Caribbean plate tilted and actively dragged eastwards by low-viscosity asthenospheric flow
Journal
Nature Communications
Journal Volume
12
Journal Issue
1
ISSN
2041-1723
Date Issued
2021-03-11
Author(s)
Abstract
The importance of a low-viscosity asthenosphere underlying mobile plates has been highlighted since the earliest days of the plate tectonics revolution. However, absolute asthenospheric viscosities are still poorly constrained, with estimates spanning up to 3 orders of magnitude. Here we follow a new approach using analytic solutions for Poiseuille-Couette channel flow to compute asthenospheric viscosities under the Caribbean. We estimate Caribbean dynamic topography and the associated pressure gradient, which, combined with flow velocities estimated from geologic markers and tomographic structure, yield our best-estimate asthenospheric viscosity of (3.0 ± 1.5)*1018 Pa s. This value is consistent with independent estimates for non-cratonic and oceanic regions, and challenges the hypothesis that higher-viscosity asthenosphere inferred from postglacial rebound is globally-representative. The active flow driven by Galapagos plume overpressure shown here contradicts the traditional view that the asthenosphere is only a passive lubricating layer for Earth’s tectonic plates.
Subjects
oceanic regions
asthenosphere
Caribbean plate
channel flow
flow velocity
plate tectonics
Postglacial
postglacial rebound
tilt
tomography
topography
viscosity
Article
asthenospheric upwelling
Caribbean Islands
dynamics
flow rate
pressure gradient
SDGs
Publisher
Springer Science and Business Media LLC
Type
journal article