A prolonged, two-step oxygenation of Earth’s early atmosphere: Support from confidence intervals

Geology ◽

10.1130/g49385.1 ◽

2021 ◽

Author(s):

Malcolm S.W. Hodgskiss ◽

Erik A. Sperling

Keyword(s):

Confidence Intervals ◽

Sulfur Isotopes ◽

Red Beds ◽

Great Oxidation Event ◽

Early Atmosphere ◽

Mass Independent Fractionation ◽

Carbon Isotope Excursion ◽

Loss Of Mass ◽

Geologic Record ◽

Atmospheric Level

The Great Oxidation Event (GOE), among Earth’s most transformative events, marked the sustained presence of oxygen above 10–5 times the present atmospheric level. Estimates of the onset of the GOE span 2501–2225 Ma and are based primarily on the loss of mass-independent fractionation of sulfur isotopes (MIF-S) in pyrite. To better constrain the timing of the GOE, we apply probabilistic techniques to estimate the confidence intervals of four proxies: MIF-S, redox-sensitive detrital minerals, "red beds," and I/(Ca + Mg). These GOE proxies are drawn from a highly fragmentary geologic record, and consequently, estimates of the 95% confidence intervals span tens to hundreds of millions of years—orders of magnitude larger than suggested by radiometric constraints on individual successions. Confidence interval results suggest that red beds and nonzero I/(Ca + Mg) values may have appeared earlier than 2480 Ma and 2460 Ma, respectively, whereas redox-sensitive detrital minerals and MIF-S may have disappeared after 2210 Ma and 2190 Ma, respectively. These data suggest a delay of potentially >300 m.y. between initial and permanent oxygenation of the atmosphere and a delay of tens of millions of years between onset of the Lomagundi-Jatuli carbon isotope excursion and permanent oxygenation of the atmosphere.

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Coupling of the atmosphere and sediment melts across the Archean-Proterozoic transition

10.21203/rs.3.rs-55162/v1 ◽

2020 ◽

Author(s):

Janne Liebmann ◽

Christopher Spencer ◽

Christopher Kirkland ◽

Claire Bucholz ◽

Xiao-Ping Xia ◽

...

Keyword(s):

Oxygen Isotope ◽

Isotope Ratio ◽

Sulfur Isotopes ◽

Isotope Ratios ◽

Causal Link ◽

Oxygen Isotope Ratios ◽

Mass Independent Fractionation ◽

The Earth ◽

Geologic Record ◽

Atmospheric Changes

Abstract The Archean-Proterozoic transition marks a time of fundamental geologic, biologic, and atmospheric changes to the Earth system, including oxygenation of the atmosphere (termed the Great Oxygenation Event; GOE), and the emergence of continents above sea-level. The impacts of the GOE on Earth’s surface environment are imprinted on the geologic record, including the attenuation of mass-independent fractionation of sulfur isotopes (S-MIF). Temporally overlapping geologic and geochemical observations (e.g. a change in oxygen isotope ratio of sediment melts) imply the widespread subaerial emergence of continents was coeval with atmospheric oxygenation. Here we present triple sulfur isotope ratios in pyrite and oxygen isotope ratios in garnet and zircon in a global suite of Archean and Proterozoic sediment-derived granitoids. These crustal melts record an increase in average 18O/16O isotope ratio and a disappearance of S-MIF in the Paleoproterozoic. The coupled behaviour of sulfur and oxygen isotope signatures imply a potential causal link between the emergence of continents and atmospheric oxygenation at ~2.3 Ga.

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Mercury abundance and isotopic composition indicate subaerial volcanism prior to the end-Archean “whiff” of oxygen

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.2107511118 ◽

2021 ◽

Vol 118 (33) ◽

pp. e2107511118

Author(s):

Jana Meixnerová ◽

Joel D. Blum ◽

Marcus W. Johnson ◽

Eva E. Stüeken ◽

Michael A. Kipp ◽

...

