Dodging snowballs:geochronology of the Gaskiers glaciation and the first appearance of the Ediacaran biota
The snowball Earth hypothesis predicts that low-latitude glaciation lasted millions of years while CO 2 built up to critical levels to culminate in catastrophic deglaciation in a supergreenhouse climate. The Gaskiers Formation of eastern Newfoundland (Canada) has been attributed to a snowball glacia...
Published in: | Geology |
---|---|
Main Authors: | , , , , , , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
2016
|
Subjects: | |
Online Access: | https://research-portal.st-andrews.ac.uk/en/publications/1fd381bd-f285-4ee0-9d7d-5c024defcbca https://doi.org/10.1130/G38284.1 |
id |
ftunstandrewcris:oai:research-portal.st-andrews.ac.uk:publications/1fd381bd-f285-4ee0-9d7d-5c024defcbca |
---|---|
record_format |
openpolar |
spelling |
ftunstandrewcris:oai:research-portal.st-andrews.ac.uk:publications/1fd381bd-f285-4ee0-9d7d-5c024defcbca 2024-10-13T14:09:09+00:00 Dodging snowballs:geochronology of the Gaskiers glaciation and the first appearance of the Ediacaran biota Pu, Judy P. Bowring, Samuel A. Ramezani, Jahandar Myrow, Paul Raub, Timothy D. Landing, Ed Mills, Andrea Hodgin, Eben Macdonald, Francis A. 2016-11-01 https://research-portal.st-andrews.ac.uk/en/publications/1fd381bd-f285-4ee0-9d7d-5c024defcbca https://doi.org/10.1130/G38284.1 eng eng info:eu-repo/semantics/restrictedAccess Pu , J P , Bowring , S A , Ramezani , J , Myrow , P , Raub , T D , Landing , E , Mills , A , Hodgin , E & Macdonald , F A 2016 , ' Dodging snowballs : geochronology of the Gaskiers glaciation and the first appearance of the Ediacaran biota ' , Geology , vol. 44 , no. 11 , pp. 955-958 . https://doi.org/10.1130/G38284.1 article 2016 ftunstandrewcris https://doi.org/10.1130/G38284.1 2024-10-02T23:40:45Z The snowball Earth hypothesis predicts that low-latitude glaciation lasted millions of years while CO 2 built up to critical levels to culminate in catastrophic deglaciation in a supergreenhouse climate. The Gaskiers Formation of eastern Newfoundland (Canada) has been attributed to a snowball glaciation event, but the lack of robust paleomagnetic data and precise geochronological constraints has precluded tests of the hypothesis. Here we present high-precision U-Pb zircon geochronology (chemical abrasion-isotope dilution-thermal ionization mass spectrometry) from eight tuffs from multiple distant stratigraphic sections that bracket glacial diamictites and the first appearance of large Ediacaran fossils. Including internal error, deposition of the Gaskiers diamictite on the Avalon Peninsula is constrained to have been between 580.90 ± 0.40 and 579.88 ± 0.44 Ma, and the Trinity diamictite on Bonavista Peninsula was deposited between 579.63 ± 0.15 and 579.24 ± 0.17 Ma. Assuming approximately synchronous deglaciation, these results imply a maximum duration for deposition of the Trinity diamictite of ≤340 k.y.; this is inconsistent with the multimillion year duration predicted by the snowball Earth hypothesis. Our geochronologic data also constrain the first appearance datum of Ediacaran fossils to < 9.5 m.y. after the Gaskiers glaciation. Thus, despite existing paleomagnetic constraints that indicate that marine ice sheets extended to low to middle latitudes, it appears that Earth narrowly escaped a third Neoproterozoic snowball glaciation just prior to the late Ediacaran expansion of metazoan ecosystems. Article in Journal/Newspaper Newfoundland University of St Andrews: Research Portal Canada Geology 44 11 955 958 |
institution |
Open Polar |
collection |
University of St Andrews: Research Portal |
op_collection_id |
ftunstandrewcris |
language |
English |
description |
