Global climate stabilisation by chemical weathering during the Hirnantian glaciation
Chemical 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...
| Auteurs principaux: | , , , , , |
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| Format: | Journal article |
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European Association of Geochemistry
2017
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| _version_ | 1826285614582988800 |
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| author | von Strandmann, P Desrochers, A Murphy, M Finlay, A Selby, D Lenton, T |
| author_facet | von Strandmann, P Desrochers, A Murphy, M Finlay, A Selby, D Lenton, T |
| author_sort | von Strandmann, P |
| collection | OXFORD |
| description | Chemical 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. |
| first_indexed | 2024-03-07T01:31:28Z |
| format | Journal article |
| id | oxford-uuid:93c031fb-e00b-4ac5-b3a6-4323e9f75f42 |
| institution | University of Oxford |
| last_indexed | 2024-03-07T01:31:28Z |
| publishDate | 2017 |
| publisher | European Association of Geochemistry |
| record_format | dspace |
| spelling | oxford-uuid:93c031fb-e00b-4ac5-b3a6-4323e9f75f422022-03-26T23:34:28ZGlobal climate stabilisation by chemical weathering during the Hirnantian glaciationJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:93c031fb-e00b-4ac5-b3a6-4323e9f75f42Symplectic Elements at OxfordEuropean Association of Geochemistry2017von Strandmann, PDesrochers, AMurphy, MFinlay, ASelby, DLenton, TChemical 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. |
| spellingShingle | von Strandmann, P Desrochers, A Murphy, M Finlay, A Selby, D Lenton, T Global climate stabilisation by chemical weathering during the Hirnantian glaciation |
| title | Global climate stabilisation by chemical weathering during the Hirnantian glaciation |
| title_full | Global climate stabilisation by chemical weathering during the Hirnantian glaciation |
| title_fullStr | Global climate stabilisation by chemical weathering during the Hirnantian glaciation |
| title_full_unstemmed | Global climate stabilisation by chemical weathering during the Hirnantian glaciation |
| title_short | Global climate stabilisation by chemical weathering during the Hirnantian glaciation |
| title_sort | global climate stabilisation by chemical weathering during the hirnantian glaciation |
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