Reply to Pearson and Nicholas, Stassen et al., and Zeebe et al.: Teasing out the missing piece of the PETM puzzle

Wright, James D.; Schaller, Morgan F.

doi:10.1073/pnas.1321876111

Cited by 6 publications

(6 citation statements)

References 15 publications

(19 reference statements)

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“…1.5 × 10 5 years). While consistent with the earliest estimates for the onset duration of the PETM CIE (defined as the time interval between pre-PETM and minimum δ 13 C) [12], subsequent estimates for the onset duration have spanned a much broader range, from instantaneous to greater than 20 kyr [25][26][27][28][29][30][31][32][33][34]. As a result, disagreement over time scale continues to complicate attempts to constrain the source of PETM carbon.…”

Section: Introductionmentioning

confidence: 84%

“…One question is still whether the simplified physics in the cGENIE ocean model (frictional geostrophic, non-eddy resolving circulation) [ 79 ] is sufficient to capture the dynamics of ocean carbon uptake over short time scales. Indeed, this was the criticism suggested by Wright & Schaller [ 32 ], who cited the non-uniform response of surface ocean records to the bomb radiocarbon anomaly, which vary as a function of deep-water influence, as a test case for models. On this basis, the cGENIE model is an effective tool for evaluating the spatial response of ocean carbon uptake.…”

Section: Age-model Independent Methods For Constraining Paleocene–eocmentioning

confidence: 99%

“…Next, sedimentary couplets across the PETM CIE onset in another record from the North Atlantic continental margin were interpreted as seasonal cycles, with the inference that the onset took 13 years. While interpretation of this record remains highly controversial [32][33][34]54,55], the lack of intermediate δ 13 C values in particular has led to descriptions for the CIE onset duration as being over several hundred or thousands of years (a shorter estimate than those provided by cyclostratigraphic methods) [56].…”

Section: History Of Paleocene-eocene Thermal Maximum Onset Duration Estimatesmentioning

confidence: 99%

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Constraints on the onset duration of the Paleocene–Eocene Thermal Maximum

Turner¹

2018

Phil. Trans. R. Soc. A.

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The Paleocene–Eocene Thermal Maximum (PETM, approx. 56 Ma) provides a test case for investigating how the Earth system responds to rapid greenhouse gas-driven warming. However, current rates of carbon emissions are approximately 10 Pg C yr−1, whereas those proposed for the PETM span orders of magnitude—from ≪1 Pg C yr−1 to greater than the anthropogenic rate. Emissions rate estimates for the PETM are hampered by uncertainty over the total mass of PETM carbon released as well as the PETM onset duration. Here, I review constraints on the onset duration of the carbon isotope excursion (CIE) that is characteristic of the event with a focus on carbon cycle model-based attempts that forgo the need for a traditional sedimentary age model. I also review and compare existing PETM carbon input scenarios employing the Earth system model cGENIE and suggest another possibility—that abrupt input of an isotopically depleted carbon source combined with elevated volcanic outgassing over a longer interval can together account for key features of the PETM CIE.This article is part of a discussion meeting issue ‘Hyperthermals: rapid and extreme global warming in our geological past’.

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Section: Introductionmentioning

confidence: 84%

Section: Age-model Independent Methods For Constraining Paleocene–eocmentioning

confidence: 99%

Section: History Of Paleocene-eocene Thermal Maximum Onset Duration Estimatesmentioning

confidence: 99%

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Constraints on the onset duration of the Paleocene–Eocene Thermal Maximum

Turner¹

2018

Phil. Trans. R. Soc. A.

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“…The bedding is also apparent in what few outcrops are available (e.g. see figure 1 in [21]), despite alternative interpretation of the outcrop evidence as the product of jointing [120]. While drilling injection may have occurred, in lieu of a direct geochemical comparison between the injection features and the drilling fluid used, it is not currently possible to verify this other than by inference.…”

Section: (B) Deposition Of the Unusually Thick Marlboro Claymentioning

confidence: 99%

“…Wright & Schaller [19] provided the first ultra-high-resolution stable carbon and oxygen isotope record through the onset of the CIE, and further suggested that the onset was decadal in scale based on cyclic sedimentary features in the Marlboro Clay unit, which contains the P-E boundary on the North American Atlantic Coastal Plain. Though this was met with significant criticism [20][21][22], it prompted a much more intense look at the CIE interval in the basal Marlboro Clay. While extracting foraminifera from the CIE onset of these shelf cores (figure 1), Schaller et al [18] serendipitously found impact ejecta (glass spherules) in a discrete horizon coincident with the CIE onset (figure 1).…”

Section: Introductionmentioning

confidence: 99%

The extraterrestrial impact evidence at the Palaeocene–Eocene boundary and sequence of environmental change on the continental shelf

Schaller

Fung

2018

Phil. Trans. R. Soc. A.

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We have identified clear evidence of an extraterrestrial impact within the onset of the carbon isotope excursion (CIE) that defines the Palaeocene-Eocene (P-E) boundary hyperthermal event (approx. 56 Ma) from several sites on the eastern Atlantic Coastal Plain and offshore. We review and update the state of the evidence for an impact at the P-E boundary, including a K-Ar cooling age of the ejecta that is indistinguishable from the depositional age at the P-E, which establishes the ejecta horizon as an isochronous stratigraphic indicator at the P-E. Immediately above the ejecta peak at the base of the coastal plain Marlboro Clay unit, we identify a sharp increase in charcoal abundance coincident with the previously observed dramatic increase in magnetic nanoparticles of soil pyrogenic origin. We therefore revisit the observed sequence of events through the P-E boundary on the western Atlantic Coastal Plain, showing that an extraterrestrial impact led to wildfires, landscape denudation and deposition of the thick Marlboro Clay, whose base coincides with the spherule horizon and CIE onset. The Sr/Ca ratio of the spherules indicates that the carbon responsible for the onset may be vaporized CaCO target rock mixed with isotopically light carbon from the impactor or elsewhere. Crucially, we do not argue that the impact was responsible for the full manifestation of the CIE observed globally (onset to recovery approx. 170 kyr), rather that a rapid onset was triggered by the impact and followed by additional carbon from other processes such as the eruption of the North Atlantic Igneous Province. Such a scenario agrees well with recent modelling work, though it should be revisited more explicitly.This article is part of a discussion meeting issue 'Hyperthermals: rapid and extreme global warming in our geological past'.

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Climate Change, Ocean Chemistry, and the Evolution of Reefs Through Time

Jury

Jokiel

2016

Coral Reefs of the World

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Reply to Pearson and Nicholas, Stassen et al., and Zeebe et al.: Teasing out the missing piece of the PETM puzzle

Cited by 6 publications

References 15 publications

Constraints on the onset duration of the Paleocene–Eocene Thermal Maximum

Constraints on the onset duration of the Paleocene–Eocene Thermal Maximum

The extraterrestrial impact evidence at the Palaeocene–Eocene boundary and sequence of environmental change on the continental shelf

Climate Change, Ocean Chemistry, and the Evolution of Reefs Through Time

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