Tectonic and climatic controls on silicate weathering.

West, A. J. and Galy, A. and Bickle, M. J. (2005) Tectonic and climatic controls on silicate weathering. Earth and Planetary Science Letters, 235 (1-2). pp. 211-228. DOI 10.1016/j.epsl.2005.03.020

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Abstract

Understanding the controls on chemical weathering, especially of silicate minerals, remains a major challenge, despite its importance in controlling the evolution of the Earth's surface. In particular, it has proved hard to distinguish the temperature sensitivity of silicate weathering rates from other factors. Here we present a new compilation of chemical and physical erosion rates in small catchments and show that silicate weathering rates are not governed by any single parameter but require consideration in multiple dimensions. The overall variation in silicate weathering rates with physical erosion rates, rainfall, and temperature can be quantitatively described by a parameterization based on considering their limiting relationships. At lower erosion rates mineral supply limits weathering. At higher erosion rates there is abundant material but kinetic and therefore climatic factors limit weathering. A predictive model describing the field data based on transport and weathering (kinetically) limited scenarios yields theoretically sensible values for fitted parameters. In the transport-limited case, the supply of silicate cations from weathering is directly proportional to the supply of material by erosion, consistent with complete leaching of cations from fresh regolith. In the kinetically limited case, weathering scales directly with runoff, as the square root of erosion rate, and with an activation energy of 74 ± 29 kJ/mol, consistent with expected values in the Earth's surface settings.

Item Type: Article
Uncontrolled Keywords: 2005 AREP 2005 P IA48
Subjects: 01 - Climate Change and Earth-Ocean Atmosphere Systems
Divisions: 01 - Climate Change and Earth-Ocean Atmosphere Systems
Journal or Publication Title: Earth and Planetary Science Letters
Volume: 235
Page Range: pp. 211-228
Identification Number: 10.1016/j.epsl.2005.03.020
Depositing User: Sarah Humbert
Date Deposited: 12 Aug 2010 15:19
Last Modified: 23 Jul 2013 10:00
URI: http://eprints.esc.cam.ac.uk/id/eprint/1876

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