Large Igneous Province thermogenic greenhouse gas flux could have initiated Paleocene-Eocene Thermal Maximum climate change

Jones, S. M.; Hoggett, Murray; Greene, Sarah E.; Jones, Tom Dunkley

doi:10.1038/s41467-019-12957-1

Cited by 45 publications

(32 citation statements)

References 56 publications

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“…Assuming that magma-derived CO 2 mixed with thermogenic methane, our reconstruction allows a mean contribution of 17%, with an upper bound of 77%. In comparison, recent modeling of sill intrusion associated with NAIP concluded that thermogenic methane contributed 80 to 90% of PETM carbon, with mantle-derived CO 2 providing a much smaller amount (32). Boron proxy-derived DIC records therefore allow for a lesser, but still significant, role for thermogenic methane in PETM carbon release.…”

Section: Discussionmentioning

confidence: 90%

The seawater carbon inventory at the Paleocene–Eocene Thermal Maximum

Haynes

Hönisch

2020

Proc. Natl. Acad. Sci. U.S.A.

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The Paleocene–Eocene Thermal Maximum (PETM) (55.6 Mya) was a geologically rapid carbon-release event that is considered the closest natural analog to anthropogenic CO2 emissions. Recent work has used boron-based proxies in planktic foraminifera to characterize the extent of surface-ocean acidification that occurred during the event. However, seawater acidity alone provides an incomplete constraint on the nature and source of carbon release. Here, we apply previously undescribed culture calibrations for the B/Ca proxy in planktic foraminifera and use them to calculate relative changes in seawater-dissolved inorganic carbon (DIC) concentration, surmising that Pacific surface-ocean DIC increased by +1,010−646+1,415 µmol/kg during the peak-PETM. Making reasonable assumptions for the pre-PETM oceanic DIC inventory, we provide a fully data-driven estimate of the PETM carbon source. Our reconstruction yields a mean source carbon δ13C of −10‰ and a mean increase in the oceanic C inventory of +14,900 petagrams of carbon (PgC), pointing to volcanic CO2 emissions as the main carbon source responsible for PETM warming.

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Section: Discussionmentioning

confidence: 90%

The seawater carbon inventory at the Paleocene–Eocene Thermal Maximum

Haynes

Hönisch

2020

Proc. Natl. Acad. Sci. U.S.A.

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“…Most work has focused on the generation of greenhouse gases in contact aureole as sills were emplaced into organic rich sediments (e.g., Svensen et al, 2004), leading to organic carbon remineralization and/or thermogenic methanogenesis (Storey et al, 2007), causing the CIE and most of the PETM warming. Jones et al (2019) recently showed that this mechanism can plausibly produce carbon at a sufficient rate. Converting this to a dSi flux would require knowledge of the compositional change of intruded sediment, but our box model (Figure 5, Scenario O) suggests a ~100 times increase in hydrothermally sourced Si is required to explain the radiolarian δ 30 Si excursion.…”

Section: Discussionmentioning

confidence: 99%

“…This factor would increase if late Paleocene river δ 30 Si were lower than today, as might be expected. Jones et al (2019) calculate peak excess magmatic carbon release rates from the NAIP of ~2 × 10 12 mol C year −1 . This is of the same order of magnitude as modern magmatic MOR degassing estimates (Dasgupta & Hirschmann, 2010; see above).…”

Section: Discussionmentioning

confidence: 99%

Constraints on Earth System Functioning at the Paleocene‐Eocene Thermal Maximum From the Marine Silicon Cycle

Fontorbe

Frings

Rocha³

et al. 2020

Paleoceanog and Paleoclimatol

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The Paleocene-Eocene Thermal Maximum (PETM, ca. 56 Ma) is marked by a negative carbon isotope excursion (CIE) and increased global temperatures. The CIE is thought to result from the release of 13 C-depleted carbon, although the source(s) of carbon and triggers for its release, its rate of release, and the mechanisms by which the Earth system recovered are all debated. Many of the proposed mechanisms for the onset and recovery phases of the PETM make testable predictions about the marine silica cycle, making silicon isotope records a promising tool to address open questions about the PETM. We analyzed silicon isotope ratios (δ 30 Si) in radiolarian tests and sponge spicules from the Western North Atlantic (ODP Site 1051) across the PETM. Radiolarian δ 30 Si decreases by 0.6‰ from a background of 1‰ coeval with the CIE, while sponge δ 30 Si remains consistent at 0.2‰. Using a box model to test the Si cycle response to various scenarios, we find the data are best explained by a weak silicate weathering feedback, implying the recovery was mostly driven by nondiatom organic carbon burial, the other major long-term carbon sink. We find no resolvable evidence for a volcanic trigger for carbon release, or for a change in regional oceanography. Better understanding of radiolarian Si isotope fractionation and more Si isotope records spanning the PETM are needed to confirm the global validity of these conclusions, but they highlight how the coupling between the silica and carbon cycles can be exploited to yield insight into the functioning of the Earth system.

