title: Evidence for early life in Earth's oldest hydrothermal vent precipitates.
abstract: Although it is not known when or where life on Earth began, some of the earliest habitable environments may have been submarine-hydrothermal vents. Here we describe putative fossilized microorganisms that are at least 3,770 million and possibly 4,280 million years old in ferruginous sedimentary rocks, interpreted as seafloor-hydrothermal vent-related precipitates, from the Nuvvuagittuq belt in Quebec, Canada. These structures occur as micrometre-scale haematite tubes and filaments with morphologies and mineral assemblages similar to those of filamentous microorganisms from modern hydrothermal vent precipitates and analogous microfossils in younger rocks. The Nuvvuagittuq rocks contain isotopically light carbon in carbonate and carbonaceous material, which occurs as graphitic inclusions in diagenetic carbonate rosettes, apatite blades intergrown among carbonate rosettes and magnetite-haematite granules, and is associated with carbonate in direct contact with the putative microfossils. Collectively, these observations are consistent with an oxidized biomass and provide evidence for biological activity in submarine-hydrothermal environments more than 3,770 million years ago.
authors.affiliation: London Centre for Nanotechnology, 17-19 Gordon Street, London WC1H 0AH, UK.|Department of Earth Sciences, University College London, Gower Street, London WC1E 6BT, UK.
authors.forename: Matthew S
authors.initials: MS
authors.lastname: Dodd
authors.affiliation: London Centre for Nanotechnology, 17-19 Gordon Street, London WC1H 0AH, UK.|Department of Earth Sciences, University College London, Gower Street, London WC1E 6BT, UK.
authors.forename: Dominic
authors.initials: D
authors.lastname: Papineau
authors.affiliation: Geological Survey of Norway, Leiv Eirikssons vei 39, 7040 Trondheim, Norway.
authors.forename: Tor
authors.initials: T
authors.lastname: Grenne
authors.affiliation: U.S. Geological Survey, National Center, MS 954, Reston, Virginia 20192, USA.
authors.forename: John F
authors.initials: JF
authors.lastname: Slack
authors.affiliation: Department of Earth Sciences, University College London, Gower Street, London WC1E 6BT, UK.
authors.forename: Martin
authors.initials: M
authors.lastname: Rittner
authors.affiliation: Centre for Exploration Targeting, The University of Western Australia, 35 Stirling Highway, Crawley, Western Australia 6009, Australia.
authors.forename: Franco
authors.initials: F
authors.lastname: Pirajno
authors.affiliation: Department of Earth and Environmental Sciences, University of Ottawa, Ottawa, K1N 6N5, Canada.
authors.forename: Jonathan
authors.initials: J
authors.lastname: O'Neil
authors.affiliation: School of Earth and Environment, University of Leeds, Leeds LS2 9JT, UK.
authors.forename: Crispin T S
authors.initials: CT
authors.lastname: Little
mesh_terms: D018533:Biomass; D002247:Carbon Isotopes; D002254:Carbonates / Q000737:chemistry; D005290:Ferric Compounds / Q000737:chemistry; D052203:Ferrosoferric Oxide / Q000737:chemistry; D005580:Fossils; D019015:Geologic Sediments / Q000737:chemistry; D060086:Hydrothermal Vents / Q000382:microbiology*; D019369:Life; D000069497:Origin of Life; D011792:Quebec; D013997:Time Factors
chemical_list: D002247:Carbon Isotopes; D002254:Carbonates; D005290:Ferric Compounds; C000499:ferric oxide; D052203:Ferrosoferric Oxide