Did an asteroid impact cause temporary warming during snowball Earth?
Did an asteroid impact cause temporary warming during snowball Earth?
The ca. 717 Ma low-latitude Sturtian “snowball Earth” glaciation lasted ∼56 Myr. However, sedimentological evidence for transient, open ocean conditions during the glaciation appears to contradict the concept of a global deep freeze. We demonstrate multiple lines of geologic evidence from five continents for a temporary, localized sea-ice retreat during the middle of the Sturtian glaciation, which coincides with one, perhaps two, asteroid impacts, and arguably more terrestrial impacts as inferred from the lunar impact record. The well-dated Jänisjärvi impact (ca. 687 Ma) is synchronous with repeated volcanic ash falls whose deposition is most parsimoniously interpreted to indicate a partially ice-free ocean. Temporary greenhouse warming caused by the vaporization of sea ice can explain localized glacial retreat within restricted seaways between these continents, where ice flow would have been constricted and sea ice thinnest before impact.
Lan, Zhongwu
4526d3e1-2a26-4136-a047-4d8a9394763f
Mitchell, Ross
4697e046-5853-4611-8143-b64b65923a97
Gernon, Thomas
658041a0-fdd1-4516-85f4-98895a39235e
Nordsvan, Adam
d50a2594-a913-467f-88ce-16af0a131b61
Lan, Zhongwu
4526d3e1-2a26-4136-a047-4d8a9394763f
Mitchell, Ross
4697e046-5853-4611-8143-b64b65923a97
Gernon, Thomas
658041a0-fdd1-4516-85f4-98895a39235e
Nordsvan, Adam
d50a2594-a913-467f-88ce-16af0a131b61
Lan, Zhongwu, Mitchell, Ross, Gernon, Thomas and Nordsvan, Adam
(2022)
Did an asteroid impact cause temporary warming during snowball Earth?
Earth and Planetary Science Letters, 581.
(doi:10.1016/j.epsl.2022.117407).
Abstract
The ca. 717 Ma low-latitude Sturtian “snowball Earth” glaciation lasted ∼56 Myr. However, sedimentological evidence for transient, open ocean conditions during the glaciation appears to contradict the concept of a global deep freeze. We demonstrate multiple lines of geologic evidence from five continents for a temporary, localized sea-ice retreat during the middle of the Sturtian glaciation, which coincides with one, perhaps two, asteroid impacts, and arguably more terrestrial impacts as inferred from the lunar impact record. The well-dated Jänisjärvi impact (ca. 687 Ma) is synchronous with repeated volcanic ash falls whose deposition is most parsimoniously interpreted to indicate a partially ice-free ocean. Temporary greenhouse warming caused by the vaporization of sea ice can explain localized glacial retreat within restricted seaways between these continents, where ice flow would have been constricted and sea ice thinnest before impact.
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Accepted/In Press date: 29 January 2022
e-pub ahead of print date: 11 February 2022
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Local EPrints ID: 454684
URI: http://eprints.soton.ac.uk/id/eprint/454684
ISSN: 0012-821X
PURE UUID: b2821aad-5c90-4344-b32e-89de26f19e12
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Date deposited: 21 Feb 2022 17:34
Last modified: 22 Feb 2022 02:39
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Author:
Zhongwu Lan
Author:
Ross Mitchell
Author:
Adam Nordsvan
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