Plume‐Induced Sinking of Intracontinental Lithospheric Mantle: An Overlooked Mechanism of Subduction Initiation?

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Date
2021-02Type
- Journal Article
Citations
Cited 14 times in
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Cited 13 times in
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Abstract
Although many different mechanisms for subduction initiation have been proposed, only few of them are viable in terms of consistency with observations and reproducibility in numerical experiments. In particular, it has recently been demonstrated that intra‐oceanic subduction triggered by an upwelling mantle plume could greatly contribute to the onset and operation of plate tectonics in the early and, to a lesser degree, modern Earth. On the contrary, the initiation of intra‐continental subduction still remains underappreciated. Here we provide an overview of 1) observational evidence for upwelling of hot mantle material flanked by downgoing proto‐slabs of sinking continental mantle lithosphere, and 2) previously published and new numerical models of plume‐induced subduction initiation. Numerical modeling shows that under the condition of a sufficiently thick (>100 km) continental plate, incipient downthrusting at the level of the lowermost lithospheric mantle can be triggered by plume anomalies of moderate temperatures and without significant strain‐ and/or melt‐related weakening of overlying rocks. This finding is in contrast with the requirements for plume‐induced subduction initiation within oceanic or thinner continental lithosphere. As a result, plume‐lithosphere interactions within continental interiors of Paleozoic‐Proterozoic‐(Archean) platforms are the least demanding (and thus potentially very common) mechanism for initiation of subduction‐like foundering in the Phanerozoic Earth. Our findings are supported by a growing body of new geophysical data collected in various intra‐continental areas. A better understanding of the role of intra‐continental mantle downthrusting and foundering in global plate tectonics and, particularly, in the initiation of “classic” ocean‐continent subduction will benefit from more detailed follow‐up investigations. Show more
Permanent link
https://doi.org/10.3929/ethz-b-000474314Publication status
publishedExternal links
Journal / series
Geochemistry, Geophysics, GeosystemsVolume
Pages / Article No.
Publisher
American Geophysical UnionSubject
geodynamic modeling; intra‐continental mantle downthrusting; plate tectonics; plume‐lithosphere interaction; seismic tomography; subduction initiationOrganisational unit
03698 - Tackley, Paul / Tackley, Paul
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Show all metadata
Citations
Cited 14 times in
Web of Science
Cited 13 times in
Scopus
ETH Bibliography
yes
Altmetrics