Temporal Evolution of Island Arc Magmatism and Its Influence on Long-Term Climate: Insights From the Izu Intra-Oceanic Arc

Publication type:
Journal article
Metadata:
Abstract
<jats:p>Continental arcs have an episodic magmatic activity over long-time periods, which is believed to modulate long-term climate. Island arcs have also the potential to release large amount of CO<jats:sub>2</jats:sub> into the atmosphere, but whether they display an episodic magmatic history throughout their lifespan that contributes to the long-term (&amp;gt;10 Ma) climate changes remains an open question. To set additional constraints on the magmatic history of island arcs, here we examine fresh basalts and mineral-hosted melt inclusions from the Izu intra-oceanic arc, shortly after the eruption of boninites (∼45 Ma ago). Using chemical markers, we show that the long-term magmatic activity of the mature Izu arc has been relatively continuous over its lifespan, except during opening of the Shikoku back-arc Basin (∼23–20 Ma). Because slab dehydration and slab melting trigger decarbonation and carbonate dissolution of the subducted plate, we use slab-fluid markers (Ba/Th, Cs/Th, Cs/Ba, Rb/Th, Th/Nb) to examine the variations of slab-derived CO<jats:sub>2</jats:sub> captured by the arc magmas. The long-term steadiness in the arc magmatic activity and in the slab-fluid contribution suggests that the CO<jats:sub>2</jats:sub> outgassed during mature arc volcanism may have remained relatively homogeneous for the past 40 Ma in Izu. If worldwide mature island arcs also maintain a relatively steady-state magmatic activity over their lifespan, the long-term CO<jats:sub>2</jats:sub> outgassed by these arc volcanoes may be rapidly balanced by chemical weathering and tectonic erosion, which rapidly draw down the atmospheric CO<jats:sub>2</jats:sub> (within 200–300 kyr). This rapid negative feedback to long-term volcanic degassing permits to sustain a viable atmospheric CO<jats:sub>2</jats:sub> for millions of years. The lack of co-variations between the markers of climate changes (δ<jats:sup>13</jats:sup>O, δ<jats:sup>18</jats:sup>C) and the long-term averages of the markers of slab fluids further implies that long-term volcanic degassing of CO<jats:sub>2</jats:sub> from mature island arcs might play a minor role in the slide into icehouse climatic conditions. This long-term degassing stability may be, instead, a contributor to maintaining a broadly stable climate over long timescales.</jats:p>
Autoren
  • Julia M Ribeiro
  • Osamu Ishizuka
  • Philip AE Pogge von Strandmann
  • Yoshihiko Tamura
  • Yi-Gang Xu
DOI
10.3389/feart.2022.810597
eISSN
2296-6463
Zeitschrift
Frontiers in Earth Science
Online publication date
2022
Status
Published online
Herausgeber
Frontiers Media SA
Herausgeber URL
http://dx.doi.org/10.3389/feart.2022.810597
Datum der Datenerfassung
2022
Titel
Temporal Evolution of Island Arc Magmatism and Its Influence on Long-Term Climate: Insights From the Izu Intra-Oceanic Arc
Ausgabe der Zeitschrift
10

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