Structures resembling remarkably preserved bacterial and cyanobacterial microfossils from about 3,465-million-year-old Apex cherts of the Warrawoona Group in Western Australia currently provide the oldest morphological evidence for life on Earth and have been taken to support an early beginning for oxygen-producing photosynthesis. Eleven species of filamentous prokaryote, distinguished by shape and geometry, have been put forward as meeting the criteria required of authentic Archaean microfossils, and contrast with other microfossils dismissed as either unreliable or unreproducible. These structures are nearly a billion years older than putative cyanobacterial biomarkers, genomic arguments for cyanobacteria, an oxygenic atmosphere and any comparably diverse suite of microfossils. Here we report new research on the type and re-collected material, involving mapping, optical and electron microscopy, digital image analysis, micro-Raman spectroscopy and other geochemical techniques. We reinterpret the purported microfossil-like structure as secondary artefacts formed from amorphous graphite within multiple generations of metalliferous hydrothermal vein chert and volcanic glass. Although there is no support for primary biological morphology, a Fischer--Tropsch-type synthesis of carbon compounds and carbon isotopic fractionation is inferred for one of the oldest known hydrothermal systems on Earth.

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Are there petroleum resources in Antarctica?, by John C. Behrendt. in pre-break-up Triassic strata, to intracontinental rocks of the Beacon Supergroup and Ferrar. Group. These flat-lying rocks are especially wide-in the Beardmore Glacier area locality 69, fig. in the Devonian through Jurassic Beacon Super-. PaleoTerra: Devonian Lithological Database: Sources A-G basin antarctica terra: Topics by E-print Network-OSTI The Beacon Supergroup Devonian-Triassic and. Ferrar Group Jurassic in the Beardmore Glacier area, Antarctica. Ant. Res. Ser., 36:339-428. Barrett, P.J. Summary: Shetland Islands and perhaps the Antarctica Peninsula region. Pole in December 1986 by the Radio Physics Research group at Bell Laboratories. Petroleum and Mineral Resources of Antarctica Antarctic Region. sequence of g~erally flat-lying rocks, the Beacon Supergroup, which are composed of shallow marine-non-marine quartzose sediments of Devonian age raylor Group, unconformably overlain by Collinson, J.W. & Isbell, lL., 1986-Permian-Triassic sedimentology of the Beardmore Glacier region. These rocks record ordovician Sm-Nd ages, Devonian Rb-Sr ages, and. 25 Figure 3.1 Mafic schist belonging to the Northern Group on west shore of Brents mouw Peak in the Beardmore Glacier region of Antarctica in conjunction with in the

Carbon isotopes through 6km of fully cored drill holes in 1.7 to 1.5 Ga carbonates of the Mount Isa and McArthur basins, Australia (which host the earliest known eukaryote biomarkers) provide the most comprehensive and best-dated delta 13C stratigraphy yet obtained from such ancient rocks. Both basins reveal remarkably stable temporal delta 13C trends (mean of -0.6% +/- 2% PDB [Peedee belemnite]) and confirm the impression of delta 13C stasis between 2.0 and 1.0 Ga, which, together with other evidence, suggest a prolonged period of stability in crustal dynamics, redox state of surface environments, and planetary climate. This delta 13C stasis is consistent with great stability in the carbon cycle controlled, we suggest, by P limitation of primary productivity. Recent evidence shows that P depletion is a major factor in obligate associations between photosymbionts and host cells. We argue that a billion years of stability in the carbon and nutrient cycles may have been the driving force that propelled prokaryotes toward photosymbiosis and the emergence of the autotrophic eukaryote cell.