Covariance of Microfossil Assemblages and Microbialite Textures Across an Upper Mesoproterozoic Carbonate Platform
Early diagenetic chert nodules and beds in the upper Mesoproterozoic Angmaat (formerly Society Cliffs) Formation, Baffin and Bylot islands, preserve microfossils and primary petrofabrics that record microbial mat deposition and lithification across a range of peritidal carbonate environments. Five d...
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ftharvardudash:oai:dash.harvard.edu:1/12336339 2023-05-15T15:35:28+02:00 Covariance of Microfossil Assemblages and Microbialite Textures Across an Upper Mesoproterozoic Carbonate Platform Knoll, Andrew Herbert Wörndle, Sarah Kah, Linda C. 2013 application/pdf http://nrs.harvard.edu/urn-3:HUL.InstRepos:12336339 https://doi.org/10.2110/palo.2013.p13-005r en_US eng Society for Sedimentary Geology doi:10.2110/palo.2013.p13-005r PALAIOS Knoll, Andrew H., Sarah Wörndle, and Linda C. Kah. 2013. Covariance of Microfossil Assemblages and Microbialite Textures Across an Upper Mesoproterozoic Carbonate Platform. PALAIOS 28, no. 7: 453–470. 0883-1351 http://nrs.harvard.edu/urn-3:HUL.InstRepos:12336339 cyanobacteria petrofabric Baffin Island Bylot Supergroup taphonomy Journal Article 2013 ftharvardudash https://doi.org/10.2110/palo.2013.p13-005r 2022-04-04T20:50:55Z Early diagenetic chert nodules and beds in the upper Mesoproterozoic Angmaat (formerly Society Cliffs) Formation, Baffin and Bylot islands, preserve microfossils and primary petrofabrics that record microbial mat deposition and lithification across a range of peritidal carbonate environments. Five distinct microfossil assemblages document the distribution of mat-building and mat-dwelling populations across a gradient from restricted, frequently exposed flats to more persistently subaqueous environments. Mats built primarily by thin filamentous or coccoidal cyanobacteria give way to a series of more robust forms that show increasing assemblage diversity with decreasing evidence of subaerial exposure. Distinct fabric elements are associated with each microbial assemblage, and aspects of these petrofabrics are recognizably preserved within unsilicified carbonate in the same beds. These include some features that are distinctly geologic in nature (e.g., seafloor cements) and others that reflect microbial growth and decomposition (e.g., tufted microbialites). A particularly distinctive, micronodular fabric is here interpreted as carbonate infilling of primary voids within microbial mat structures. Such structures mark the co-occurrence of cyanobacterial photosynthesis that produced oxygen gas, filamentous mat builders that imparted the coherence necessary to trap gas bubbles, elevated carbonate saturation required to preserve void fabrics via penecontemporaneous cementation, and a relative paucity of detrital sediment that would have inhibited mat growth. Petrofabrics preserved in Angmaat samples are widespread in upper Paleoproterozoic and Mesoproterozoic carbonate successions but are rare thereafter, perhaps recording, at least in part, the declining carbonate saturation state of seawater. Covariation of microfossil assemblages with petrofabrics in both silicified and unsilicified portions of carbonate beds supports hypotheses that link stromatolite microstructure to the composition and diversity of mat communities. Earth and Planetary Sciences Organismic and Evolutionary Biology Accepted Manuscript Article in Journal/Newspaper Baffin Island Baffin Harvard University: DASH - Digital Access to Scholarship at Harvard Baffin Island PALAIOS 28 7 453 470 |
institution |
Open Polar |
collection |
Harvard University: DASH - Digital Access to Scholarship at Harvard |
op_collection_id |
ftharvardudash |
language |
English |
topic |
cyanobacteria petrofabric Baffin Island Bylot Supergroup taphonomy |
spellingShingle |
cyanobacteria petrofabric Baffin Island Bylot Supergroup taphonomy Knoll, Andrew Herbert Wörndle, Sarah Kah, Linda C. Covariance of Microfossil Assemblages and Microbialite Textures Across an Upper Mesoproterozoic Carbonate Platform |
topic_facet |
