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 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… 

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.

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 3,220

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 living

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.

Geology: Evidence of life in Earth's oldest rocks

  • A. Allwood
  • Geology, Environmental Science
  • 2016
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.

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 of

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.

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 on



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 a

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.

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.

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 30

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 is

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. We

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.

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,

Waves and weathering at 3.7 Ga: Geological evidence for an equitable terrestrial climate under the faint early Sun

Chemical sedimentary rocks such as banded iron formation (BIF) and pillow basalts are persistent features of the oldest volcanic and sedimentary record by 3.8–3.7 Ga, and are direct evidence for