Terrestrial Bacterial Mats During PaleoProterozoic 200 Million Years After Onset of Great Oxidation Event

Evidence for 2.0 Ga continental microbial mats in a paleodesert setting

Authors:

1. Edward L. Simpson (a)
2. Elizabeth Heness (a)
3. Adam Bumby (b)
4. Patrick G. Eriksson (b)
5. Kenneth A. Eriksson (c)
6. Hannah L. Hilbert-Wolf (d)
7. Sarah Linnevelt (b)
8. H. Fitzgerald Malenda (a)
9. Tshepiso Modungwa (b)
10. O.J. Okafor (b)

Affiliations:

a. Department of Physical Sciences, Kutztown University of Pennsylvania, Kutztown PA 19530, USA

b. Department of Geology, University of Pretoria, Pretoria 0002, South Africa

c. Department of Geosciences, Virginia Tech, Blacksburg,VA 24061, USA

d. School of Earth and Environmental Sciences, James Cook University, Townsville, Qld 4811, Australia

Abstract:

Early evolved microbial communities characterized the initial biological invasion of Precambrian continental landscapes. In modern arid settings, microbial mats and biological soil crusts are well-developed and stabilize sediment. The Paleoproterozoic Makgabeng Formation in South Africa is one of the oldest and best preserved, dryland systems on Earth. Six types of microbial mat-related structures are now recognized within these depositional systems. This paper presents three newly discovered structures that include tufted microbial mat, biological soil crusts, and gas-escape features, in addition to three previously documented structures that include roll up features, sand cracks, and wrinkled features. These discoveries demonstrate that microbial communities were well-established and inhabited diverse continental settings by 2.0 Ga, approximately 200 million years after the onset of the Great Oxidation Event.