Evidence for episodic oxygenation in a weakly redox-buffered deep mid-Proterozoic ocean

Planavsky, Noah J.; Slack, John F.; Cannon, William F.; O’Connell, Brennan; Isson, Terry T.; Asael, Dan; Jackson, J. C.; Hardisty, Dalton S.; Lyons, Timothy W.; Bekker, Andrey

doi:10.1016/j.chemgeo.2018.03.028

Cited by 74 publications

(46 citation statements)

References 82 publications

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“…Iron speciation results for much of the Nonesuch Formation sediments indicate a high degree of pyritization with oxic deposition (Figure ), which is rare for modern systems (Tables S2 and S3). However, especially with limited oxygen availability in the mid‐Proterozoic (e.g., Planavsky et al, ), reduced chemical species such as pyrite are to be expected when oxygen is consumed. In contrast, MIS does not display a high degree of pyritization, likely attributed to a sulfide limitation in porewater (which fluctuates between 0–7 mM H 2 S; Kisman‐Costello et al, ).…”

Section: Resultsmentioning

confidence: 99%

Redox Chemistry and Molybdenum Burial in a Mesoproterozoic Lake

Rico

Sheldon

Gallagher

et al. 2019

Geophysical Research Letters

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While marine sediments have been used to constrain a history of redox chemistry throughout the Precambrian, far fewer data have been generated from lakes. With major biological innovations thought to have occurred in Proterozoic lakes, understanding their chemistry is critical for understanding the evolution of eukaryotic life. We use sediment geochemistry to characterize the redox conditions of the Nonesuch Formation (~1.1 Ga) and a modern analogue for the Proterozoic: the Middle Island Sinkhole in Lake Huron (USA). Iron speciation, Mo contents, and Mo‐U covariation demonstrate oxic and anoxic—not euxinic—environments, with no clear indicators of enhanced biological productivity in the Nonesuch Formation. Moderate Mo enrichments observed in the Nonesuch Formation are not attributed to euxinia, but instead to an authigenic particulate shuttle. We suggest that the Fe and Mo sediment geochemistry of these lacustrine systems reflect only local water column and sediment burial conditions and not atmospheric oxygenation.

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Section: Resultsmentioning

confidence: 99%

Redox Chemistry and Molybdenum Burial in a Mesoproterozoic Lake

Rico

Sheldon

Gallagher

et al. 2019

Geophysical Research Letters

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“…For example, the “Canfield ocean” featured anoxic and euxinic (sulfide‐rich) deep‐ocean conditions through the Proterozoic, relieved only by a relatively unidirectional rise in oxygen during the late Ediacaran (Canfield, ). Broader stratigraphic and geographic coverage, including onshore–offshore transects, as well as new redox proxies have provided a more nuanced view of Proterozoic redox with much less stability (Diamond & Lyons, ; Doyle, Poulton, Newton, Podkovyrov, & Bekker, ; He et al, ; Li, Cheng, et al, ; Li, Zhang, et al, ; Planavsky, Cole, et al, ; Planavsky, Slack, et al, ; Sperling et al, ; Tang, Shi, Wang, & Jiang, ). Any attempts to model Proterozoic redox conditions are similarly left with the conclusion that the marine redox landscape was patchy and complicated (Reinhard, Planavsky, Olson, Lyons, & Erwin, ).…”

Section: Myths About Oxygen and The Rise Of Animalsmentioning

confidence: 99%

“…The defining characteristic of the Proterozoic ocean rather appears to be the lack of a strong redox buffer (Planavsky, Cole, et al, ; Planavsky, Slack, et al, ), in stark contrast to the strongly ferruginous (anoxic and iron‐rich) Archean oceans and the largely oxic modern oceans. Although Proterozoic oceans were dominantly reducing, conditions varied spatially and temporally—there were almost certainly regions that were ferruginous, euxinic, and oxic throughout the Eon.…”

