A Mesoproterozoic iron formation

Canfield, Donald E.; Zhang, Shuichang; Wang, Huajian; Zhao, Wenzhi; Jin, Sheng; Bjerrum, Christian J.; Haxen, Emma R.; Hammarlund, Emma U.

doi:10.1073/pnas.1720529115

Cited by 67 publications

(74 citation statements)

References 89 publications

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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%

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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Section: Introductionmentioning

confidence: 99%

The microbially driven formation of siderite in salt marsh sediments

et al. 2019

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“…New evidence, however, does point to active tectonics during early stages of the Xiamaling Formation deposition. An iron formation (IF) has recently been described as unit 5 (Canfield et al., ; Tang et al., ; Zhang & Zhu, ,) (Figure ), and the sedimentology of this IF is consistent with mass flow events that could have been triggered by tectonic shocks (Canfield et al., ). In addition, the bottom of the IF contains iron‐rich sedimentary rocks that appear to have undergone brittle deformation possibly during mud‐slide events (Canfield et al., ).…”

Section: Methodsmentioning

confidence: 54%

“…An iron formation (IF) has recently been described as unit 5 (Canfield et al., ; Tang et al., ; Zhang & Zhu, ,) (Figure ), and the sedimentology of this IF is consistent with mass flow events that could have been triggered by tectonic shocks (Canfield et al., ). In addition, the bottom of the IF contains iron‐rich sedimentary rocks that appear to have undergone brittle deformation possibly during mud‐slide events (Canfield et al., ). Several bentonite layers have also been discovered within these iron‐rich rocks (Tang et al., ), consistent with active tectonics during deposition of this part of the Xiamaling Formation.…”

Section: Methodsmentioning

confidence: 54%

“…The record has also revealed water‐column conditions ranging between oxygenated, sulfidic, and ferruginous (Diamond, Planavsky, Wang, & Lyons, ; Wang et al., ; Zhang et al., ), with evidence in some parts of the stratigraphy for an oxygen‐minimum zone setting (OMZ) with oxygenated bottom waters (Zhang et al., ). Another part of the succession houses the largest‐known iron formation (IF) in the Mesoproterozoic Era (Canfield et al., ; Zhang & Zhu, ,; Zhu et al., ). Where bottom‐water oxygenation has been identified in the Xiamaling Formation, biogeochemical modeling has revealed that atmospheric oxygen concentrations were likely ≥ 4‐6% of present‐day values (Zhang et al., , ).…”

Section: Introductionmentioning

confidence: 99%

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Paleoenvironmental proxies and what the Xiamaling Formation tells us about the mid‐Proterozoic ocean

et al. 2019

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The Mesoproterozoic Era (1,600–1,000 million years ago, Ma) geochemical record is sparse, but, nevertheless, critical in untangling relationships between the evolution of eukaryotic ecosystems and the evolution of Earth‐surface chemistry. The ca. 1,400 Ma Xiamaling Formation has experienced only very low‐grade thermal maturity and has emerged as a promising geochemical archive informing on the interplay between climate, ecosystem organization, and the chemistry of the atmosphere and oceans. Indeed, the geochemical record of portions of the Xiamaling Formation has been used to place minimum constraints on concentrations of atmospheric oxygen as well as possible influences of climate and climate change on water chemistry and sedimentation dynamics. A recent study has argued, however, that some portions of the Xiamaling Formation deposited in a highly restricted environment with only limited value as a geochemical archive. In this contribution, we fully explore these arguments as well as the underlying assumptions surrounding the use of many proxies used for paleo‐environmental reconstructions. In doing so, we pay particular attention to deep‐water oxygen‐minimum zone environments and show that these generate unique geochemical signals that have been underappreciated. These signals, however, are compatible with the geochemical record of those parts of the Xiamaling Formation interpreted as most restricted. Overall, we conclude that the Xiamaling Formation was most likely open to the global ocean throughout its depositional history. More broadly, we show that proper paleo‐environmental reconstructions require an understanding of the biogeochemical signals generated in all relevant modern analogue depositional environments. We also evaluate new data on the δ98Mo of Xiamaling Formation shales, revealing possible unknown pathways of molybdenum sequestration into sediments and concluding, finally, that seawater at that time likely had a δ98Mo value of about 1.1‰.

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“…The decline of sustained IF deposition after two billion years, beginning~1.7 Ga, may relate to an increase in oceanic sulfate (Kump & Seyfried, 2005), sulfide (Anbar & Knoll, 2002;Canfield, 1998), or environmental oxygen (Holland, 2006;Huston & Logan, 2004;Sleep & Bird, 2008). Although few IFs are known between 1.7 and 1.0 Ga (Figure 3), IF deposition did not completely stop and strata from this period may yet yield more evidence of infrequent but significant iron precipitation, such as the~1.4 Ga Xiamaling IF (Canfield et al, 2018).…”

Section: Sustained Ocean-wide If Depositionmentioning

confidence: 99%

Widespread and Persistent Deposition of Iron Formations for Two Billion Years

Johnson

Molnár

2019

Geophysical Research Letters

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Composed of chemical precipitates rich in iron and silica, Precambrian iron formations from marine sedimentary records may reveal biogeochemical processes over the first half of Earth history. The limited record of early Archean rock suggests that preservation biases the iron formation record. Like ophiolites, which provide a sparse record of past ocean floor, iron formations deposited on oceanic crust ought to also be rare and preserved only when accreted onto cratons. To correct for potential preservation bias, we scaled masses of iron formations to the areal extent of basement rock of similar age and found that the resultant record is consistent with persistent deposition of iron formations across much of the deep ocean for two billion years. Widespread and long‐term iron formations imply that ferrous iron was available in the deep ocean for billions of years and that the requisite (bio)geochemical mechanisms to produce iron formations were present by 3.8 Ga.

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A Mesoproterozoic iron formation

Cited by 67 publications

References 89 publications

The microbially driven formation of siderite in salt marsh sediments

The microbially driven formation of siderite in salt marsh sediments

Paleoenvironmental proxies and what the Xiamaling Formation tells us about the mid‐Proterozoic ocean

Widespread and Persistent Deposition of Iron Formations for Two Billion Years

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