Snowball Earth climate dynamics and Cryogenian geology-geobiology

Geological evidence indicates that grounded ice sheets reached sea level at all latitudes during two long-lived Cryogenian (58 and ≥5 My) glaciations. Combined uranium-lead and rhenium-osmium dating suggests that the older (Sturtian) glacial onset and both terminations were globally synchronous. Geo...

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Published in:Science Advances
Main Authors: Hoffman, Paul F, Abbot, Dorian S, Ashkenazy, Yosef, Benn, Douglas I., Brocks, Jochen, Cohen, Phoebe A, Cox, Grant M, Creveling, Jessica R, Donnadieu, Yannick, Erwin, Douglas H, Fairchild, I.J.
Format: Article in Journal/Newspaper
Language:English
Published: American Association for the Advancement of Science
Subjects:
Online Access:http://hdl.handle.net/1885/160756
https://doi.org/10.1126/sciadv.1600983
https://openresearch-repository.anu.edu.au/bitstream/1885/160756/5/01_Hoffman_Snowball_Earth_climate_2017.pdf.jpg
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spelling ftanucanberra:oai:openresearch-repository.anu.edu.au:1885/160756 2024-01-14T10:07:44+01:00 Snowball Earth climate dynamics and Cryogenian geology-geobiology Hoffman, Paul F Abbot, Dorian S Ashkenazy, Yosef Benn, Douglas I. Brocks, Jochen Cohen, Phoebe A Cox, Grant M Creveling, Jessica R Donnadieu, Yannick Erwin, Douglas H Fairchild, I.J. application/pdf http://hdl.handle.net/1885/160756 https://doi.org/10.1126/sciadv.1600983 https://openresearch-repository.anu.edu.au/bitstream/1885/160756/5/01_Hoffman_Snowball_Earth_climate_2017.pdf.jpg en_AU eng American Association for the Advancement of Science 2375-2548 http://hdl.handle.net/1885/160756 doi:10.1126/sciadv.1600983 https://openresearch-repository.anu.edu.au/bitstream/1885/160756/5/01_Hoffman_Snowball_Earth_climate_2017.pdf.jpg © 2017 The Authors Science Advances Journal article ftanucanberra https://doi.org/10.1126/sciadv.1600983 2023-12-15T09:32:57Z Geological evidence indicates that grounded ice sheets reached sea level at all latitudes during two long-lived Cryogenian (58 and ≥5 My) glaciations. Combined uranium-lead and rhenium-osmium dating suggests that the older (Sturtian) glacial onset and both terminations were globally synchronous. Geochemical data imply that CO2 was 102 PAL (present atmospheric level) at the younger termination, consistent with a global ice cover. Sturtian glaciation followed breakup of a tropical supercontinent, and its onset coincided with the equatorial emplacement of a large igneous province. Modeling shows that the small thermal inertia of a globally frozen surface reverses the annual mean tropical atmospheric circulation, producing an equatorial desert and net snow and frost accumulation elsewhere. Oceanic ice thickens, forming a sea glacier that flows gravitationally toward the equator, sustained by the hydrologic cycle and by basal freezing and melting. Tropical ice sheets flow faster as CO2 rises but lose mass and become sensitive to orbital changes. Equatorial dust accumulation engenders supraglacial oligotrophic meltwater ecosystems, favorable for cyanobacteria and certain eukaryotes. Meltwater flushing through cracks enables organic burial and submarine deposition of airborne volcanic ash. The subglacial ocean is turbulent and well mixed, in response to geothermal heating and heat loss through the ice cover, increasing with latitude. Terminal carbonate deposits, unique to Cryogenian glaciations, are products of intense weathering and ocean stratification. Whole-ocean warming and collapsing peripheral bulges allow marine coastal flooding to continue long after ice-sheet disappearance. The evolutionary legacy of Snowball Earth is perceptible in fossils and living organisms. Article in Journal/Newspaper Ice Sheet Australian National University: ANU Digital Collections Science Advances 3 11 e1600983
