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Veizer J. Carbonates and Ancient Oceans: Isotopic and Chemical Record on Time Scales of 107
-109
Years. ACTA ACUST UNITED AC 2013. [DOI: 10.1029/gm032p0595] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/20/2023]
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Photochemical Consequences of Enhanced CO2
Levels in Earth's Early Atmosphere. ACTA ACUST UNITED AC 2013. [DOI: 10.1029/gm032p0612] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/25/2023]
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Abstract
This paper uses arguments of geochemical mass balance to arrive at an estimate of the partial pressure of carbon dioxide in the terrestrial atmosphere very early in earth history. It appears that this partial pressure could have been as large as 10 bars. This large estimate depends on two key considerations. First, volatiles were driven out of the interior of the earth during the course of earth accretion or very shortly thereafter. This early degassing was a consequence of rapid accretion,which gave the young earth a hot and rapidly convecting interior. Second, the early earth lacked extensive, stable continental platforms on which carbon could be stored in the form of carbonate minerals for geologically significant periods of time. In the absence of continental platforms on the early earth, the earth's carbon must have been either in the atmosphere or ocean or in the form of shortlived sedimentary deposits on ephemeral sea floor.
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Affiliation(s)
- J C Walker
- Department of Atmospheric and Oceanic Science, The University of Michigan, Ann Arbor 48109, USA
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Grassineau NV, Nisbet EG, Bickle MJ, Fowler CM, Lowry D, Mattey DP, Abell P, Martin A. Antiquity of the biological sulphur cycle: evidence from sulphur and carbon isotopes in 2700 million-year-old rocks of the Belingwe Belt, Zimbabwe. Proc Biol Sci 2001; 268:113-9. [PMID: 11209879 PMCID: PMC1088579 DOI: 10.1098/rspb.2000.1338] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Sulphur and carbon isotopic analyses on small samples of kerogens and sulphide minerals from biogenic and non-biogenic sediments of the 2.7 x 10(9) years(Ga)-old Belingwe Greenstone Belt (Zimbabwe) imply that a complex biological sulphur cycle was in operation. Sulphur isotopic compositions display a wider range of biological fractionation than hitherto reported from the Archaean. Carbon isotopic values in kerogen record fractionations characteristic of rubisco activity methanogenesis and methylotrophy and possibly anoxygenic photosynthesis. Carbon and sulphur isotopic fractionations have been interpreted in terms of metabolic processes in 2.7 Ga prokaryote mat communities, and indicate the operation of a diverse array of metabolic processes. The results are consistent with models of early molecular evolution derived from ribosomal RNA.
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Affiliation(s)
- N V Grassineau
- Department of Geology, Royal Holloway, University of London, Surrey, UK.
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Eriksson KA. Crustal growth, surface processes, and atmospheric evolution on the early Earth. ACTA ACUST UNITED AC 1995. [DOI: 10.1144/gsl.sp.1995.095.01.02] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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Chapter 12 The Archean Atmosphere: Its Composition and Fate. ACTA ACUST UNITED AC 1994. [DOI: 10.1016/s0166-2635(08)70230-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/25/2023]
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Des Marais DJ, Strauss H, Summons RE, Hayes JM. Carbon isotope evidence for the stepwise oxidation of the Proterozoic environment. Nature 1992; 359:605-9. [PMID: 11536507 DOI: 10.1038/359605a0] [Citation(s) in RCA: 95] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The oxidation of the Earth's crust and the increase in atmospheric oxygen early in Earth history have been linked to the accumulation of reduced carbon in sedimentary rocks. Trends in the carbon isotope composition of sedimentary organic carbon and carbonate show that during the Proterozoic aeon (2.5-0.54 Gyr ago) the organic carbon reservoir grew in size, relative to the carbonate reservoir. This increase, and the concomitant release of oxidizing power in the environment, occurred mostly during episodes of global rifting and orogeny.
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Affiliation(s)
- D J Des Marais
- NASA, Ames Research Center, Moffett Field, California 94035
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Schidlowski M. The initiation of biological processes on Earth: summary of empirical evidence. ADVANCES IN SPACE RESEARCH : THE OFFICIAL JOURNAL OF THE COMMITTEE ON SPACE RESEARCH (COSPAR) 1992; 12:143-156. [PMID: 11538134 DOI: 10.1016/0273-1177(92)90168-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
With the currently available geological record at band, the existence of life on this planet as from at least 3.8 Gyr ago seems so firmly established as to be virtually unassailable. Specifically, various disparate lines of evidence have merged to indicate (1) that the surface of the Archaean Earth had hosted prolific microbial ecosystems as is testified by a quasi-continuous record of microbialites ("stromatolites") and associated microfossils of prokaryotic affinity over 3.5, if not 3.8 Gyr of geological history, and (2) that the sedimentary carbon record has preserved the isotopic signature of autotrophic (notably photosynthetic) carbon fixation over the same time span. With the observed enrichment of isotopically light carbon in sedimentary organic matter largely consonant with the bias in favor of 12C during photosynthesis, the mainstream of the carbon isotope record can be best explained as geochemical manifestation of the isotope discriminating properties of the ribulose-1,5-bisphosphate (RuBP) carboxylase reaction of the Calvin cycle suggesting an extreme degree of evolutionary conservatism in the biochemistry of autotrophic carbon fixation. As a consequence, partial biological control of the geochemical carbon cycle was established already during Early Archaean times and fully operative by the time of formation of the Earth's earliest sediments.
