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Large equatorial seasonal cycle during Marinoan snowball Earth

In the equatorial regions on Earth today, the seasonal cycle of the monthly mean surface air temperature is <10°C. However, deep (>1 m) sand wedges were found near the paleoequator in the Marinoan glaciogenic deposits at ~635 million years ago, indicating a large seasonal cycle (probably >3...

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Autores principales: Liu, Yonggang, Yang, Jun, Bao, Huiming, Shen, Bing, Hu, Yongyun
Formato: Online Artículo Texto
Lenguaje:English
Publicado: American Association for the Advancement of Science 2020
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7269644/
https://www.ncbi.nlm.nih.gov/pubmed/32537489
http://dx.doi.org/10.1126/sciadv.aay2471
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author Liu, Yonggang
Yang, Jun
Bao, Huiming
Shen, Bing
Hu, Yongyun
author_facet Liu, Yonggang
Yang, Jun
Bao, Huiming
Shen, Bing
Hu, Yongyun
author_sort Liu, Yonggang
collection PubMed
description In the equatorial regions on Earth today, the seasonal cycle of the monthly mean surface air temperature is <10°C. However, deep (>1 m) sand wedges were found near the paleoequator in the Marinoan glaciogenic deposits at ~635 million years ago, indicating a large seasonal cycle (probably >30°C). Through numerical simulations, we show that the equatorial seasonal cycle could reach >30°C at various continental locations if the oceans are completely frozen over, as would have been the case for a snowball Earth, or could reach ~20°C if the oceans are not completely frozen over, as would have been the case for a waterbelt Earth. These values are obtained at the maximum eccentricity of the Earth orbit, i.e., 0.0679, and will be approximately 10°C smaller if the present-day eccentricity is used. For these seasonal cycles, theoretical calculations show that the deep sand wedges form readily in a snowball Earth while hardly form in a waterbelt Earth.
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spelling pubmed-72696442020-06-11 Large equatorial seasonal cycle during Marinoan snowball Earth Liu, Yonggang Yang, Jun Bao, Huiming Shen, Bing Hu, Yongyun Sci Adv Research Articles In the equatorial regions on Earth today, the seasonal cycle of the monthly mean surface air temperature is <10°C. However, deep (>1 m) sand wedges were found near the paleoequator in the Marinoan glaciogenic deposits at ~635 million years ago, indicating a large seasonal cycle (probably >30°C). Through numerical simulations, we show that the equatorial seasonal cycle could reach >30°C at various continental locations if the oceans are completely frozen over, as would have been the case for a snowball Earth, or could reach ~20°C if the oceans are not completely frozen over, as would have been the case for a waterbelt Earth. These values are obtained at the maximum eccentricity of the Earth orbit, i.e., 0.0679, and will be approximately 10°C smaller if the present-day eccentricity is used. For these seasonal cycles, theoretical calculations show that the deep sand wedges form readily in a snowball Earth while hardly form in a waterbelt Earth. American Association for the Advancement of Science 2020-06-03 /pmc/articles/PMC7269644/ /pubmed/32537489 http://dx.doi.org/10.1126/sciadv.aay2471 Text en Copyright © 2020 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works. Distributed under a Creative Commons Attribution NonCommercial License 4.0 (CC BY-NC). http://creativecommons.org/licenses/by-nc/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution-NonCommercial license (http://creativecommons.org/licenses/by-nc/4.0/) , which permits use, distribution, and reproduction in any medium, so long as the resultant use is not for commercial advantage and provided the original work is properly cited.
spellingShingle Research Articles
Liu, Yonggang
Yang, Jun
Bao, Huiming
Shen, Bing
Hu, Yongyun
Large equatorial seasonal cycle during Marinoan snowball Earth
title Large equatorial seasonal cycle during Marinoan snowball Earth
title_full Large equatorial seasonal cycle during Marinoan snowball Earth
title_fullStr Large equatorial seasonal cycle during Marinoan snowball Earth
title_full_unstemmed Large equatorial seasonal cycle during Marinoan snowball Earth
title_short Large equatorial seasonal cycle during Marinoan snowball Earth
title_sort large equatorial seasonal cycle during marinoan snowball earth
topic Research Articles
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7269644/
https://www.ncbi.nlm.nih.gov/pubmed/32537489
http://dx.doi.org/10.1126/sciadv.aay2471
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