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dc.contributor.authorLenton, TM
dc.contributor.authorPogge von Strandmann, PAE
dc.contributor.authorDesrochers, A
dc.contributor.authorMurphy, MJ
dc.contributor.authorFinlay, AJ
dc.contributor.authorSelby, D
dc.date.accessioned2017-06-23T09:28:08Z
dc.date.issued2017-06-15
dc.description.abstractChemical weathering of silicate rocks is a primary drawdown mechanism of atmospheric carbon dioxide. The processes that affect weathering are therefore central in controlling global climate. A temperature-controlled “weathering thermostat” has long been proposed in stabilising long-term climate, but without definitive evidence from the geologic record. 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). We find a positive δ7Li excursion, suggestive of a silicate weathering decline. 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. This lower CO2 drawdown during the glaciation allowed climatic recovery and deglaciation. Combined, the data and model provide support from the geological record for the operation of the weathering thermostat.en_GB
dc.description.sponsorshipThis study and PPvS were funded by NERC advanced research fellowship NE/I020571/2 and ERC Consolidator grant 682760 - CONTROLPASTCO2. AD thanks the support of the Natural Science and Engineering Council of Canada (Discovery Grant). TML was supported by NERC (NE/N018508/1). DS acknowledges the Total Endowment Fund. Michael Melchin is thanked for reading an earlier version of the manuscript. This manuscript was greatly improved by reviews from Lee Kump, Jerome Gaillardet and an anonymous reviewer.en_GB
dc.identifier.citationvol. 3, no. 2en_GB
dc.identifier.doi10.7185/geochemlet.1726
dc.identifier.urihttp://hdl.handle.net/10871/28158
dc.language.isoenen_GB
dc.publisherEuropean Association of Geochemistryen_GB
dc.rightsThis work is distributed under the Creative Commons Attribution 4.0 License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Additional information is available at http://www. geochemicalperspectivesletters.org/copyright-and-permissions.en_GB
dc.titleGlobal climate stabilisation by chemical weathering during the Hirnantian glaciationen_GB
dc.typeArticleen_GB
dc.date.available2017-06-23T09:28:08Z
dc.identifier.issn2224-2759
dc.descriptionArticleen_GB
dc.descriptionThis is the final version of the article. Available from European Association of Geochemistry via the DOI in this record.en_GB
dc.identifier.eissn2410-3403
dc.identifier.journalGeochemical Perspectivesen_GB


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