A lower limit for atmospheric carbon dioxide levels 3.2 billion years ago

Hessler, Angela M.; Lowe, Donald R.; Jones, Robin L.; Bird, Dennis K.

doi:10.1038/nature02471

Cited by 133 publications

(85 citation statements)

References 26 publications

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“…Oxygen isotope compositions of ISB serpentines suggest that they formed in the presence of seawater with a δ 18 O similar to modern oceans, consistent with oxygen isotope studies of Archaean biogenic phosphates (4), volcanic rocks from other Archaean greenstone Belts (13,43), and mafic pillow lavas and sheeted dikes in the ISB (14). We therefore suggest that the low δ 18 O of Archaean chemical sediments is a result of postdepositional exchange with shallow ground-or pore waters.…”

Section: Discussionsupporting

confidence: 57%

“…For an atmospheric mixing ratio of CH 4 in the Archaean of approximately 64 to 480 ppmv, the pCO 2 needed to maintain a haze-free atmosphere would be between 10 −4.2 and 10 −2.6 bar, or at a minimum approximately 0.2 to 6 times present atmospheric levels. These values are in the pCH 4 and pCO 2 ranges suggested by Precambrian paleosols, methanogenic metabolic constraints, and magnetite/siderite stability in early Archaean banded iron formations (9,43,44) (Fig. S7).…”

Section: Models For a Global Hydrogen Budgetmentioning

confidence: 99%

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Isotope composition and volume of Earth’s early oceans

Pope

Bird

Rosing

2012

Proc. Natl. Acad. Sci. U.S.A.

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132

145

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Oxygen and hydrogen isotope compositions of Earth's seawater are controlled by volatile fluxes among mantle, lithospheric (oceanic and continental crust), and atmospheric reservoirs. Throughout geologic time the oxygen mass budget was likely conserved within these Earth system reservoirs, but hydrogen's was not, as it can escape to space. Isotopic properties of serpentine from the approximately 3.8 Ga Isua Supracrustal Belt in West Greenland are used to characterize hydrogen and oxygen isotope compositions of ancient seawater. Archaean oceans were depleted in deuterium [expressed as δD relative to Vienna standard mean ocean water (VSMOW)] by at most 25 AE 5‰, but oxygen isotope ratios were comparable to modern oceans. Mass balance of the global hydrogen budget constrains the contribution of continental growth and planetary hydrogen loss to the secular evolution of hydrogen isotope ratios in Earth's oceans. Our calculations predict that the oceans of early Earth were up to 26% more voluminous, and atmospheric CH 4 and CO 2 concentrations determined from limits on hydrogen escape to space are consistent with clement conditions on Archaean Earth. Both interpretations have been questioned based on the susceptibility of chemical sediments to diagenetic alteration over geologic time (2, 4), and for the latter, a lack of geologic evidence for the extreme greenhouse gas concentrations required to sustain such high temperatures under a less luminous young Sun (9).Minerals formed by metasomatic reactions between seawater and oceanic lithosphere provide an alternative proxy for early ocean chemistry (10-14). Here we report hydrogen and oxygen isotope compositions of 114 silicate mineral separates from the ca. 3.8 Ga Isua Supracrustal Belt (ISB) of West Greenland, including metamorphosed basalts, gabbros, and ultramafic rocks that represent fragments of Eoarchaean oceanic crust (see Fig. S1, Table S2). Minerals formed during heterogeneous late-stage CO 2 -or meteoric-dominated metamorphic overprinting are distinguished by characteristic trends in their coupled δD and δ 18 O values (Fig. S2). In contrast, serpentine minerals formed by reaction of seawater with ultramafic rocks (peridotites) preserved in a low-strain enclave of the ISB (15) define a different isotopic trend. Here we use these serpentines to constrain D∕H and 18 O∕ 16 O ratios of the Eoarchaean ocean. Serpentine Isotope GeochemistrySerpentine-group minerals are hydrous magnesian silicates commonly formed by hydrothermal infiltration of seawater into ultramafic oceanic crust, hydration of the mantle wedge by slabderived fluids, or fluid-rock interaction in continentally emplaced ultramafic lithologies (16)(17)(18). Serpentinized oceanic peridotites are dominantly composed of low-temperature (<300°C) polymorphs lizardite and chrysotile, and to a lesser extent antigorite, which forms at temperatures >250°C (17). In modern oceanic serpentinites, antigorites have δD between −46 and −30‰ (Figs. 1 and 2A, filled squares), values that indicate equilibrium with modern-...

