Early life on Earth and analogies to Mars
International audience The evidence for early life and its initial evolution on Earth is linked intimately with the geological evolution of the early Earth. The environment of the early Earth would be considered extreme by modern standards: hot (50–80°C), volcanically and hydrothermally active, anox...
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ftunivnantes:oai:HAL:hal-00115174v1 2023-05-15T16:29:58+02:00 Early life on Earth and analogies to Mars Westall, Frances Centre de biophysique moléculaire (CBM) Université d'Orléans (UO)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS) 2005 https://hal.science/hal-00115174 https://doi.org/10.1007/978-3-540-31538-4_3 en eng HAL CCSD Spinger, Berlin info:eu-repo/semantics/altIdentifier/doi/10.1007/978-3-540-31538-4_3 hal-00115174 https://hal.science/hal-00115174 doi:10.1007/978-3-540-31538-4_3 Water on Mars (Advances in astrobiology and biogeophysics) https://hal.science/hal-00115174 Water on Mars (Advances in astrobiology and biogeophysics), Spinger, Berlin, pp.45-64, 2005, ⟨10.1007/978-3-540-31538-4_3⟩ [CHIM]Chemical Sciences [SDU]Sciences of the Universe [physics] info:eu-repo/semantics/bookPart Book sections 2005 ftunivnantes https://doi.org/10.1007/978-3-540-31538-4_3 2023-02-08T10:45:31Z International audience The evidence for early life and its initial evolution on Earth is linked intimately with the geological evolution of the early Earth. The environment of the early Earth would be considered extreme by modern standards: hot (50–80°C), volcanically and hydrothermally active, anoxic, high UV flux, and a high flux of extraterrestrial impacts. Habitats for life were more limited until continent-building processes resulted in the formation of stable cratons with wide, shallow, continental platforms in the Mid-Late Archaean. Unfortunately there are no records of the first appearance of life and the earliest isotopic indications of the existence of organisms fractionating carbon in ∼3.8 Ga rocks from the Isua greenstone belt in Greenland are tenuous. Well-preserved microfossils and microbial mats (in the form of tabular and domical stromatolites) occur in 3.5–3.3 Ga, Early Archaean, sedimentary formations from the Barberton (South Africa) and Pilbara (Australia) greenstone belts. They document life forms that show a relatively advanced level of evolution. Microfossil morphology includes filamentous, coccoid, rod and vibroid shapes. Colonial microorganisms formed biofilms and microbial mats at the surfaces of volcaniclastic and chemical sediments, some of which created (small) macroscopic microbialites such as stromatolites. Anoxygenic photosynthesis may already have developed. Carbon, nitrogen and sulphur isotopes ratios are in the range of those for organisms with anaerobic metabolisms, such as methanogenesis, sulphate reduction and photosynthesis. Life was apparently distributed widely in shallow-water to littoral environments, including exposed, evaporitic basins and regions of hydrothermal activity. Biomass in the early Archaean was restricted owing to the limited amount of energy that could be produced by anaerobic metabolisms. Microfossils resembling oxygenic photosynthesisers, such as cyanobacteria, probably first occurred in the later part of the Mid Archaean (∼2.9 Ga), concurrent with ... Book Part Greenland Université de Nantes: HAL-UNIV-NANTES Greenland 45 64 |
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Université de Nantes: HAL-UNIV-NANTES |
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English |
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[CHIM]Chemical Sciences [SDU]Sciences of the Universe [physics] |
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[CHIM]Chemical Sciences [SDU]Sciences of the Universe [physics] Westall, Frances Early life on Earth and analogies to Mars |
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[CHIM]Chemical Sciences [SDU]Sciences of the Universe [physics] |
description |
International audience The evidence for early life and its initial evolution on Earth is linked intimately with the geological evolution of the early Earth. The environment of the early Earth would be considered extreme by modern standards: hot (50–80°C), volcanically and hydrothermally active, anoxic, high UV flux, and a high flux of extraterrestrial impacts. Habitats for life were more limited until continent-building processes resulted in the formation of stable cratons with wide, shallow, continental platforms in the Mid-Late Archaean. Unfortunately there are no records of the first appearance of life and the earliest isotopic indications of the existence of organisms fractionating carbon in ∼3.8 Ga rocks from the Isua greenstone belt in Greenland are tenuous. Well-preserved microfossils and microbial mats (in the form of tabular and domical stromatolites) occur in 3.5–3.3 Ga, Early Archaean, sedimentary formations from the Barberton (South Africa) and Pilbara (Australia) greenstone belts. They document life forms that show a relatively advanced level of evolution. Microfossil morphology includes filamentous, coccoid, rod and vibroid shapes. Colonial microorganisms formed biofilms and microbial mats at the surfaces of volcaniclastic and chemical sediments, some of which created (small) macroscopic microbialites such as stromatolites. Anoxygenic photosynthesis may already have developed. Carbon, nitrogen and sulphur isotopes ratios are in the range of those for organisms with anaerobic metabolisms, such as methanogenesis, sulphate reduction and photosynthesis. Life was apparently distributed widely in shallow-water to littoral environments, including exposed, evaporitic basins and regions of hydrothermal activity. Biomass in the early Archaean was restricted owing to the limited amount of energy that could be produced by anaerobic metabolisms. Microfossils resembling oxygenic photosynthesisers, such as cyanobacteria, probably first occurred in the later part of the Mid Archaean (∼2.9 Ga), concurrent with ... |
author2 |
Centre de biophysique moléculaire (CBM) Université d'Orléans (UO)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS) |
format |
Book Part |
author |
Westall, Frances |
author_facet |
Westall, Frances |
author_sort |
Westall, Frances |
title |
Early life on Earth and analogies to Mars |
title_short |
Early life on Earth and analogies to Mars |
title_full |
Early life on Earth and analogies to Mars |
title_fullStr |
Early life on Earth and analogies to Mars |
title_full_unstemmed |
Early life on Earth and analogies to Mars |
title_sort |
early life on earth and analogies to mars |
publisher |
HAL CCSD |
publishDate |
2005 |
url |
https://hal.science/hal-00115174 https://doi.org/10.1007/978-3-540-31538-4_3 |
geographic |
Greenland |
geographic_facet |
Greenland |
genre |
Greenland |
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Greenland |
op_source |
Water on Mars (Advances in astrobiology and biogeophysics) https://hal.science/hal-00115174 Water on Mars (Advances in astrobiology and biogeophysics), Spinger, Berlin, pp.45-64, 2005, ⟨10.1007/978-3-540-31538-4_3⟩ |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.1007/978-3-540-31538-4_3 hal-00115174 https://hal.science/hal-00115174 doi:10.1007/978-3-540-31538-4_3 |
op_doi |
https://doi.org/10.1007/978-3-540-31538-4_3 |
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45 |
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64 |
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