Section: Myths About Oxygen and The Rise Of Animalsmentioning

confidence: 99%

On the co‐evolution of surface oxygen levels and animals

et al. 2020

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Few topics in geobiology have been as extensively debated as the role of Earth's oxygenation in controlling when and why animals emerged and diversified. All currently described animals require oxygen for at least a portion of their life cycle. Therefore, the transition to an oxygenated planet was a prerequisite for the emergence of animals. Yet, our understanding of Earth's oxygenation and the environmental requirements of animal habitability and ecological success is currently limited; estimates for the timing of the appearance of environments sufficiently oxygenated to support ecologically stable populations of animals span a wide range, from billions of years to only a few million years before animals appear in the fossil record. In this light, the extent to which oxygen played an important role in controlling when animals appeared remains a topic of debate. When animals originated and when they diversified are separate questions, meaning either one or both of these phenomena could have been decoupled from oxygenation. Here, we present views from across this interpretive spectrum—in a point–counterpoint format—regarding crucial aspects of the potential links between animals and surface oxygen levels. We highlight areas where the standard discourse on this topic requires a change of course and note that several traditional arguments in this “life versus environment” debate are poorly founded. We also identify a clear need for basic research across a range of fields to disentangle the relationships between oxygen availability and emergence and diversification of animal life.

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“…Siderite forms under certain unusual environmental conditions, often linked to changes in pH, changes in p CO 2 , or changes in microbial metabolism (Dong, ; Konhauser, Newman, & Kappler, ; Van Lith, Warthmann, Vasconcelos, & McKenzie, ; Sanchez‐Roman et al, ; Sanchez‐Roman, Puente‐Sanchez, Parro, & Amils, ; Xiouzhu, Unfei, & Huaiyan, ). In particular, the presence of siderite in the geological record has been used as an environmental indicator for conditions at Earth's surface (e.g., levels of atmospheric pCO 2 and O 2 , redox conditions, and iron cycling) at various points in Earth history, especially during the Archean Eon and Proterozoic Eon (Bachan & Kump, ; Canfield et al, ; Halevy, Alesker, Schuster, Popovitz‐Biro, & Feldman, ; Holland, ; Konhauser et al, ; Ohmoto, Watanabe, & Kumazawa, ; Planavsky et al, ).…”

Section: Introductionmentioning

confidence: 99%

“…Earth history, especially during the Archean Eon and Proterozoic Eon (Bachan & Kump, 2015;Canfield et al, 2018;Halevy, Alesker, Schuster, Popovitz-Biro, & Feldman, 2017;Holland, 2006;Konhauser et al, 2017;Ohmoto, Watanabe, & Kumazawa, 2004;Planavsky et al, 2018).…”

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confidence: 99%

The microbially driven formation of siderite in salt marsh sediments

et al. 2019

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We employ complementary field and laboratory‐based incubation techniques to explore the geochemical environment where siderite concretions are actively forming and growing, including solid‐phase analysis of the sediment, concretion, and associated pore fluid chemistry. These recently formed siderite concretions allow us to explore the geochemical processes that lead to the formation of this less common carbonate mineral. We conclude that there are two phases of siderite concretion growth within the sediment, as there are distinct changes in the carbon isotopic composition and mineralogy across the concretions. Incubated sediment samples allow us to explore the stability of siderite over a range of geochemical conditions. Our incubation results suggest that the formation of siderite can be very rapid (about two weeks or within 400 hr) when there is a substantial source of iron, either from microbial iron reduction or from steel material; however, a source of dissolved iron is not enough to induce siderite precipitation. We suggest that sufficient alkalinity is the limiting factor for siderite precipitation during microbial iron reduction while the lack of dissolved iron is the limiting factor for siderite formation if microbial sulfate reduction is the dominant microbial metabolism. We show that siderite can form via heated transformation (at temperature 100°C for 48 hr) of calcite and monohydrocalcite seeds in the presence of dissolved iron. Our transformation experiments suggest that the formation of siderite is promoted when carbonate seeds are present.

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Evidence for episodic oxygenation in a weakly redox-buffered deep mid-Proterozoic ocean

Cited by 74 publications

References 82 publications

Redox Chemistry and Molybdenum Burial in a Mesoproterozoic Lake

Redox Chemistry and Molybdenum Burial in a Mesoproterozoic Lake

On the co‐evolution of surface oxygen levels and animals

The microbially driven formation of siderite in salt marsh sediments

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