Contributions to the Neoproterozoic Geobiology
This thesis makes several contributions to improve our understanding of the Neoproterozoic Paleobiology. In chapter 1, a comprehensive quantitative analysis of the Ediacara fossils indicates that the oldest Ediacara assemblage "the Avalon assemblage" already encompassed the full range of E...
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Virginia Tech
2007
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ftvirginiatec:oai:vtechworks.lib.vt.edu:10919/29979 2024-05-19T07:49:53+00:00 Contributions to the Neoproterozoic Geobiology Shen, Bing Geosciences Xiao, Shuhai Bodnar, Robert J. Read, James Fredrick Kowalewski, Michal 2007-11-29 application/pdf http://hdl.handle.net/10919/29979 http://scholar.lib.vt.edu/theses/available/etd-12072007-104326/ unknown Virginia Tech Revised_BingShen_January7_New.pdf etd-12072007-104326 http://hdl.handle.net/10919/29979 http://scholar.lib.vt.edu/theses/available/etd-12072007-104326/ In Copyright http://rightsstatements.org/vocab/InC/1.0/ Neoproterozoic Ediacaran Ediacara fossils China Carbon isotope Sulfur isotope Disparity Dissertation 2007 ftvirginiatec 2024-05-01T00:44:07Z This thesis makes several contributions to improve our understanding of the Neoproterozoic Paleobiology. In chapter 1, a comprehensive quantitative analysis of the Ediacara fossils indicates that the oldest Ediacara assemblage "the Avalon assemblage" already encompassed the full range of Ediacara morphospace. A comparable morphospace range was occupied by the subsequent White Sea and Nama assemblages, although it was populated differently. In contrast, taxonomic richness increased in the White Sea assemblage and declined in the Nama assemblage. The Avalon morphospace expansion mirrors the Cambrian explosion, and both may reflect similar underlying mechanisms. Chapter 2 describes problematic macrofossils collected from the Neoproterozoic slate of the upper Zhengmuguan Formation in North China and sandstone of the Zhoujieshan Formation in Chaidam. Some of these fossils were previously interpreted as animal traces. Our study of these fossils recognizes four genera and five species. None of these taxa can be interpreted as animal traces. Instead, they are problematic body fossils of unresolved phylogenetic affinities. Chapter 3 reports stable isotopes of the Zhamoketi cap dolostone atop the Tereeken diamictite in the Quruqtagh area, eastern Chinese Tianshan. Our new data indicate that carbonate associated sulfate (CAS) abundance decreases rapidly in the basal cap dolostone and 34SCAS composition varies between +9â ° and +15â ° in the lower 2.5 m. In the overlying interval, CAS abundance remains low while 34SCAS rises ~5â ° and varies more widely between +10â ° and +21â °. 34Spy is typically greater than 34SCAS measured from the same samples. We propose that CAS and pyrite were derived from two isotopically distinct reservoirs in a chemically stratified basin. Chapter 4 studies 13C, 18O, 34SCAS, and 34Spy of the Zhoujieshan cap carbonate that overlies the Ediacaran Hongtiegou glaciation. The Zhoujieshan cap dolostone shows positive 13C values (0 â 1.7â °). 34SCAS shows rapid stratigraphic variations from +13.9 to ... Doctoral or Postdoctoral Thesis White Sea VTechWorks (VirginiaTech) |
institution |
Open Polar |
collection |
VTechWorks (VirginiaTech) |
op_collection_id |
ftvirginiatec |
language |
unknown |
topic |
Neoproterozoic Ediacaran Ediacara fossils China Carbon isotope Sulfur isotope Disparity |
spellingShingle |
Neoproterozoic Ediacaran Ediacara fossils China Carbon isotope Sulfur isotope Disparity Shen, Bing Contributions to the Neoproterozoic Geobiology |
topic_facet |
Neoproterozoic Ediacaran Ediacara fossils China Carbon isotope Sulfur isotope Disparity |
description |
This thesis makes several contributions to improve our understanding of the Neoproterozoic Paleobiology. In chapter 1, a comprehensive quantitative analysis of the Ediacara fossils indicates that the oldest Ediacara assemblage "the Avalon assemblage" already encompassed the full range of Ediacara morphospace. A comparable morphospace range was occupied by the subsequent White Sea and Nama assemblages, although it was populated differently. In contrast, taxonomic richness increased in the White Sea assemblage and declined in the Nama assemblage. The Avalon morphospace expansion mirrors the Cambrian explosion, and both may reflect similar underlying mechanisms. Chapter 2 describes problematic macrofossils collected from the Neoproterozoic slate of the upper Zhengmuguan Formation in North China and sandstone of the Zhoujieshan Formation in Chaidam. Some of these fossils were previously interpreted as animal traces. Our study of these fossils recognizes four genera and five species. None of these taxa can be interpreted as animal traces. Instead, they are problematic body fossils of unresolved phylogenetic affinities. Chapter 3 reports stable isotopes of the Zhamoketi cap dolostone atop the Tereeken diamictite in the Quruqtagh area, eastern Chinese Tianshan. Our new data indicate that carbonate associated sulfate (CAS) abundance decreases rapidly in the basal cap dolostone and 34SCAS composition varies between +9â ° and +15â ° in the lower 2.5 m. In the overlying interval, CAS abundance remains low while 34SCAS rises ~5â ° and varies more widely between +10â ° and +21â °. 34Spy is typically greater than 34SCAS measured from the same samples. We propose that CAS and pyrite were derived from two isotopically distinct reservoirs in a chemically stratified basin. Chapter 4 studies 13C, 18O, 34SCAS, and 34Spy of the Zhoujieshan cap carbonate that overlies the Ediacaran Hongtiegou glaciation. The Zhoujieshan cap dolostone shows positive 13C values (0 â 1.7â °). 34SCAS shows rapid stratigraphic variations from +13.9 to ... |
author2 |
Geosciences Xiao, Shuhai Bodnar, Robert J. Read, James Fredrick Kowalewski, Michal |
format |
Doctoral or Postdoctoral Thesis |
author |
Shen, Bing |
author_facet |
Shen, Bing |
author_sort |
Shen, Bing |
title |
Contributions to the Neoproterozoic Geobiology |
title_short |
Contributions to the Neoproterozoic Geobiology |
title_full |
Contributions to the Neoproterozoic Geobiology |
title_fullStr |
Contributions to the Neoproterozoic Geobiology |
title_full_unstemmed |
Contributions to the Neoproterozoic Geobiology |
title_sort |
contributions to the neoproterozoic geobiology |
publisher |
Virginia Tech |
publishDate |
2007 |
url |
http://hdl.handle.net/10919/29979 http://scholar.lib.vt.edu/theses/available/etd-12072007-104326/ |
genre |
White Sea |
genre_facet |
White Sea |
op_relation |
Revised_BingShen_January7_New.pdf etd-12072007-104326 http://hdl.handle.net/10919/29979 http://scholar.lib.vt.edu/theses/available/etd-12072007-104326/ |
op_rights |
In Copyright http://rightsstatements.org/vocab/InC/1.0/ |
_version_ |
1799468457098477568 |