scholarly journals Implications of a 3.472–3.333 Gyr-old subaerial microbial mat from the Barberton greenstone belt, South Africa for the UV environmental conditions on the early Earth

2006 ◽  
Vol 361 (1476) ◽  
pp. 2261-2261 ◽  
Author(s):  
Frances Westall ◽  
Cornel E.J de Ronde ◽  
Gordon Southam ◽  
Nathalie Grassineau ◽  
Maggy Colas ◽  
...  
Keyword(s):  
South Africa ◽  
Environmental Conditions ◽  
Greenstone Belt ◽  
Microbial Mat ◽  
Early Earth ◽  
Barberton Greenstone Belt

scholarly journals Implications of a 3.472–3.333 Gyr-old subaerial microbial mat from the Barberton greenstone belt, South Africa for the UV environmental conditions on the early Earth

2006 ◽  
Vol 361 (1474) ◽  
pp. 1857-1876 ◽  
Author(s):  
Frances Westall ◽  
Cornel E.J de Ronde ◽  
Gordon Southam ◽  
Nathalie Grassineau ◽  
Maggy Colas ◽  
...  
Keyword(s):  
Uv Radiation ◽  
Greenstone Belt ◽  
Extracellular Polymeric Substances ◽  
Life Forms ◽  
Microbial Mat ◽  
Survival Strategies ◽  
Radiation Environment ◽  
Early Earth ◽  
Gene Repair ◽  
Barberton Greenstone Belt

Modelling suggests that the UV radiation environment of the early Earth, with DNA weighted irradiances of about three orders of magnitude greater than those at present, was hostile to life forms at the surface, unless they lived in specific protected habitats. However, we present empirical evidence that challenges this commonly held view. We describe a well-developed microbial mat that formed on the surface of volcanic littoral sediments in an evaporitic environment in a 3.5–3.3 Ga-old formation from the Barberton greenstone belt. Using a multiscale, multidisciplinary approach designed to strongly test the biogenicity of potential microbial structures, we show that the mat was constructed under flowing water by 0.25 μm filaments that produced copious quantities of extracellular polymeric substances, representing probably anoxygenic photosynthesizers. Associated with the mat is a small colony of rods–vibroids that probably represent sulphur-reducing bacteria. An embedded suite of evaporite minerals and desiccation cracks in the surface of the mat demonstrates that it was periodically exposed to the air in an evaporitic environment. We conclude that DNA-damaging UV radiation fluxes at the surface of the Earth at this period must either have been low (absorbed by CO 2 , H 2 O, a thin organic haze from photo-dissociated CH 4 , or SO 2 from volcanic outgassing; scattered by volcanic, and periodically, meteorite dust, as well as by the upper layers of the microbial mat) and/or that the micro-organisms exhibited efficient gene repair/survival strategies.

Paleomagnetism of 3.5-4.0 Ga zircons from the Barberton Greenstone Belt, South Africa

2021 ◽  
Vol 567 ◽  
pp. 116999
Author(s):  
Roger R. Fu ◽  
Nadja Drabon ◽  
Michael Wiedenbeck ◽  
Alec R. Brenner ◽  
Donald R. Lowe ◽  
...  
Keyword(s):  
South Africa ◽  
Greenstone Belt ◽  
Barberton Greenstone Belt

scholarly journals Paleoarchean sulfur cycling: Multiple sulfur isotope constraints from the Barberton Greenstone Belt, South Africa

2015 ◽  
Vol 267 ◽  
pp. 311-322 ◽  
Author(s):  
Alice Montinaro ◽  
Harald Strauss ◽  
Paul R.D. Mason ◽  
Desiree Roerdink ◽  
Carsten Münker ◽  
...  
Keyword(s):  
South Africa ◽  
Greenstone Belt ◽  
Sulfur Isotope ◽  
Sulfur Cycling ◽  
Barberton Greenstone Belt
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