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- Creator:
- Howard, Cecilia M. and Sheldon, Nathan D.
- Description:
- This study uses a compilation of microbialite occurrences in the Archean and Paleoproterozoic from the literature to investigate how depositional environment changed across environmental shifts such as the Great Oxidation Event and the Huronian Glaciations. Key Points: - We compiled microbialite occurrences from the Archean and Paleoproterozoic with broad depositional environment information, which has not previously been incorporated in larger compilations of occurrences. - Tidal and other terrestrially-influenced settings comprise the majority of the early microbialite record, even across major environmental shifts and Abstract: Changes in microbialite abundance during the Archean and Paleoproterozoic have been attributed to a variety of environmental and biological factors. Past work looking at large-scale patterns of microbialite abundance generally assumes shallow marine deposition rather than incorporating specific settings, however, there is significant variance in conditions that might impact microbialite formation and preservation between marine, tidal, and terrestrial environments. We compiled microbialite occurrences from the Archean and Paleoproterozoic with integrated depositional environment information in order to assess how microbialite development and preservation changed across different settings. Microbially induced sedimentary structures formed a significant part of the record, but their identification primarily in conjunction with stromatolites rather than independently suggests that they may be undercounted. Broad trends in abundance were similar to previous compilations, but critically, we found that the majority of microbialites from this period formed in tidal environments. The proportion of terrestrially-influenced (including tidal) microbialites increased during periods of craton development in the Neoarchean and mid-Paleoproterozoic, with increases in marine microbialite abundance trailing. Tidal microbialite abundance also recovered more quickly than marine abundance following the Great Oxidation Event and Huronian Glaciations.
- Keyword:
- Microbialite, Stromatolite, Archean, Paleoproterozoic, Geosciences, and Tidal
- Citation to related publication:
- Howard, C.M. and Sheldon, N.D. (in prep). Chapter 2 Microbialite Niches across the Archean and Paleoproterozoic.
- Discipline:
- Science
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- Creator:
- Hinz, Isaac and Johnson, Jena
- Description:
- Laboratory experiments were conducted to compare iron precipitation under completely ferruginous conditions with solutions that contain a low amount of oxidized iron, which can be seen as a proxy for iron oxidation in the environment. and Some XRD files are from a copper source (Cu_XRD) and others are from a cobalt source (Co_XRD).
- Keyword:
- Iron silicates, Greenalite, and Archean
- Citation to related publication:
- Isaac L. Hinz, Christine Nims, Samantha Theuer, Alexis S. Templeton, Jena E. Johnson; Ferric iron triggers greenalite formation in simulated Archean seawater. Geology 2021; doi: https://doi.org/10.1130/G48495.1
- Discipline:
- Science