cyanobacteria petrofabric Baffin Island Bylot Supergroup taphonomy |
description |
Early diagenetic chert nodules and beds in the upper Mesoproterozoic Angmaat (formerly Society Cliffs) Formation, Baffin and Bylot islands, preserve microfossils and primary petrofabrics that record microbial mat deposition and lithification across a range of peritidal carbonate environments. Five distinct microfossil assemblages document the distribution of mat-building and mat-dwelling populations across a gradient from restricted, frequently exposed flats to more persistently subaqueous environments. Mats built primarily by thin filamentous or coccoidal cyanobacteria give way to a series of more robust forms that show increasing assemblage diversity with decreasing evidence of subaerial exposure. Distinct fabric elements are associated with each microbial assemblage, and aspects of these petrofabrics are recognizably preserved within unsilicified carbonate in the same beds. These include some features that are distinctly geologic in nature (e.g., seafloor cements) and others that reflect microbial growth and decomposition (e.g., tufted microbialites). A particularly distinctive, micronodular fabric is here interpreted as carbonate infilling of primary voids within microbial mat structures. Such structures mark the co-occurrence of cyanobacterial photosynthesis that produced oxygen gas, filamentous mat builders that imparted the coherence necessary to trap gas bubbles, elevated carbonate saturation required to preserve void fabrics via penecontemporaneous cementation, and a relative paucity of detrital sediment that would have inhibited mat growth. Petrofabrics preserved in Angmaat samples are widespread in upper Paleoproterozoic and Mesoproterozoic carbonate successions but are rare thereafter, perhaps recording, at least in part, the declining carbonate saturation state of seawater. Covariation of microfossil assemblages with petrofabrics in both silicified and unsilicified portions of carbonate beds supports hypotheses that link stromatolite microstructure to the composition and diversity of mat communities. Earth and Planetary Sciences Organismic and Evolutionary Biology Accepted Manuscript |
format |
Article in Journal/Newspaper |
author |
Knoll, Andrew Herbert Wörndle, Sarah Kah, Linda C. |
author_facet |
Knoll, Andrew Herbert Wörndle, Sarah Kah, Linda C. |
author_sort |
Knoll, Andrew Herbert |
title |
Covariance of Microfossil Assemblages and Microbialite Textures Across an Upper Mesoproterozoic Carbonate Platform |
title_short |
Covariance of Microfossil Assemblages and Microbialite Textures Across an Upper Mesoproterozoic Carbonate Platform |
title_full |
Covariance of Microfossil Assemblages and Microbialite Textures Across an Upper Mesoproterozoic Carbonate Platform |
title_fullStr |
Covariance of Microfossil Assemblages and Microbialite Textures Across an Upper Mesoproterozoic Carbonate Platform |
title_full_unstemmed |
Covariance of Microfossil Assemblages and Microbialite Textures Across an Upper Mesoproterozoic Carbonate Platform |
title_sort |
covariance of microfossil assemblages and microbialite textures across an upper mesoproterozoic carbonate platform |
publisher |
Society for Sedimentary Geology |
publishDate |
2013 |
url |
http://nrs.harvard.edu/urn-3:HUL.InstRepos:12336339 https://doi.org/10.2110/palo.2013.p13-005r |
geographic |
Baffin Island |
geographic_facet |
Baffin Island |
genre |
Baffin Island Baffin |
genre_facet |
Baffin Island Baffin |
op_relation |
doi:10.2110/palo.2013.p13-005r PALAIOS Knoll, Andrew H., Sarah Wörndle, and Linda C. Kah. 2013. Covariance of Microfossil Assemblages and Microbialite Textures Across an Upper Mesoproterozoic Carbonate Platform. PALAIOS 28, no. 7: 453–470. 0883-1351 http://nrs.harvard.edu/urn-3:HUL.InstRepos:12336339 |
op_doi |
https://doi.org/10.2110/palo.2013.p13-005r |
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PALAIOS |
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28 |
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7 |
container_start_page |
453 |
op_container_end_page |
470 |
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1766365797689589760 |