /year for Na + , 2.44 t/km -2 /year for Mg 2+ and 0.88 t/km -2 /year for K + . The atmospheric/soil CO 2 consumption was 0.57x10 6 mol.km -2 /year for the Jau River basin and when it was extrapolated to the Basaltic Cuestas geomorphological province in Sao Paulo State, it was estimated as 0.03x10 12 mol/year, which is an important consideration to global warming. The chemical weathering rate (10 m/Ma) was compared with other studies in different geomorphological provinces in Sao Paulo State, which has a variation between 6 and 22 m/Ma.