Work Description

Date: 31 March, 2025

Dataset Title: Microbialite Occurrence Data for the Archean and Paleoproterozoic

Dataset Contact: Nathan Sheldon [email protected]

Dataset Creators:
Name: Cecilia M. Howard
Email: [email protected]
Institution: University of Michigan Department of Earth and Environmental Sciences
ORCID: https://orcid.org/0000-0001-7293-162X

Name: Nathan D. Sheldon
Email: [email protected]
Institution: University of Michigan Department of Earth and Environmental Sciences
ORCID: https://orcid.org/0000-0003-3371-0036

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

Research Overview:
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.
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.

Methodology:
We compiled a dataset of microbialites in the Archean and Paleoproterozoic from existing literature starting from a set of review papers and expanding from their references using Web of Science, which we also used to search for additional microbialite occurrences independently. For each entry, we identified the depositional unit to the formation level, age (as geologic time period and as a numeric age), country, continent, type(s) of microbialite (stromatolite, oncolite, thrombolite, microbially induced sedimentary structure (MISS)), broad (marine, tidal, or terrestrial) and specific depositional environments, and the approximate geographic location. Where multiple depositional environments are evidenced within a single formation, one entry was counted for each. We counted microbialites that were formed in subtidal environments with no noted shallower deposition as marine due to the lack of regular subaerial exposure in subtidal environments and the fact that older literature did not always make a clear distinction between the two. “Tidal” is used for units described as intertidal, supratidal, mudflats, lagoons, or sabkhas, and “terrestrially influenced” includes terrestrial units as well as tidal units and epeiric seas, as the latter two categories would be expected to have high inputs of terrigenous materials. When age, depositional environment, or biogenicity were currently or previously contested, we attempted to identify the most current consensus, and uncertainty is noted in the dataset. The variable precision of dating creates a source of error, particularly for units only described in older literature. It is possible that some units were erroneously included or excluded from the dataset due to imprecise or uncertain dating along the Paleo/Mesoproterozoic boundary. While the supplemental data includes some references in languages other than English, those sources were generally found through English literature and used to gather more in-depth information. Thus, it is possible that some additional formations were missed due to language barriers.

Files contained here:
Dataset filename: ArcheanPaleoproterozoic_Microbialites_Data.xlsx
Dataset description: Spreadsheet of Archean and Paleoproterozoic microbialite occurrences. Includes geologic time period, country, continent, stratigraphic unit, types and subtypes of microbialites present, broad depositional environment, all associated depositional environments, age (in Ma), approximate latitude and longitude, a list of sources and their DOIs where available, and additional notes on entries. First tab of the file is the dataset, second tab of the file is a glossary explaining the columns. "NA" is used to denote cells without relevant data.

Dataset filename: ArcheanPaleoproterozoic_Microbialites_Citations.txt
Dataset description: Text file with citations for the data set. Citations are in alphabetical order.

Related publication(s):
Howard, C.M. (2025). Unraveling Records of Time and Environment in Microbial Ecosystems from the Archean to Today (Ph.D. Dissertation). University of Michigan.
Howard, C.M. and Sheldon, N.D. (in prep). Microbialite Niches across the Archean and Paleoproterozoic.

Use and Access:
This data set is made available under a Creative Commons Attribution 4.0 International license (CC BY 4.0).

To Cite Data:
Howard, C.M. and Sheldon, N.D. (2025). Microbialite Occurrence Data for the Archean and Paleoproterozoic [Data set]. University of Michigan - Deep Blue Data.