Archean* fenestrate microbial communities created
complex structures that reflect both the behavior of bacteria in the community
as well as environmental conditions. Results
suggest that two microbial communities with different behaviors coexisted in close proximity
and affected local calcite precipitation
differently. Current work focuses on geochemically characterizing the remnant
organic matter and encasing calcite cements.
Preliminary results suggest a metabolic influence on carbonate precipitation
from one of the communities but not the other. We are also working on reconstructing and visualizing the 3D geometry of these microbializes using software developed by KeckCAVES. For examples of 3D microbialites, see my YouTube videos below.
The polished slab on the left shows the complex geometry of the microbial
communities (black) and the abundance of void-filling calcite cements (grey
and white). Some of the microbial communities grew up vertically whereas
others formed more common, horizontal and draping mats. The grey calcite
cements consist of herringbone calcite.
The scale bar at the bottom right is 1 cm long.
Videos of Microbialites
For this publication:
Billen, Magali I., Oliver Kreylos, Bernd Hamann, Margarete Jadamec, Louise H. Kellogg, Oliver Staadt, and Dawn Y. Sumner, 2008. A geoscience perspective on immersive 3D gridded data visualization. Computers and Geosciences, v. 34:9, DOI: 10.1016/j.cageo.2007.11.009 Link
A video that's more fun:
Publications on Archean Microbial Structures:
Schroeder, S., N. J. Beukes, and D. Y. Sumner
Microbialite-sediment interactions on the slope of the Campbellrand carbonate platform (Neoarchean, South Africa). Precambrian Research. (Accepted)
Waldbauer, Jacob R., Laura S. Sherman, Dawn Y. Sumner, and Roger E. Summons
Late Archean molecular fossils from the Transvaal Supergroup record the antiquity of microbial diversity and aerobiosis. Precambrian Research. (Accepted)
Murphy*, Megan, and Dawn Y. Sumner, 2008. Abstract
Variations in Neoarchean microbialite morphologies: Clues to controls on microbialite morphologies through time. Sedimentology, DOI: 10.1111/j.1365-3091.2007.00942.x
Murphy*, Megan, and Dawn Y. Sumner, 2007. Abstract
Tube structures of probable microbial origin in the Neoarchean Carawine Dolomite, Hamersley Basin, Western Australia. Geobiology, DOI: 10.1111/j.1472-4669.2007.00114.x
Carbonate precipitation and oxygen stratification in late Archean seawater as deduced from facies and stratigraphy of the Gamohaan and Frisco formations, Transvaal Supergroup, South Africa. American Journal of Science, v. 297, p. 455-487.
Sumner, Dawn Y., 1997. Abstract (at the Palaios site)
Late Archean calcite-microbe interactions: Two morphologically distinct
microbial communities that affected calcite nucleation differently. Palaios, v. 12, p. 302-318.