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Affiliation(s)
- M Schidlowski
- Max-Planck-Institut fur Chemie (Otto-Hahn-Institut), Mainz, Germany
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Lécuyer C, Fourcade S. Oxygen isotope evidence for multi-stage hydrothermal alteration at a fossil slow-spreading center: the Silurian Trinity ophiolite (California, U.S.A. ). ACTA ACUST UNITED AC 1991. [DOI: 10.1016/0168-9622(91)90023-p] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Derry LA, Keto LS, Jacobsen SB, Knoll AH, Swett K. Sr isotopic variations in Upper Proterozoic carbonates from Svalbard and East Greenland. GEOCHIMICA ET COSMOCHIMICA ACTA 1989; 53:2331-2339. [PMID: 11539779 DOI: 10.1016/0016-7037(89)90355-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
We report initial 87Sr/86Sr values from an Upper Proterozoic carbonate succession from Svalbard and East Greenland. This succession, now tectonically separated into three sequences, is thick, relatively continuous, and well preserved. The relative ages of the samples from within the basin are well constrained by litho-, bio-, and chemostratigraphic techniques. The data from this study and related data from the literature are used to construct a curve of 87Sr/86Sr for Upper Proterozoic seawater. The new data reported in this study substantially improve the isotopic record of Sr in seawater for the period between 650 and 800 Ma. The data indicate that delta 87Sr values of seawater were variable but low (delta 87Sr approximately -500 to -250) between 900 and 650 Ma, and rose rapidly to approximately +30 by 600 Ma. The range of variation of delta 87Sr in seawater during the Riphean-Vendian exceeds the entire range of delta 87Sr in seawater during the Phanerozoic. While variation in the average isotopic composition of Sr delivered to the oceans by rivers can account for some of the observed range, changes in the ratio of submarine hydrothermal flux to river water (continental) flux are responsible for the large variation in seawater Sr isotopic composition. Changes in the continental flux of Sr to the oceans can be related to tectonic factors. Large changes in the hydrothermal flux to river water flux ratio indicated by the data could have significant consequences for the chemistry of the ocean-atmosphere system.
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Affiliation(s)
- L A Derry
- Department of Earth and Planetary Sciences, Harvard University, Cambridge, MA 02138, USA
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Veizer J, Hoefs J, Lowe DR, Thurston PC. Geochemistry of Precambrian carbonates: II. Archean greenstone belts and Archean sea water. GEOCHIMICA ET COSMOCHIMICA ACTA 1989; 53:859-871. [PMID: 11539784 DOI: 10.1016/0016-7037(89)90031-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Carbonate rocks with geological attributes of marine sediments are a minor component of the Archean greenstone belts. Despite their relative scarcity, these rocks are important because they record chemical and isotopic properties of coeval oceans. The greenstones containing such carbonates appear to cluster at approximately 2.8 +/- 0.2 and approximately 3.5 +/- 0.1 Ga ago. The samples for the younger group are from the Abitibi, Yellowknife, Wabigoon (Steep Rock Lake), Michipicoten and Uchi greenstone belts of Canada and the "Upper Greenstones" of Zimbabwe. The older group includes the Swaziland Supergroup of South Africa, Warrawoona Group of Australia and the Sargur marbles of India. Mineralogically, the carbonates of the younger greenstones are mostly limestones and of the older ones, ferroan dolomites (ankerites); the latter with some affinities to hydrothermal carbonates. In mineralized areas with iron ores, the carbonate minerals are siderite +/- ankerite, irrespective of the age of the greenstones. Iron-poor dolomites represent a later phase of carbonate generation, related to post-depositional tectonic faulting. The original mineralogy of limestone sequences appears to have been an Sr-rich aragonite. The Archean carbonates yield near-mantle Sr isotopic values, with (87Sr/86Sr)o of 0.7025 +/- 0.0015 and 0.7031 +/- 0.0008 for younger and older greenstones, respectively. The best preserved samples give delta 13C of +1.5 +/- 1.5% PDB, comparable to their Phanerozoic counterparts. In contrast, the best estimate for delta 18O is -7% PDB. Archean limestones, compared to Phanerozoic examples, are enriched in 16O as well as in Mn2+ and Fe2+, and these differences are not a consequence of post-depositional alteration phenomena. The mineralogical and chemical attributes of Archean carbonates (hence sea water) are consistent with the proposition that the composition of the coeval oceans may have been buffered by a pervasive interaction with the "mantle", that is, with the oceanic crust and the coeval ubiquitous volcanosedimentary piles derived from mantle sources.
