Plume-induced subduction initiation: Insights from the south-western margin of the Caribbean
Final Report Abstract
Subduction zones are main components of plate tectonics and around 90% of the plate driving forces stem from the negative buoyancy of sinking lithosphere in subduction zones. However, despite their vital role, it is still enigmatic how and where subduction zones form. A recently proposed scenario that is independent of any preexisting lithospheric weakness zones is plume-induced subduction initiation. According to this scenario, the arrival of a buoyant plume beneath oceanic lithosphere results in the formation of several slabs surrounding a newly formed plateau. However, many key aspects of this new scenario have not been investigated yet. In this project we aimed to address some of these unexplored issues including: the lithosphere’s response to plateau-plume interaction, impact of regional extension on plume-plateau interaction and investigation of key parameters which play roles for the formation of a single one-sided plume-induced subduction zone. To this aim we used cutting-edge 3-d numerical models. We applied our models to the geologically most recent example of plume-induced subduction at the south-western margin of the Caribbean plate, which occurred around 100 million years ago. The outcomes of this study indicate that the lithospheric response to arrival of mantle plume depends on different parameters such as age of oceanic lithosphere, thickness and friction coefficient of crust, location of the plume head with respect to plateau edge, extension rate and existence or absence of plume tail. Based on model results, we suggest that single-slab subduction in the western Caribbean was formed due to either (a) plume-plateau interaction in an extensional regime or (b) arrival of a mantle plume beneath a lithosphere with typical crustal thickness of 8 km or (c) plume impingement onto the oceanic lithosphere close to the border between plateau and oceanic crust.
Publications
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(2020). Addressing subduction initiation: A key - but unresolved - feature of plate tectonics. EGU General Assembly 2019, 7-12 April 2019, Geophysical Research Abstracts Vol. 21, EGU2019-5956
Baes, M., Sobolev, S. V., Gerya, T., & Brune, S.
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(2020). Interaction of a mantle plume and a moving plate: insights from numerical modeling, EGU General Assembly 2020, Online, 4-8 May 2020, EGU2020-8187
Brune, S., Baes, M., Gerya, T., & Sobolev, S.
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(2020). Plume-induced subduction initiation: single- or multi-slab subduction? EGU General Assembly 2020, Online, 4-8 May 2020, EGU2020-7783
Baes, M., Sobolev, S., Gerya, T., & Brune, S.
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(2020). Plume-Induced Subduction Initiation: Single-Slab or Multi-Slab Subduction? Geochemistry Geophysics Geosystems (G3),21 (2): e2019GC008663
Baes, M., Sobolev, S. V., Gerya, T., & Brune, S.
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(2020). Subduction initiation by plume-plateau interaction: Insights from numerical models. Geochemistry Geophysics Geosystems (G3), 21 (8): e2020GC009119
Baes, M., Sobolev, S. V., Gerya, T., & Brune, S.
