ORCID Profile
0000-0002-7717-2092
Current Organisation
University of Southampton
Does something not look right? The information on this page has been harvested from data sources that may not be up to date. We continue to work with information providers to improve coverage and quality. To report an issue, use the Feedback Form.
Publisher: Wiley
Date: 17-05-2019
DOI: 10.1111/TER.12400
Publisher: Elsevier BV
Date: 03-2017
Publisher: Research Square Platform LLC
Date: 22-03-2021
DOI: 10.21203/RS.3.RS-333061/V1
Abstract: The early Cenozoic exhibited profound environmental change influenced by plume magmatism, continental breakup, and opening of the North Atlantic Ocean. Global warming culminated in the transient (170 thousand year, kyr) hyperthermal event, the Palaeocene-Eocene thermal maximum (PETM) 56 million years ago (Ma). Although sedimentary methane release has been proposed as a trigger, recent studies have implicated carbon dioxide (CO 2 ) emissions from the coeval North Atlantic igneous province (NAIP). However, we calculate that volcanic outgassing from mid-ocean ridges and large igneous provinces associated with the NAIP yields only one-fifth of the carbon required to trigger the PETM. Rather, we show that volcanic sequences spanning the rift-to-drift phase of the NAIP exhibit a sudden and ∼220-kyr-long intensification of volcanism coincident with the PETM, and driven by substantial melting of the sub-continental lithospheric mantle (SCLM). Critically, the SCLM is enriched in metasomatic carbonates and is a major carbon reservoir. We propose that the coincidence of the Iceland plume and emerging asthenospheric upwelling disrupted the SCLM and caused massive mobilization of this deep carbon. Our melting models and coupled tectonic–geochemical simulations indicate the release of 4 gigatons of carbon, which is sufficient to drive PETM warming. Our model is consistent with anomalous CO 2 fluxes during continental breakup, while also reconciling the deficit of deep carbon required to explain the PETM.
Publisher: Elsevier BV
Date: 09-2018
Publisher: American Geophysical Union (AGU)
Date: 17-06-2015
DOI: 10.1002/2015GL064519
Publisher: Springer Science and Business Media LLC
Date: 29-08-2022
Publisher: Copernicus GmbH
Date: 28-03-2022
DOI: 10.5194/EGUSPHERE-EGU22-11544
Abstract: & & The fundamental drivers of Phanerozoic climate change over geological timescales (10& #8211 s of Ma) are well recognised: degassing from the deep-earth puts carbon into the atmosphere, silicate weathering takes carbon from the atmosphere and traps it in carbonate minerals. A number of variables are purported to control or exert influence on these two mechanisms, such as the motion of tectonic plates varying the amount of degassing, the palaeogeogrpahic distribution of continents and oceans, the colonisation of land by plants and preservation of more weatherable material, such as ophiolites. We present a framework, & em& ySCION,& /em& that integrates these drivers into a single analysis, connecting solid earth with climate and biogeochemistry. Further, our framework allows us to isolate in idual drivers to determine their importance, and how it changes through time. Our model, with all drivers active, successfully reproduces the key aspects and trends of Phanerozoic temperature, to a much greater extent than previous models. We find that no single driver can explain Phanerozoic temperature with any degree of confidence, and that the most important driver varies for each geological period.& &
Publisher: Springer Science and Business Media LLC
Date: 23-06-2022
Publisher: Integrated Ocean Drilling Program
Date: 08-01-2016
Publisher: American Geophysical Union (AGU)
Date: 07-2016
DOI: 10.1002/2015GC006053
Publisher: Springer Science and Business Media LLC
Date: 23-08-2021
Publisher: Springer Science and Business Media LLC
Date: 07-07-2021
DOI: 10.1038/S41467-021-24439-4
Abstract: The snowball Earth hypothesis—that a runaway ice-albedo feedback can cause global glaciation—seeks to explain low-latitude glacial deposits, as well as geological anomalies including the re-emergence of banded iron formation and “cap” carbonates. One of the most significant challenges to snowball Earth has been sedimentological cyclicity that has been taken to imply more climate dynamics than expected when the ocean is completely covered in ice. However, recent climate models suggest that as atmospheric CO 2 accumulates, the snowball climate system becomes sensitive to orbital forcing. Here we show the presence of nearly all Milankovitch (orbital) cycles preserved in stratified banded iron formation deposited during the Sturtian snowball Earth. These results provide evidence for orbitally forced cyclicity of global ice sheets that resulted in periodic oxidation of ferrous iron. Orbital glacial advance and retreat cycles provide a simple mechanism to reconcile both the sedimentary dynamics and the enigmatic survival of multicellular life during snowball Earth.
Publisher: Research Square Platform LLC
Date: 08-12-2021
DOI: 10.21203/RS.3.RS-986686/V1
Abstract: Diamonds are erupted at Earth’s surface in volatile-rich magmas called kimberlites 1,2,3 . These enigmatic magmas, originating from depths exceeding 150 kilometres in Earth’s mantle 1 , occur in stable cratons and in pulses broadly synchronous with supercontinent cyclicity 4 . Whether their mobilization is driven by mantle plumes 5 or mechanical weakening of cratonic lithosphere 4,6 remains unclear. Here we show that most kimberlites spanning the past billion years erupted approximately 25 million years after the onset of continental fragmentation, suggesting an association with rifting processes. Our dynamic models show that physically steep lithosphere-asthenosphere boundaries formed during terminal rifting (necking) generate convective instabilities in the asthenosphere that slowly migrate many hundreds of kilometres inboard of the rift, causing destabilization of cratonic mantle keel tens of kilometres thick. Displaced lithosphere is replaced by hot, upwelling asthenosphere in the return flow, causing partial melting of carbonated mantle and variable assimilation of lithospheric material. The resulting small-volume kimberlite magmas ascend rapidly and adiabatically, exsolving amounts of carbon dioxide (CO 2 ) that are consistent with independent constraints 7 . Our model reconciles diagnostic kimberlite features including association with cratons and geochemical characteristics that implicate a common asthenospheric mantle source contaminated by cratonic lithosphere 8 . Together, these results provide a quantitative and mechanistic link between kimberlite episodicity and supercontinent cycles via progressive disruption of cratonic keels.
Publisher: Springer Science and Business Media LLC
Date: 26-07-2023
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Thomas Gernon.