Wong, K, Mason, E, Brune, S et al. (3 more authors) (2019) Deep Carbon Cycling Over the Past 200 Million Years: A Review of Fluxes in Different Tectonic Settings. Frontiers in Earth Science, 7. 263. pp. 1-22. ISSN 2296-6463
Abstract
Carbon is a key control on the surface chemistry and climate of Earth. Significant volumes of carbon are input to the oceans and atmosphere from deep Earth in the form of degassed CO2 and are returned to large carbon reservoirs in the mantle via subduction or burial. Different tectonic settings (e.g., volcanic arcs, mid-ocean ridges, and continental rifts) emit fluxes of CO2 that are temporally and spatially variable, and together they represent a first-order control on carbon outgassing from the deep Earth. A change in the relative importance of different tectonic settings throughout Earth’s history has therefore played a key role in balancing the deep carbon cycle on geological timescales. Over the past 10 years the Deep Carbon Observatory has made enormous progress in constraining estimates of carbon outgassing flux at different tectonic settings. Using plate boundary evolution modeling and our understanding of present-day carbon fluxes, we develop time series of carbon fluxes into and out of the Earth’s interior through the past 200 million years. We highlight the increasing importance of carbonate-intersecting subduction zones over time to carbon outgassing, and the possible dominance of carbon outgassing at continental rift zones, which leads to maxima in outgassing at 130 and 15 Ma. To a first-order, carbon outgassing since 200 Ma may be net positive, averaging ∼50 Mt C yr–1 more than the ingassing flux at subduction zones. Our net outgassing curve is poorly correlated with atmospheric CO2, implying that surface carbon cycling processes play a significant role in modulating carbon concentrations and/or there is a long-term crustal or lithospheric storage of carbon which modulates the outgassing flux. Our results highlight the large uncertainties that exist in reconstructing the corresponding in- and outgassing fluxes of carbon. Our synthesis summarizes our current understanding of fluxes at tectonic settings and their influence on atmospheric CO2, and provides a framework for future research into Earth’s deep carbon cycling, both today and in the past.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2019 Wong, Mason, Brune, East, Edmonds and Zahirovic. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/. |
Keywords: | deep carbon cycle; carbonate assimilation; solid Earth degassing; plate reconstructions; carbon dioxide; subduction zone |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Environment (Leeds) > School of Earth and Environment (Leeds) |
Depositing User: | Symplectic Publications |
Date Deposited: | 17 Oct 2019 14:07 |
Last Modified: | 17 Oct 2019 14:07 |
Status: | Published |
Publisher: | Frontiers Media |
Identification Number: | 10.3389/feart.2019.00263 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:152200 |