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“…Lateral migration of melts has also been well documented in the Faroe Shetland Basin and Hebrides areas to the south (Hole et al 2015;Schofield et al 2017). In the Faroe-Shetland Basin, it has been proposed that dynamic topography, evidenced from seismically imaged incision envelopes within the Faroe-Shetland Basin, resulted from the convective spreading of buoyant hotter than ambient mantle beneath the lithosphere, a process attributed by several authors to pulsing of the proto-Iceland plume (Shaw-Champion et al 2008;Saunders et al 2007;Jones et al 2019). To the east of the Faroe Islands in the NE Faroe-Shetland Basin, Millett et al (2015) provided the first stratigraphically constrained petrological evidence for a linkage between dynamic changes in mantle melting and relative uplift and subsidence within the Faroe-Shetland Basin at the 217/15-1Z borehole.…”

Section: Regional Implicationsmentioning

confidence: 99%

Transient mantle cooling linked to regional volcanic shut-down and early rifting in the North Atlantic Igneous Province

et al. 2020

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The Paleocene to Early Eocene Faroe Islands Basalt Group (FIBG) comprises a c. 6.5-km-thick lava flow-dominated sequence located within the centre of the North Atlantic Igneous Province (NAIP). The currently defined pre-breakup and syn-breakup sequences of the FIBG are separated by a significant volcanic hiatus, during which time the coal-bearing Prestfjall Formation was deposited. This major volcanic hiatus is identified across large parts of the NAIP and was preceded on the Faroe Islands by a reduction in eruption rate evidenced by an increased number and thickness of inter-lava sedimentary beds between the simple lava flows of the pre-breakup Beinisvørd Formation. High tempo eruptions resumed after this hiatus with the development of the compound lava flow fields of the Malinstindur Formation which reveal limited evidence for inter-lava breaks. In order to investigate this key transition, flow by flow geochemical sampling of a composite c.1.1-km-thick lava flow sequence spanning this transition were collected and analysed. Three chemically distinct groups are defined based on rare earth elements (REEs) and incompatible trace element signatures. Two high-Ti groups (TiO 2 > 2 wt%), B2 and B3, dominate the sampled Beinisvørd Formation and display light REE-enriched signatures (La/Yb N c. 2.9-5.9) and evidence for garnet in the source melting region (Dy/Yb N c. 1.5-1.6). At the very top of the Beinisvørd Formation, a distinct group of lava flows, B1, displaying lower TiO 2 for a given MgO wt% (TiO 2 c. 1-2 wt%), weakly light REE-enriched profiles (La/Yb N c. 1.7-2.4) and a spinel-dominated mantle melting signature (Dy/Yb N c. 1.1-1.2) is identified. Sr, Nd and Pb isotopic signatures for the three groups overlap, revealing limited evidence of crustal contamination, and therefore supporting a mantle melting origin for inter-group variations, rather than source composition or contamination. The group B1 lava flows form a unique stratigraphic occurrence on the islands and provide clear evidence for both a reduction in the initial pressure of melting, alongside an increase in the overall degree of partial melting relative to groups B2 and B3. Increased partial melting is interpreted as evidence for the early onset of rifting and lithospheric thinning to the north of the Faroe Islands. The accompanying reduction in initial pressure of melting provides the first petrological evidence that a transient reduction in mantle temperature leads to the province-wide volcanic hiatus. Our study demonstrates an intimate linkage between rifting history and fluctuations in mantle temperature highlighting that any over-arching model for the evolution of the NAIP must take both into equal account.

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Large Igneous Province thermogenic greenhouse gas flux could have initiated Paleocene-Eocene Thermal Maximum climate change

Cited by 45 publications

References 56 publications

The seawater carbon inventory at the Paleocene–Eocene Thermal Maximum

The seawater carbon inventory at the Paleocene–Eocene Thermal Maximum

Constraints on Earth System Functioning at the Paleocene‐Eocene Thermal Maximum From the Marine Silicon Cycle

Transient mantle cooling linked to regional volcanic shut-down and early rifting in the North Atlantic Igneous Province

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