Abstract
AbstractIt has recently been demonstrated that the interaction of a mantle plume with sufficiently old oceanic lithosphere can initiate subduction. However, the existence of large lithospheric heterogeneities, such as a buoyant plateau, in proximity to a rising plume head may potentially hinder the formation of a new subduction zone. Here, we investigate this scenario by means of 3‐D numerical thermomechanical modeling. We explore how plume‐lithosphere interaction is affected by lithospheric age, relative location of plume head and plateau border, and the strength of the oceanic crust. Our numerical experiments suggest four different geodynamic regimes: (a) oceanic trench formation, (b) circular oceanic‐plateau trench formation, (c) plateau trench formation, and (d) no trench formation. We show that regardless of the age and crustal strength of the oceanic lithosphere, subduction can initiate when the plume head is either below the plateau border or at a distance less than the plume radius from the plateau edge. Crustal heterogeneity facilitates subduction initiation of old oceanic lithosphere. High crustal strength hampers the formation of a new subduction zone when the plume head is located below a young lithosphere containing a thick and strong plateau. We suggest that plume‐plateau interaction in the western margin of the Caribbean could have resulted in subduction initiation when the plume head impinged onto the oceanic lithosphere close to the border between plateau and oceanic crust.
Highlights
Mantle plumes, which are large volumes of abnormally hot rocks, migrate upward within the mantle due to their positive buoyancy
We suggest that plume‐plateau interaction in the western margin of the Caribbean could have resulted in subduction initiation when the plume head impinged onto the oceanic lithosphere close to the border between plateau and oceanic crust
We conducted a series of numerical experiments to investigate plume‐plateau interaction and the effect of the following model parameters (Table 2): (i) the location of the plateau edge with respect to the plume head, (ii) age of the oceanic lithosphere, and (iii) strength of the lower crust
Summary
Mantle plumes, which are large volumes of abnormally hot rocks, migrate upward within the mantle due to their positive buoyancy. As a mantle plume reaches the base of the lithosphere, it results in diverse geological processes including the formation of plateaus (Bierlein & Pisarevsky, 2008; Fitton et al, 2004; Hastie & Kerr, 2010; Taylor, 2006), continental breakup (Fromm et al, 2015; Hill, 1991; Pirajno, 2000), triple‐junction rifting (Burke & Dewey, 1973; Houseman, 1990; Koptev et al, 2018), and subduction initiation (Baes et al, 2016; Gerya et al, 2015; Stern & Gerya, 2018; Ueda et al, 2008; Whattam & Stern, 2014) Among these tectonic settings, subduction zones are the only ones that represent convergent tectonics.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
