| Abstract: | Climatic effects on chemical weathering are evaluated by correlating variations in solute concentrations and fluxes with temperature, precipitation, runoff, and evapotranspiration (ET) for a worldwide distribution of sixty-eight watersheds underlain by granitoid rock types. Stream solute concentrations are strongly correlated with proportional ET loss, and evaporative concentration makes stream solute concentrations an inapprorpiate surrogate for chemical weathering. Chemical fluxes are unaffected by ET, and SiO2 and Na weathering fluxes exhibit systematic increases with precipitation, runoff, and temperature. However, warm and wet watersheds produce anomalously rapid weathering rates. A proposed model that provides an improved prediction of weathering rates over climatic extremes is the product of linear precipitation and Arrhenius temperature functions. The resulting apparent activation energies based on SiO2 and Na fluxes are 59.4 and 62.5 kJ.mol-1, respectively. The coupling between temperature and precipitation emphasizes the importance of tropical regions in global silicate weathering fluxes, and suggests it is not representative to use continental averages for temperature and precipitation in the weathering rate functions of global carbon cycling and climatic change models. Fluxes of K, Ca, and Mg exhibit no climatic correlation, implying that other processes, such as ion exchange, nutrient cycling, and variations in lithology, obscure any climatic signal. -from Authors |
| Genre: | Article |
| ProdID: | 70019112 |
| Citation Author: | White, A. F.; Blum, A. E. |
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| Citation End Page: | 1747 |
| Citation Issue: | 9 |
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| Citation Language: | English |
| Citation Larger Work Title: | Geochimica et Cosmochimica Acta |
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| Citation Number Of Pages: | 19 |
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| Citation Search Results Text: | Effects of climate on chemical weathering in watersheds; 1995; Article; Journal; Geochimica et Cosmochimica Acta; White, A. F.; Blum, A. E. |
| Citation Start Page: | 1729 |
| Citation Volume: | 59 |
| Citation Year: | 1995 |
| Type: | citation/reference |
| Text: | Effects of climate on chemical weathering in watersheds; 1995; Article; Journal; Geochimica et Cosmochimica Acta; White, A. F.; Blum, A. E. |
| URL (THUMBNAIL): | http://pubs.er.usgs.gov/thumbnails/outside_thumb.jpg |
| Date Other: | Sun, 1 Jan 1995 00:00 -0600 |
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