Redox conditions and nitrogen cycling during the Triassic-Jurassic transition: A new perspective from the mid-Panthalassa

Fujisaki, Wataru; Fukami, Yusuke; Matsui, Yohei; Sato, Tadasu; Sawaki, Yusuke; Suzuki, Katsuhiko

doi:10.1016/j.earscirev.2020.103173

Cited by 14 publications

(9 citation statements)

References 88 publications

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“…The Triassic–Jurassic boundary (−2.2 m) in the Katsuyama section was located based on the transition from the Globolaxtorum tozeri radiolarian Zone to the Pantanellium tanuense Zone 59 . This placement is supported by the LAD of the conodont Misikella posthernsteini 59 , 62 and coincides with a noticeable change in the color of the chert 40 , 66 . The overlying Lower Jurassic beds (−2.2 m to 2.4 m) are assigned to the Parahsuum tanuense Zone 67 , 68 and exhibit a noticeable transition from predominantly red to predominantly gray cherts in the middle of Subzone III, indicating a Hettangian to Sinemurian (Early Jurassic) age for the change in environmental conditions 40 , 66 .…”

Section: Methodssupporting

confidence: 53%

“…Photic-zone euxinia is unlikely due to low concentrations of TS (Fig. 2c ) and redox-sensitive trace elements 40 in the study section, and, thus, this process cannot account for the negative Δ 199 Hg values 41 . Furthermore, an insignificant correlation between Δ 199 Hg and TS also indicates limited influence by euxinia in both the photic zone and deeper water column (Supplementary Fig.…”

Section: Discussionmentioning

confidence: 94%

“…The gray field represents the mercury-enriched interval (MEI), the vertical rectangle in e is volcanic Δ 199 Hg values (+0.02 ± 0.06‰ 71 ), and the vertical rectangle in f is Δ 200 Hg values of 0 ± 0.05‰ 71 . Biozonation from references 40 , 59 . Horizontal bars in the Δ 199 Hg and Δ 200 Hg profiles are standard deviation (2σ) values.…”

Section: Resultsmentioning

confidence: 99%

“…The lowermost beds of our measured section are ~3 meters (−5.1 m to −2.2 m) below the T–J boundary and are likely Rhaetian (latest Triassic) in age, based on the occurrence of the Haeckelicyrtium breviora and Globolaxtorum tozeri radiolarian assemblages as well as the Misikella posthernsteini conodont Zone 40 . The Triassic–Jurassic boundary (−2.2 m) in the Katsuyama section was located based on the transition from the Globolaxtorum tozeri radiolarian Zone to the Pantanellium tanuense Zone 59 .…”

Section: Methodsmentioning

confidence: 92%

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Mercury evidence for combustion of organic-rich sediments during the end-Triassic crisis

et al. 2022

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The sources of isotopically light carbon released during the end-Triassic mass extinction remain in debate. Here, we use mercury (Hg) concentrations and isotopes from a pelagic Triassic–Jurassic boundary section (Katsuyama, Japan) to track changes in Hg cycling. Because of its location in the central Panthalassa, far from terrigenous runoff, Hg enrichments at Katsuyama record atmospheric Hg deposition. These enrichments are characterized by negative mass independent fractionation (MIF) of odd Hg isotopes, providing evidence of their derivation from terrestrial organic-rich sediments (Δ199Hg < 0‰) rather than from deep-Earth volcanic gases (Δ199Hg ~ 0‰). Our data thus provide evidence that combustion of sedimentary organic matter by igneous intrusions and/or wildfires played a significant role in the environmental perturbations accompanying the event. This process has a modern analog in anthropogenic combustion of fossil fuels from crustal reservoirs.

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Section: Methodssupporting

confidence: 53%

Section: Discussionmentioning

confidence: 94%

Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 92%

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Mercury evidence for combustion of organic-rich sediments during the end-Triassic crisis

et al. 2022

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“…2001, Fujisaki et al . 2020). These interpretations largely depend on the assumption that the TN, TC and TOC contents, as well as δ 15 N TN and δ 13 C org values, can be accurately determined.…”

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confidence: 99%

Pre‐treatment Methods for Accurate Determination of Total Nitrogen and Organic Carbon Contents and their Stable Isotopic Compositions: Re‐evaluation from Geological Reference Materials

Fujisaki

Matsui

Ueda

et al. 2021

Geostandard Geoanalytic Res

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This study reports total nitrogen (TN), carbon (TC) and organic carbon (TOC) contents, as well as stable isotopic ratios (δ15NTN, δ13CTC and δ13Corg), from marine, stream and lacustrine geological reference materials (JMs‐1, JMs‐2, SBC‐1, SCo‐2, JSd‐3, JSd‐4 and JLk‐1), which can be classified into two types; modern surface, and ancient, sediments. Using this newly obtained data set, we systematically investigated the biases of three pre‐treatment methods for nitrogen and carbon measurements: (1) non‐acidification (untreated method), (2) HCl acidification in various conditions and subsequent rinsing with high‐purity water repeatedly (rinse method) and (3) in situ acidification in a gold‐coated silver capsule (capsule method). Our results showed that such acid pre‐treatments can affect both nitrogen and carbon measurements, except for the carbon data of the ancient geological RMs. Therefore, the nitrogen analysis should be conducted using untreated samples while carbon data should be obtained using the capsule method for modern surface sediments and the rinse method (6 mol l‐1 HCl acidification at 70 °C) for ancient sediments. We believe that using appropriate pre‐treatment methods is crucial to deriving new interpretations of ancient/modern environmental processes and mechanisms in the future.

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Onset of environmental disturbances in the Panthalassic Ocean over one million years prior to the Triassic-Jurassic boundary mass extinction

Schoepfer

Shen

Sano

et al. 2022

Earth-Science Reviews

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Redox conditions and nitrogen cycling during the Triassic-Jurassic transition: A new perspective from the mid-Panthalassa

Cited by 14 publications

References 88 publications

Mercury evidence for combustion of organic-rich sediments during the end-Triassic crisis

Mercury evidence for combustion of organic-rich sediments during the end-Triassic crisis

Pre‐treatment Methods for Accurate Determination of Total Nitrogen and Organic Carbon Contents and their Stable Isotopic Compositions: Re‐evaluation from Geological Reference Materials

Onset of environmental disturbances in the Panthalassic Ocean over one million years prior to the Triassic-Jurassic boundary mass extinction

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