Keyword(s):

Isotope Composition ◽

Volcanic Rocks ◽

Nutrient Supply ◽

Photochemical Reactions ◽

Biological Productivity ◽

Stable Isotope Composition ◽

Great Oxidation Event ◽

Early Atmosphere ◽

Driving Mechanisms ◽

Pilbara Craton

Earth’s early atmosphere witnessed multiple transient episodes of oxygenation before the Great Oxidation Event 2.4 billion years ago (Ga) [e.g., A. D. Anbar et al., Science 317, 1903–1906 (2007); M. C. Koehler, R. Buick, M. E. Barley, Precambrian Res. 320, 281–290 (2019)], but the triggers for these short-lived events are so far unknown. Here, we use mercury (Hg) abundance and stable isotope composition to investigate atmospheric evolution and its driving mechanisms across the well-studied “whiff” of O2 recorded in the ∼2.5-Ga Mt. McRae Shale from the Pilbara Craton in Western Australia [A. D. Anbar et al., Science 317, 1903–1906 (2007)]. Our data from the oxygenated interval show strong Hg enrichment paired with slightly negative ∆199Hg and near-zero ∆200Hg, suggestive of increased oxidative weathering. In contrast, slightly older beds, which were evidently deposited under an anoxic atmosphere in ferruginous waters [C. T. Reinhard, R. Raiswell, C. Scott, A. D. Anbar, T. W. Lyons, Science 326, 713–716 (2009)], show Hg enrichment coupled with positive ∆199Hg and slightly negative ∆200Hg values. This pattern is consistent with photochemical reactions associated with subaerial volcanism under intense UV radiation. Our results therefore suggest that the whiff of O2 was preceded by subaerial volcanism. The transient interval of O2 accumulation may thus have been triggered by diminished volcanic O2 sinks, followed by enhanced nutrient supply to the ocean from weathering of volcanic rocks causing increased biological productivity.

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A 1.25 Ga depositional age for the “Paleoproterozoic” Mapedi red beds, Kalahari manganese field, South Africa: New constraints on the timing of oxidative weathering and hematite mineralization

Geology ◽

10.1130/g46707.1 ◽

2019 ◽

Vol 48 (1) ◽

pp. 44-48 ◽

Cited By ~ 2

Author(s):

Birger Rasmussen ◽

Janet R. Muhling ◽

Jian-Wei Zi ◽

Harilaos Tsikos ◽

Woodward W. Fischer

Keyword(s):

South Africa ◽

Climatic Conditions ◽

Red Beds ◽

The West ◽

Zircon Age ◽

Great Oxidation Event ◽

Depositional Age ◽

Red Bed

Abstract The Great Oxidation Event (GOE) is marked by the loss of readily oxidizable detrital minerals and the onset of oxidative weathering. One of the oldest post-GOE weathering surfaces, which extends for almost 350 km along strike, occurs in Griqualand West, South Africa. It is best preserved east of the Blackridge thrust, where oxidized paleoweathering profiles are developed below the unconformity at the base of Mapedi-Gamagara red beds. In the Maremane Dome, the red beds preserve pisolitic hematite laterites, which indicate a highly oxygenated atmosphere and suggest hot and humid climatic conditions. The Mapedi and Gamagara Formations are undated east of the Blackridge thrust but were thought to be lithological correlatives of the ≥1.91 Ga Mapedi red bed sequence to the west. Here, we report a U-Pb zircon age of 1.25 Ga for a felsic tuff in red beds of the Mapedi Formation in the Kalahari manganese field. The new tuff age shows that the Mapedi red beds east of the thrust were deposited >650 m.y. after the Mapedi Formation to the west, and therefore they are part of a distinct Mesoproterozoic sequence. Based on lithologic and sedimentological similarities, the Mapedi-east and Gamagara formations are likely to be correlatives that were deposited on an ancient weathering surface at ca. 1.25 Ga. Our findings suggest that key evidence for a highly oxygenated atmosphere during the early Paleoproterozoic actually formed at ca. 1.25 Ga during a major episode of Mesoproterozoic oxidative weathering.