institution Open Polar
collection Australian National University: ANU Digital Collections
op_collection_id ftanucanberra
language English
description Geological evidence indicates that grounded ice sheets reached sea level at all latitudes during two long-lived Cryogenian (58 and ≥5 My) glaciations. Combined uranium-lead and rhenium-osmium dating suggests that the older (Sturtian) glacial onset and both terminations were globally synchronous. Geochemical data imply that CO2 was 102 PAL (present atmospheric level) at the younger termination, consistent with a global ice cover. Sturtian glaciation followed breakup of a tropical supercontinent, and its onset coincided with the equatorial emplacement of a large igneous province. Modeling shows that the small thermal inertia of a globally frozen surface reverses the annual mean tropical atmospheric circulation, producing an equatorial desert and net snow and frost accumulation elsewhere. Oceanic ice thickens, forming a sea glacier that flows gravitationally toward the equator, sustained by the hydrologic cycle and by basal freezing and melting. Tropical ice sheets flow faster as CO2 rises but lose mass and become sensitive to orbital changes. Equatorial dust accumulation engenders supraglacial oligotrophic meltwater ecosystems, favorable for cyanobacteria and certain eukaryotes. Meltwater flushing through cracks enables organic burial and submarine deposition of airborne volcanic ash. The subglacial ocean is turbulent and well mixed, in response to geothermal heating and heat loss through the ice cover, increasing with latitude. Terminal carbonate deposits, unique to Cryogenian glaciations, are products of intense weathering and ocean stratification. Whole-ocean warming and collapsing peripheral bulges allow marine coastal flooding to continue long after ice-sheet disappearance. The evolutionary legacy of Snowball Earth is perceptible in fossils and living organisms.
format Article in Journal/Newspaper
author Hoffman, Paul F
Abbot, Dorian S
Ashkenazy, Yosef
Benn, Douglas I.
Brocks, Jochen
Cohen, Phoebe A
Cox, Grant M
Creveling, Jessica R
Donnadieu, Yannick
Erwin, Douglas H
Fairchild, I.J.
spellingShingle Hoffman, Paul F
Abbot, Dorian S
Ashkenazy, Yosef
Benn, Douglas I.
Brocks, Jochen
Cohen, Phoebe A
Cox, Grant M
Creveling, Jessica R
Donnadieu, Yannick
Erwin, Douglas H
Fairchild, I.J.
Snowball Earth climate dynamics and Cryogenian geology-geobiology
author_facet Hoffman, Paul F
Abbot, Dorian S
Ashkenazy, Yosef
Benn, Douglas I.
Brocks, Jochen
Cohen, Phoebe A
Cox, Grant M
Creveling, Jessica R
Donnadieu, Yannick
Erwin, Douglas H
Fairchild, I.J.
author_sort Hoffman, Paul F
title Snowball Earth climate dynamics and Cryogenian geology-geobiology
title_short Snowball Earth climate dynamics and Cryogenian geology-geobiology
title_full Snowball Earth climate dynamics and Cryogenian geology-geobiology
title_fullStr Snowball Earth climate dynamics and Cryogenian geology-geobiology
title_full_unstemmed Snowball Earth climate dynamics and Cryogenian geology-geobiology
title_sort snowball earth climate dynamics and cryogenian geology-geobiology
publisher American Association for the Advancement of Science
url http://hdl.handle.net/1885/160756
https://doi.org/10.1126/sciadv.1600983
https://openresearch-repository.anu.edu.au/bitstream/1885/160756/5/01_Hoffman_Snowball_Earth_climate_2017.pdf.jpg
genre Ice Sheet
genre_facet Ice Sheet
op_source Science Advances
op_relation 2375-2548
http://hdl.handle.net/1885/160756
doi:10.1126/sciadv.1600983
https://openresearch-repository.anu.edu.au/bitstream/1885/160756/5/01_Hoffman_Snowball_Earth_climate_2017.pdf.jpg
op_rights © 2017 The Authors
op_doi https://doi.org/10.1126/sciadv.1600983
container_title Science Advances
container_volume 3
container_issue 11
container_start_page e1600983
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