Research ArticleGEOCHEMISTRY

Rapid oxygenation of Earth’s atmosphere 2.33 billion years ago

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Science Advances  13 May 2016:
Vol. 2, no. 5, e1600134
DOI: 10.1126/sciadv.1600134
  • Fig. 1 Geologic sequence in South Africa between 2.5 and 2.2 Ga.

    Stratigraphic correlation of the Rooihoogte and Duitschland Formation between the Carltonville and Duitschland area in the Transvaal Basin, South Africa. Note that the diagram is not drawn according to the real stratal thicknesses. The coarse green wavy line represents the sequence boundary in the middle Rooihoogte/Duitschland Formation that was previously proposed as the time interval in which the GOE occurred (34). Previously, the transition from S-MIF to S-MDF was obscured by an apparent hiatus in the Duitschland Formation. The pink interval represents the GOE identified in this study. The dashed vertical lines in the S-MIF box represent small Δ33S values (<2‰), whereas the solid lines represent the presence of large Δ33S values (>2‰). *From Hannah et al. (40). †From Rasmussen et al. (41).

  • Fig. 2 The δ34S and Δ33S profiles of pyrite in the three cores.

    All isotope data are reported relative to VCDT (Vienna Cañon Diablo Troilite). The dashed lines represent three-point moving averages, whereas the shaded regions represent 1 SEM on the three points. The transitional interval highlighted in pink is defined on the basis of variation of Δ33S records. The stars adjacent to the KEA-4 lithologic column correspond to samples for which thin-section photomicrographs are shown in fig. S2. The Re-Os date of 2316 ± 7 Ma on syngenetic pyrite from the boundary between the Timeball Hill and Rooihoogte formations in the EBA-2 core is from Hannah et al. (40).

  • Fig. 3 Triple sulfur isotope cross-plots of the three intervals of the study sequence.

    (A) δ34S versus δ33S. (B) Δ36S versus Δ33S. The green dashed lines in (A) represent the MDF array. The blue and purple dashed lines in (B) represent the mass-independent and the theoretical mass-dependent fractionation slope, respectively (1, 44). The red dashed lines in both panels represent the regression line of samples in the transitional interval.

  • Fig. 4 Model results showing the increase in pO2 and seawater sulfate level across the GOE.

    The red line represents the atmospheric pO2. The blue solid and dashed lines represent seawater sulfate levels modeled with the pyrite burial flux coupled or decoupled with pO2, respectively.

Supplementary Materials

  • Supplementary material for this article is available at http://advances.sciencemag.org/cgi/content/full/2/5/e1600134/DC1

    Geological background

    Potential of sulfur MIF signals originated from weathering of preexisting S-MIF

    Sensitivity analysis of C-O-S biogeochemical cycling model

    fig. S1. Simplified geological map of the Transvaal Supergroup in the Transvaal and Griqualand West basins, Kaapvaal Craton, South Africa.

    fig. S2. Representative transmitted light photomicrographs showing pyrite (opaque particles) distribution patterns in the samples analyzed in this study.

    fig. S3. Cartoon figure showing the C-S-O geochemical model used in this study.

    fig. S4. Sensitivity analysis for the power coefficient (θ) of pyrite burial and pO2.

    fig. S5. Sensitivity analysis for the coefficient (γ) of weathering of sulfide and pO2.

    table S1. Multiple sulfur isotope composition of the pyrite analyzed in this study. All data are relative to VCDT.

    table S2. Parameters used for the Archean-Proterozoic oxygen-methane-sulfur cycle model.

    References (7581)

  • Supplementary Materials

    This PDF file includes:

    • Geological background
    • Potential of sulfur MIF signals originated from weathering of preexisting S-MIF
    • Sensitivity analysis of C-O-S biogeochemical cycling model
    • fig. S1. Simplified geological map of the Transvaal Supergroup in the Transvaal and Griqualand West basins, Kaapvaal Craton, South Africa.
    • fig. S2. Representative transmitted light photomicrographs showing pyrite (opaque particles) distribution patterns in the samples analyzed in this study.
    • fig. S3. Cartoon figure showing the C-S-O geochemical model used in this study.
    • fig. S4. Sensitivity analysis for the power coefficient (θ) of pyrite burial and pO2.
    • fig. S5. Sensitivity analysis for the coefficient (γ) of weathering of sulfide and pO2.
    • table S1. Multiple sulfur isotope composition of the pyrite analyzed in this study.
    • table S2. Parameters used for the Archean-Proterozoic oxygen-methane-sulfur cycle model.
    • References (75–81)

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