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Timing and tempo of the Great Oxidation Event

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1608824114 ◽

2017 ◽

Vol 114 (8) ◽

pp. 1811-1816 ◽

Cited By ~ 164

Author(s):

Ashley P. Gumsley ◽

Kevin R. Chamberlain ◽

Wouter Bleeker ◽

Ulf Söderlund ◽

Michiel O. de Kock ◽

...

Keyword(s):

Atmospheric Oxygen ◽

Kaapvaal Craton ◽

Large Igneous Province ◽

Snowball Earth ◽

Low Latitude ◽

Great Oxidation Event ◽

Carbon Isotope Excursion ◽

Igneous Province ◽

Age Constraints ◽

Exact Timing

The first significant buildup in atmospheric oxygen, the Great Oxidation Event (GOE), began in the early Paleoproterozoic in association with global glaciations and continued until the end of the Lomagundi carbon isotope excursion ca. 2,060 Ma. The exact timing of and relationships among these events are debated because of poor age constraints and contradictory stratigraphic correlations. Here, we show that the first Paleoproterozoic global glaciation and the onset of the GOE occurred between ca. 2,460 and 2,426 Ma, ∼100 My earlier than previously estimated, based on an age of 2,426 ± 3 Ma for Ongeluk Formation magmatism from the Kaapvaal Craton of southern Africa. This age helps define a key paleomagnetic pole that positions the Kaapvaal Craton at equatorial latitudes of 11° ± 6° at this time. Furthermore, the rise of atmospheric oxygen was not monotonic, but was instead characterized by oscillations, which together with climatic instabilities may have continued over the next ∼200 My until ≤2,250–2,240 Ma. Ongeluk Formation volcanism at ca. 2,426 Ma was part of a large igneous province (LIP) and represents a waning stage in the emplacement of several temporally discrete LIPs across a large low-latitude continental landmass. These LIPs played critical, albeit complex, roles in the rise of oxygen and in both initiating and terminating global glaciations. This series of events invites comparison with the Neoproterozoic oxygen increase and Sturtian Snowball Earth glaciation, which accompanied emplacement of LIPs across supercontinent Rodinia, also positioned at low latitude.

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Supplemental Material: A prolonged, two-step oxygenation of Earth’s early atmosphere: Support from confidence intervals

10.1130/geol.s.16725484 ◽

2021 ◽

Author(s):

Malcolm S.W. Hodgskiss ◽

Erik A. Sperling

Keyword(s):

Confidence Intervals ◽

Geochemical Data ◽

Early Atmosphere

Details of the equations used, and compiled geological/geochemical data.<br>

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Simultaneous fractionation of sulfur dioxide explains mass independent fractionation of sulfur isotopes in Archean sedimentary pyrites

Chemical Geology ◽

10.1016/j.chemgeo.2021.120640 ◽

2021 ◽

pp. 120640

Author(s):

M. Chen ◽

Z. Huang ◽

I.H. Campbell ◽

M. Sambridge ◽

J.N. Ávila

Keyword(s):

Sulfur Dioxide ◽

Sulfur Isotopes ◽

Mass Independent Fractionation

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The Great Oxidation

10.23943/princeton/9780691145020.003.0008 ◽

2017 ◽

Cited By ~ 1

Author(s):

Donald Eugene Canfield

Keyword(s):

Oxygen Content ◽

Atmospheric Chemistry ◽

Tipping Point ◽

Earth’S Atmosphere ◽

Great Oxidation Event ◽

Earth's Atmosphere ◽

Geologic Record

This chapter deals with the “great oxidation event” (GOE), which represents a quantum shift in the oxygen content of the atmosphere. It suggests that the GOE represents the evolution of cyanobacteria. According to the geologic record, the oxygen content of Earth's atmosphere increased dramatically around 2.3 billion years ago. Since cyanobacteria likely evolved much earlier, it does not appear that a well-oxygenated atmosphere is a necessary or immediate consequence of the activities of oxygen-producing organisms. Atmospheric chemistry is a slave to the dynamics of the mantle, as the interior and exterior of the planet are connected in a profound way. Indeed, it took half of Earth's history for the mantle to quiet to point where oxygen could accumulate. This, however, represented a watershed, a tipping point if you will, where the chemistry of Earth's surface was forever altered.

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