Modelagem do controle climático nas taxas de erosão mecânica e de intemperismo químico na bacia do Rio Sorocaba (SP)

Alexandre Martins Fernandes, Fabiano Tomazini da Conceição, Eder Paulo Spatti Junior, Antonio Aparecido Couto Junior, Jefferson Mortatti

Abstract


The influence of climate control on soil removal and chemical weathering rates in the Sorocaba River Basin, SP, was evaluated through the physicochemical characterization of the fluvial waters and the quantification of TSS and TDS concentrations and fluvial fluxes at two sampling points (S1 and S2) from June 2009 to June 2010. Based on the discharge variation over the study period, 12 scenarios were established with the respective concentrations of TSS, TDS, SiO2 and dissolved cations. After correction of the atmospheric and anthropogenic inputs, were determined the rates of soil removal (WM) and chemical weathering of the rocks (WCh) in the Sorocaba River Basin, i.e., 49.5 and 9.6 m/Ma at S1 and 12.8 and 7.6 m/Ma at S2, respectively. The balance between these rates showed a higher soil removal in S1 (WM ≈ 5.2 WCh) compared to S2 (WM ≈ 1,7 WCh). Evaluated through the RE index, the chemical weathering indicated a tendency to towards the monosialitization domain. The proposed scenarios corroborated the climate influence, with predominance of chemical weathering of the rocks processes under low rainfall and milder temperatures, and the predominance of soil removal processes in warm and rainy climatic conditions.


Keywords


Natural systems modeling; Fluvial geochemistry; Watershed; Anthropogenic influences.



DOI: http://dx.doi.org/10.21715/GB2358-2812.2019331050

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