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Affiliation(s)
- J Veizer
- Department of Geology, University of Ottawa, Canada
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Basin Analysis in Regionally Metamorphosed and Deformed Early Archean Terrains: Examples from Southern Africa and Western Australia. FRONTIERS IN SEDIMENTARY GEOLOGY 1988. [DOI: 10.1007/978-1-4612-3788-4_19] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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de Wit MJ, Hart RA, Hart RJ. The Jamestown Ophiolite Complex, Barberton mountain belt: a section through 3.5 Ga oceanic crust. ACTA ACUST UNITED AC 1987. [DOI: 10.1016/0899-5362(87)90007-8] [Citation(s) in RCA: 97] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Kasting JF. Theoretical constraints on oxygen and carbon dioxide concentrations in the Precambrian atmosphere. PRECAMBRIAN RESEARCH 1987; 34:205-29. [PMID: 11542097 DOI: 10.1016/0301-9268(87)90001-5] [Citation(s) in RCA: 127] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Simple (one-dimensional) climate models suggest that carbon dioxide concentrations during the Archean must have been at least 100-1000 times the present level to keep the Earth's surface temperature above freezing in the face of decreased solar luminosity. Such models provide only lower bounds on CO2, so it is possible that CO2 levels were substantially higher than this and that the Archean climate was much warmer than today. Periods of extensive glaciation during the early and late Proterozoic, on the other hand, indicate that the climate at these times was relatively cool. To be consistent with climate models CO2 partial pressures must have declined from approximately 0.03 to 0.3 bar around 2.5 Ga ago to between 10(-3) and 10(-2) bar at 0.8 Ga ago. This steep decrease in carbon dioxide concentrations may be inconsistent with paleosol data, which implies that pCO2 did not change appreciably during that time. Oxygen was essentially absent from the Earth's atmosphere and oceans prior to the emergence of a photosynthetic source, probably during the late Archean. During the early Proterozoic the atmosphere and surface ocean were apparently oxidizing, while the deep ocean remained reducing. An upper limit of 6 x 10(-3) bar for pO2 at this time can be derived by balancing the burial rate of organic carbon with the rate of oxidation of ferrous iron in the deep ocean. The establishment of oxidizing conditions in the deep ocean, marked by the disappearance of banded iron formations approximately 1.7 Ga ago, permitted atmospheric oxygen to climb to its present level. O2 concentrations may have remained substantially lower than today, however, until well into the Phanerozoic.
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Affiliation(s)
- J F Kasting
- NASA Ames Research Center, Moffett Field, CA 94035, USA
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Abstract
Tentative geochemical cycles for the pre-biologic Earth are developed by comparing the relative fluxes of oxygen, dissolved iron, and sulfide to the atmosphere and ocean. The flux of iron is found to exceed both the oxygen and the sulfide fluxes. Because of the insolubility of iron oxides and sulfides the implication is that dissolved iron was fairly abundant and that oxygen and sulfide were rare in the atmosphere and ocean. Sulfate, produced by the oxidation of volcanogenic sulfur gases, was the most abundant sulfur species in the ocean, but its concentration was low by modern standards because of the absence of the river-borne flux of dissolved sulfate produced by oxidative weathering of the continents. These findings are consistent with the geologic record of the isotopic composition of sedimentary sulfates and sulfides. Except in restricted environments, the sulfur metabolism of the earliest organisms probably involved oxidized sulfur species not sulfide.
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Affiliation(s)
- J C Walker
- Department of Atmospheric and Oceanic Science, The University of Michigan, Ann Arbor 48109, USA
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Kasting JF, Pollack JB. Effects of high CO2 levels on surface temperature and atmospheric oxidation state of the early Earth. JOURNAL OF ATMOSPHERIC CHEMISTRY 1984; 1:403-428. [PMID: 11541984 DOI: 10.1007/bf00053803] [Citation(s) in RCA: 88] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
One-dimensional radiative-convective and photochemical models are used to examine the effects of enhanced CO2 concentrations on the surface temperature of the early Earth and the composition of the prebiotic atmosphere. Carbon dioxide concentrations of the order of 100-1000 times the present level are required to compensate for an expected solar luminosity decrease of 25-30%, if CO2 and H2O were the only greenhouse gases present. The primitive stratosphere was cold and dry, with a maximum H2O volume mixing ratio of 10(-6). The atmospheric oxidation state was controlled by the balance between volcanic emission of reduced gases, photo-stimulated oxidation of dissolved Fe+2 in the oceans, escape of hydrogen to space, and rainout of H2O2 and H2CO. At high CO2 levels, production of hydrogen owing to rainout of H2O2 would have kept the H2 mixing ratio above 2x10(-4) and the ground-level O2 mixing ratio below 10(-11), even if no other sources of hydrogen were present. Increased solar UV fluxes could have led to small changes in the ground-level mixing ratios of both O2 and H2.
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Affiliation(s)
- J F Kasting
- NASA Ames Research Center, Moffett Field, CA 94035, USA
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McLennan SM, Taylor SR. Continental freeboard, sedimentation rates and growth of continental crust. Nature 1983. [DOI: 10.1038/306169a0] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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