Rapid emergence of life shown by discovery of 3,700-million-year-old microbial structures

  title={Rapid emergence of life shown by discovery of 3,700-million-year-old microbial structures},
  author={Allen P. Nutman and Vickie C. Bennett and Clark R.L. Friend and Martin J. Van Kranendonk and Allan r. Chivas},
Biological activity is a major factor in Earth’s chemical cycles, including facilitating CO2 sequestration and providing climate feedbacks. Thus a key question in Earth’s evolution is when did life arise and impact hydrosphere–atmosphere–lithosphere chemical cycles? Until now, evidence for the oldest life on Earth focused on debated stable isotopic signatures of 3,800–3,700 million year (Myr)-old metamorphosed sedimentary rocks and minerals from the Isua supracrustal belt (ISB), southwest… Expand
Reassessing evidence of life in 3,700-million-year-old rocks of Greenland
Three-dimensional analysis of the morphology and orientation of the structures within the context of host rock fabrics, combined with texture-specific analyses of major and trace element chemistry, show that the ‘stromatolites’ are more plausibly interpreted as part of an assemblage of deformation structures formed in carbonate-altered metasediments long after burial. Expand
Microbial life and biogeochemical cycling on land 3,220 million years ago
The colonization of emergent continental landmass by microbial life was an evolutionary step of paramount importance in Earth history. Here we report direct fossil evidence for life on land 3,220Expand
Stromatolites as geochemical archives to reconstruct microbial habitats through deep time: Potential and pitfalls of novel radiogenic and stable isotope systems
Abstract Understanding the origin and evolution of life on Earth and potentially other planets in our solar system is of fundamental interest for humanity. For the longest time in Earth's history,Expand
Morpho- and Chemo-Fossil Evidence of Early Life
This chapter summarizes what is known about the timing of the emergence of life on Earth from the morpho- and chemo-fossil (chemical and isotopic signals remaining from the decomposition of livingExpand
Geology: Evidence of life in Earth's oldest rocks
This report describes metamorphosed stromatolites deposited around 3,700 million years ago in what is now Greenland, which is more than 200 million years older than the previous record-holders for earliest-known fossils, so these strom atolites rank as the Earth's earliest fossils by some margin. Expand
Paleo-Rock-Hosted Life on Earth and the Search on Mars: A Review and Strategy for Exploration
Findings suggest that rock-hosted life would have been more likely to emerge and be preserved in a martian context, and outline a Mars exploration strategy that targets subsurface life and scales spatially, focusing initially on identifying rocks with evidence for groundwater flow and low-temperature mineralization, then identifying redox and permeability interfaces preserved within rock outcrops. Expand
Importance of Prokaryotes in the Functioning and Evolution of the Present and Past Geosphere and Biosphere
On a volcanic and anaerobic planet characterized by abundant hydrothermal activity, physicochemical gradients and disequilibria at the local scale would have been fundamental for the emergence ofExpand
Metabolic specializations within a bacterial community to create living rocks
It is proposed that abundance of extracellular alkaline phosphatases, in combination with the absence of transport regulatory enzymes, may lead to the precipitation of phosphatic deposits within these stromatolites, and it is concluded that the cumulative effect of several conserved bacterial species drives accretion in these two strom atolite formations. Expand
The Martian subsurface as a potential window into the origin of life
Few traces of Earth’s geologic record are preserved from the time of life’s emergence, over 3,800 million years ago. Consequently, what little we understand about abiogenesis — the origin of life onExpand
Signatures of early microbial life from the Archean (4 to 2.5 Ga) eon
Abstract The Archean era (4 to 2.5 billion years ago, Ga) yielded rocks that include the oldest conclusive traces of life as well as many controversial occurrences. Carbonaceous matter is found inExpand


Evidence for life on Earth before 3,800 million years ago
IT is unknown when life first appeared on Earth. The earliest known microfossils (˜3,500 Myr before present) are structurally complex, and if it is assumed that the associated organisms required aExpand
Reassessing the evidence for the earliest traces of life
It is shown that graphite occurs abundantly in secondary carbonate veins in the ISB that are formed at depth in the crust by injection of hot fluids reacting with older crustal rocks (metasomatism); these metasomatic rocks, which clearly lack biological relevance, were earlier thought to be of sedimentary origin. Expand
Carbon isotope geochemistry of the 3.7 × 109-yr-old Isua sediments, West Greenland: implications for the Archaean carbon and oxygen cycles
One hundred and twenty-four carbonate samples from the meta-sedimentary sequence of the 3.7 × 109 yr old Isua supracrustal belt (W-Greenland) have yielded a δ13Ccarb average of −2.5 ± 1.7%. vs PDBExpand
Stromatolite reef from the Early Archaean era of Australia
A multi-kilometre-scale palaeontological and palaeoenvironmental study of the Strelley Pool Chert, in which the first morphotype-specific analysis of the structures within their palaioenvironment and refute contemporary abiogenic hypotheses for their formation are undertaken. Expand
Microbial mediation as a possible mechanism for natural dolomite formation at low temperatures
DOLOMITE (CaMg(CO3)2) is a common carbonate mineral which is found in much greater abundance in ancient rocks than in modern carbonate environments. Why this is so remains a mystery. Over the past 30Expand
Geological and trace element evidence for a marine sedimentary environment of deposition and biogenicity of 3.45 Ga stromatolitic carbonates in the Pilbara Craton, and support for a reducing Archaean ocean
Bedded carbonate rocks from the 3.45 Ga Warrawoona Group, Pilbara Craton, contain structures that have been regarded either as the oldest known stromatolites or as abiotic hydrothermal deposits. WeExpand
Seawater-like trace element signatures (REE + Y) of Eoarchaean chemical sedimentary rocks from southern West Greenland, and their corruption during high-grade metamorphism
Modern chemical sediments display a distinctive rare earth element + yttrium (REE + Y) pattern involving depleted LREE, positive La/La*SN, Eu/Eu*SN, and YSN anomalies (SN = shale normalised) that isExpand
≥3700 Ma pre-metamorphic dolomite formed by microbial mediation in the Isua supracrustal belt (W.Greenland): Simple evidence for early life?
Chemical (meta)sedimentary rocks in the amphibolite facies ≥3700 Ma Isua supracrustal belt (W. Greenland) are mostly strongly deformed, so there is only a small chance of the survival of featuresExpand
An abiotic model for stromatolite morphogenesis
This work deduces, from both the microscopic textures and the fractal dimension, a purely abiotic dynamical model of stromatolite surface growth that combines chemical precipitation on the growing interface, fallout and diffusive rearrangement of suspended sediment, and uncorrelated random noise. Expand
Stromatolites 3,400–3,500 Myr old from the North Pole area, Western Australia
Stromatolites are the least controversial evidence of early life; they are organosedimentary structures resulting from the growth and metabolic activity of microorganisms1. Before this report,Expand