Drilling Earth's early surface environments: Moodies Group, Barberton Greenstone Belt, South Africa
Final Report Abstract
The search for traces of life on other planets has its parallels to the search for the beginning of life on Earth itself because it teaches us in which environments we should look for suspicious shapes and sizes of biological activity. I t is therefore encouraging that the oldest well-preserved shallow-water strata, preserved in a mountain range in South Africa, show evidence that microbial life not only existed microscopically and in isolated patches but already occupied tracts that are mappable and continuous over several km. The sandstone strata studied in the Barberton Greenstone Belt by Christoph Heubeck of the Freie Universität Berlin are densely permeated by abundant carbon-rich laminations. These wavy-crinkly bands, interpreted as remains of microbial mats, apparently interacted with considerable currents that transported sand and gravel in a coastline or tidal environment. The laminations show deformation patterns that suggest a flexible but sturdy mechanical behavior, a surface morphology of at least a few cm, and very rapid growth. In addition, the microbial mats were apparently cohesive enough to trap fluids and gases, occasionally giving rise to small sand volcanoes. The mechanical strength of the biomats was possibly derived from very early silicification, similar to what can be observed today in active hot spring fields. Thus, shallow-water environments at elevated temperatures may constitute a promising and readily detectable habitat in the search for early life.
Publications
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2009. An early ecosystem of Archean tidal microbial mats (Moodies Group. South Africa: ca. 3.2 Ga): Geologische Vereinigung Annual Meeting. Abstracts Volume, October 2009. Göttinqen: p. 56
Heubeck. C .
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2009a An early ecosystem of Archean tidal microbial mats (Moodies Group. South Africa, ca. 3.2 Ga): Geology, 37, p. 931 - 934
Heubeck, C