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Section: Discussionsupporting

confidence: 57%

Section: Models For a Global Hydrogen Budgetmentioning

confidence: 99%

Isotope composition and volume of Earth’s early oceans

Pope

Bird

Rosing

2012

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

132

145

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“…Methane is a very efficient greenhouse gas, and levels higher than 100 PAL would potentially have been enough to warm the surface above 08C (Pavlov et al, 2000), which implies that climate is no longer regulated by the carbonate-silicate cycle. The level of CO 2 could potentially have been extremely low if methane became the main greenhouse gas, and this seems to be confirmed by the studies of paleosols from the Late Archean and Neoproterozoic, in which no trace of carbonates were found (Rye et al, 1995;Hessler et al, 2004). Note that this does not take the effect of hazes into account.…”

Section: A Rise In Methane?supporting

confidence: 53%

Origin and Evolution of Life on Terrestrial Planets

Brack

Horneck²,

Cockell

et al. 2010

Astrobiology

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After Earth's origin, our host star, the Sun, was shining 20-25% less brightly than today. Without greenhouselike conditions to warm the atmosphere, our early planet would have been an ice ball, and life may never have evolved. But life did evolve, which indicates that greenhouse gases must have been present on early Earth to warm the planet. Evidence from the geological record indicates an abundance of the greenhouse gas CO 2 . CH 4 was probably present as well; and, in this regard, methanogenic bacteria, which belong to a diverse group of anaerobic prokaryotes that ferment CO 2 plus H 2 to CH 4 , may have contributed to modification of the early atmosphere. Molecular oxygen was not present, as is indicated by the study of rocks from that era, which contain iron carbonate rather than iron oxide. Multicellular organisms originated as cells within colonies that became increasingly specialized. The development of photosynthesis allowed the Sun's energy to be harvested directly by life-forms. The resultant oxygen accumulated in the atmosphere and formed the ozone layer in the upper atmosphere. Aided by the absorption of harmful UV radiation in the ozone layer, life colonized Earth's surface. Our own planet is a very good example of how life-forms modified the atmosphere over the planets' lifetime. We show that these facts have to be taken into account when we discover and characterize atmospheres of Earth-like exoplanets. If life has originated and evolved on a planet, then it should be expected that a strong co-evolution occurred between life and the atmosphere, the result of which is the planet's climate.

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“…The sulphate, then allowed sulphate-reducing bacteria to generate dissolved sulphide in quantities sufficient to remove all the available iron from the oceans and form pyrite, FeS 2 (Vargas et al, 1998). Geochemical modelling reacting basalt with chemical composition of rainwater as the present day, but with initial values of log f O2 = -70 and log f CO2 = -1.5 (Hessler et al, 2004) and containing the volcanic gases H 2 , H 2 S, SO 2 , CO 2 and CO (Zolotov and Shock, 2000;Catling and Claire, 2005), produced weathering minerals that include pyrite (FeS 2 ), kaolinite (Al 2 Si 2 O 5 (OH) 4 ), chalcedony (SiO 2 ), siderite (FeCO 3 ), calcite (CaCO 3 ) and lizardite (Mg 3 Si 2 O 5 (OH) 4 ). The iron in equilibrium with this mineral assemblage has the value of 10 -3 mol l -1 or 3 ppm (Sverjensky and Lee, 2010).…”

Section: The Big Sixmentioning

confidence: 99%