The snowball Earth hypothesis predicts that low-latitude glaciation lasted millions of years while CO 2 built up to critical levels to culminate in catastrophic deglaciation in a supergreenhouse climate. The Gaskiers Formation of eastern Newfoundland (Canada) has been attributed to a snowball glaciation event, but the lack of robust paleomagnetic data and precise geochronological constraints has precluded tests of the hypothesis. Here we present high-precision U-Pb zircon geochronology (chemical abrasion-isotope dilution-thermal ionization mass spectrometry) from eight tuffs from multiple distant stratigraphic sections that bracket glacial diamictites and the first appearance of large Ediacaran fossils. Including internal error, deposition of the Gaskiers diamictite on the Avalon Peninsula is constrained to have been between 580.90 ± 0.40 and 579.88 ± 0.44 Ma, and the Trinity diamictite on Bonavista Peninsula was deposited between 579.63 ± 0.15 and 579.24 ± 0.17 Ma. Assuming approximately synchronous deglaciation, these results imply a maximum duration for deposition of the Trinity diamictite of ≤340 k.y.; this is inconsistent with the multimillion year duration predicted by the snowball Earth hypothesis. Our geochronologic data also constrain the first appearance datum of Ediacaran fossils to < 9.5 m.y. after the Gaskiers glaciation. Thus, despite existing paleomagnetic constraints that indicate that marine ice sheets extended to low to middle latitudes, it appears that Earth narrowly escaped a third Neoproterozoic snowball glaciation just prior to the late Ediacaran expansion of metazoan ecosystems. |
format |
Article in Journal/Newspaper |
author |
Pu, Judy P. Bowring, Samuel A. Ramezani, Jahandar Myrow, Paul Raub, Timothy D. Landing, Ed Mills, Andrea Hodgin, Eben Macdonald, Francis A. |
spellingShingle |
Pu, Judy P. Bowring, Samuel A. Ramezani, Jahandar Myrow, Paul Raub, Timothy D. Landing, Ed Mills, Andrea Hodgin, Eben Macdonald, Francis A. Dodging snowballs:geochronology of the Gaskiers glaciation and the first appearance of the Ediacaran biota |
author_facet |
Pu, Judy P. Bowring, Samuel A. Ramezani, Jahandar Myrow, Paul Raub, Timothy D. Landing, Ed Mills, Andrea Hodgin, Eben Macdonald, Francis A. |
author_sort |
Pu, Judy P. |
title |
Dodging snowballs:geochronology of the Gaskiers glaciation and the first appearance of the Ediacaran biota |
title_short |
Dodging snowballs:geochronology of the Gaskiers glaciation and the first appearance of the Ediacaran biota |
title_full |
Dodging snowballs:geochronology of the Gaskiers glaciation and the first appearance of the Ediacaran biota |
title_fullStr |
Dodging snowballs:geochronology of the Gaskiers glaciation and the first appearance of the Ediacaran biota |
title_full_unstemmed |
Dodging snowballs:geochronology of the Gaskiers glaciation and the first appearance of the Ediacaran biota |
title_sort |
dodging snowballs:geochronology of the gaskiers glaciation and the first appearance of the ediacaran biota |
publishDate |
2016 |
url |
https://research-portal.st-andrews.ac.uk/en/publications/1fd381bd-f285-4ee0-9d7d-5c024defcbca https://doi.org/10.1130/G38284.1 |
geographic |
Canada |
geographic_facet |
Canada |
genre |
Newfoundland |
genre_facet |
Newfoundland |
op_source |
Pu , J P , Bowring , S A , Ramezani , J , Myrow , P , Raub , T D , Landing , E , Mills , A , Hodgin , E & Macdonald , F A 2016 , ' Dodging snowballs : geochronology of the Gaskiers glaciation and the first appearance of the Ediacaran biota ' , Geology , vol. 44 , no. 11 , pp. 955-958 . https://doi.org/10.1130/G38284.1 |
op_rights |
info:eu-repo/semantics/restrictedAccess |
op_doi |
https://doi.org/10.1130/G38284.1 |
container_title |
Geology |
container_volume |
44 |
container_issue |
11 |
container_start_page |
955 |
op_container_end_page |
958 |
_version_ |
1812815999291883520 |