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A model for evaluating continental chemical weathering from riverine transports of dissolved major elements at a global scale

Lechuga-Crespo, Juan-Luis and Sanchez-Pérez, José Miguel and Simeoni-Sauvage, Sabine and Hartmann, Jens and Amiotte-Suchet, Philippe and Probst, Jean-Luc and Ruiz-Romera, Estilita A model for evaluating continental chemical weathering from riverine transports of dissolved major elements at a global scale. (2020) Global and Planetary Change, 192. 1-14. ISSN 0921-8181

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Official URL: https://doi.org/10.1016/j.gloplacha.2020.103226

Abstract

This study presents a process-based-empirical model for the assessment of ionic fluxes derived from chemical weathering of rocks (ICWR) at a global scale. The equations are designed and the parameters fitted using riverine transport of dissolved major ions Ca2+, Mg2+, K+, Na+, Cl−, SO42−, and alkalinity at a global scale by combining point sampling analysis with spatial descriptions of hydrology, climate, topography, lithology and soil variables such as mineral composition and regolith thickness. Different configurations of the model are considered and the results show that the previously reported “soil shielding” effect on chemical weathering (CW) of rocks presents different values for each of the ions considered. Overall, there is good agreement between median and ranges in observed and simulated data, but further analysis is required to downscale the model to catchment scale. Application to the global scale provides the first global ICWR map, resulting in an average cationic flux derived from chemical weathering of 734·106 Mg·y−1, where 58% is Ca2+, 15% is Mg2+, 24% is Na+ and 3% is K+, and an average anionic flux derived from chemical weathering of 2640·106 Mg·y−1, where 74% is alkalinity, 18% is SO42−, and 8% is Cl−. Hyperactive and hotspot areas are elucidated and compared between ions.

Item Type:Article
HAL Id:hal-02896415
Audience (journal):International peer-reviewed journal
Uncontrolled Keywords:
Institution:French research institutions > Centre National de la Recherche Scientifique - CNRS (FRANCE)
Université de Toulouse > Institut National Polytechnique de Toulouse - Toulouse INP (FRANCE)
Université de Toulouse > Université Toulouse III - Paul Sabatier - UT3 (FRANCE)
Other partners > Universität Hamburg (GERMANY)
Other partners > Université Bourgogne Franche-Comté - UBFC (FRANCE)
Other partners > University of the Basque Country - UPV/EHU (SPAIN)
Laboratory name:
Funders:
Basque Government (Consolidated Group IT 1029–16) - University of the Basque Country (UPV/EHU) (UFI 11/26) - Toulouse INP - Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) under Germany's Excellence Strategy – EXC 2037 ‘Climate, Climatic Change, and Society’ – Project Number: 390683824
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Deposited On:10 Jul 2020 12:59

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