1. Plume-Induced Sinking of Intracontinental Lithospheric Mantle
- Author
-
Cloetingh, S.A.P.L., Koptev, Alexander, Kovacs, Istvan, Gerya, Taras, Beniest, Anouk, Willingshofer, E., Ehlers, Todd A., Andrić-Tomašević, Nevena, Botsyun, Svetlana, Eizenhöfer, Paul, François, Thomas, Beekman, Fred, Tectonics, Geology and Geochemistry, and Tectonics
- Subjects
010504 meteorology & atmospheric sciences ,Geography & travel ,Archean ,geodynamic modeling ,seismic tomography ,010502 geochemistry & geophysics ,01 natural sciences ,Mantle plume ,Mantle (geology) ,intra‐continental mantle downthrusting ,plate tectonics ,plume‐lithosphere interaction ,subduction initiation ,Lithosphere ,Geochemistry and Petrology ,14. Life underwater ,SDG 14 - Life Below Water ,Petrology ,0105 earth and related environmental sciences ,ddc:910 ,plume-lithosphere interaction ,Subduction ,Plume ,Plate tectonics ,Geophysics ,13. Climate action ,Seismic tomography ,intra-continental mantle downthrusting ,Geology - 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. ISSN:1525-2027
- Published
- 2021