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The disappearance of iron formations from the geological record approximately 1.8 billion years (Gyr) ago was the consequence of rising oxygen levels in the atmosphere starting 2.45-2.32 Gyr ago. It marks the end of a 2.5-Gyr period dominated by anoxic and iron-rich deep oceans. However, despite rising oxygen levels and a concomitant increase in marine(More)
Microbial life inhabits deeply buried marine sediments, but the extent of this vast ecosystem remains poorly constrained. Here we provide evidence for the existence of microbial communities in ~40° to 60°C sediment associated with lignite coal beds at ~1.5 to 2.5 km below the seafloor in the Pacific Ocean off Japan. Microbial methanogenesis was indicated by(More)
Hydrogen-lean kerogen (atomic H/C < 0.46) isolated from the 3.4 Ga Strelley Pool Chert in the North Pole area, Pilbara Craton, Western Australia, were studied by vibrational spectroscopy (Fourier transform infrared (FTIR) spectroscopy and Raman spec-troscopy), nuclear magnetic resonance spectroscopy (solid state 13 C NMR spectroscopy), catalytic(More)
Geochemical data from ancient sedimentary successions provide evidence for the progressive evolution of Earth's atmosphere and oceans. Key stages in increasing oxygenation are postulated for the Palaeoproterozoic era (∼2.3 billion years ago, Gyr ago) and the late Proterozoic eon (about 0.8 Gyr ago), with the latter implicated in the subsequent metazoan(More)
The 7th century ship-burial at Sutton Hoo is famous for the spectacular treasure discovered when it was first excavated in 1939. The finds include gold and garnet jewellery, silverware, coins and ceremonial armour of broad geographical provenance which make a vital contribution to understanding the political landscape of early medieval Northern Europe.(More)
The interaction of microbes and metals is widely assumed to have occurred in surface or very shallow subsurface environments. However new evidence suggests that much microbial activity occurs in the deep subsurface. Fluvial, lacustrine and aeolian ‘red beds’ contain widespread centimetre-scale reduction spheroids in which a pale reduced spheroid in(More)
Introduction: The presence of sulfates on the surface of Mars was indicated by a strong Mg-S correlation in the fluorescence data obtained by the Viking landers [1]. Sulfates were subsequently identified as being present in the soil at the Pathfinder landing site at a concentration of ~ 10 % MgSO4 [2]. Data from the Opportunity rover indicates that sulfates(More)
Introduction: The response of organic matter to impact events is of widespread interest for what it tells us about the likelihood of survival of life and/or fossilized biological signatures [1,2,3] following impacts. This is relevant to the history of life on Earth, and to our exploration of other solar system bodies, including Mars. The Tertiary Haughton(More)
Mineral crusts: Mineral crusts are a widely developed feature at the rock or sediment surface, wherever there is a flux of water. They occur in all climatic zones, from tropical to polar desert, although their chemistry and morphology varies with surface hydrol-ogy, temperature and substrate. Thus the range of deposits includes duricrusts (calcrete,(More)