Murphy 3,ģDepartment of Earth Sciences, University of Oxford, Oxford, OX1 3AN, UK A.J. Desrochers 2,ĢDepartment of Earth and Environmental Sciences, University of Ottawa, ON K1N 6N5, Canada M.J. Combined, the data and model provide support from the geological record for the operation of the weathering thermostat.ġLondon Geochemistry and Isotope Centre, Institute of Earth and Planetary Sciences, University College London and Birkbeck, University of London, Gower Street, London, WC1E 6BT, UK A. This lower CO2 drawdown during the glaciation allowed climatic recovery and deglaciation. Using a coupled lithium-carbon model, we show that initiation of the glaciation was likely caused by declining CO2 degassing, which triggered abrupt global cooling, and much lower weathering rates. We find a positive δ7Li excursion, suggestive of a silicate weathering decline. Here we use lithium isotopes (δ7Li) to assess the impact of silicate weathering across a significant climate-cooling period, the end-Ordovician Hirnantian glaciation (~445 Ma). A temperature-controlled “weathering thermostat” has long been proposed in stabilising long-term climate, but without definitive evidence from the geologic record. The processes that affect weathering are therefore central in controlling global climate. LentonDO - ĪB - Chemical weathering of silicate rocks is a primary drawdown mechanism of atmospheric carbon dioxide. T1 - Global climate stabilisation by chemical weathering during the Hirnantian glaciationĪU - P.A.E.

Iapetus the long road home 2017 review