On modelling the lithosphere in mantle convection with non-linear rheology
Item
Title (Dublin Core)
en-US
On modelling the lithosphere in mantle convection with non-linear rheology
Description (Dublin Core)
en-US
Numerical convection experiments were carried out with the aim of simulating the lithosphere as a strong mechanical boundary layer participating in the circulation, and to study its dynamical role and the governing parameters. The rheological model parameters were successively refined, effective viscosity depending on (1) depth, (2) temperature and pressure, and (3) temperature, pressure, and stress. In all cases a high-viscosity plate rested on a low-viscosity asthenosphere; in the two latter cases it could in principle subduct, but did so only if zones of weakness were built into it. It was possible to model active or inactive plates (moving faster or slower than the asthenosphere below). Because of a lack of numerical resolution it was however, not possible to simulate a narrow sinking slab; rather a broad zone of cooled and highly viscous material developed, often limiting the rate of descent and leading to non-steady convection. The circulation, including subduction, was stabilized by introduction of stress-dependence of viscosity (non-linearity), dissipation, and adiabatic heating. The parameter chiefly responsible for deciding the (active or passive) role of the plate is its decoupling from its neighbours, achieved in the models by assuming weakness zones. Another important result seems to be that the assumption of plausible mantle rheologies and heat input leads to equally plausible effective viscosities, plate velocities, and to upper-mantle temperatures which are relatively low by current ideas, but conforming to earlier estimates based on convection theory. Viscosity distribution and flow pattern are also in reasonable agreement with more detailed boundary layer computations. The main obstacles to our modelling are the numerical limitations, forcing upon us such artificialities as two-dimensionality, rectangular model boxes, coarse grids, and generalized weakness zones.
ARK: https://n2t.net/ark:/88439/y061130
Permalink: https://geophysicsjournal.com/article/176
ARK: https://n2t.net/ark:/88439/y061130
Permalink: https://geophysicsjournal.com/article/176
Creator (Dublin Core)
Schmeling, H.
Jacoby, W.R.
Subject (Dublin Core)
en-US
Mantle convection
en-US
Finite-difference model
en-US
Rheology
en-US
Mantle temperatures
en-US
Lithosphere
en-US
Solid Earth
Publisher (Dublin Core)
en-US
Journal of Geophysics
Date (Dublin Core)
1981-10-22
Type (Dublin Core)
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
en-US
Peer-reviewed Article
Format (Dublin Core)
application/pdf
Identifier (Dublin Core)
https://journal.geophysicsjournal.com/JofG/article/view/176
Source (Dublin Core)
en-US
Journal of Geophysics; Vol 50 No 1 (1982): Journal of Geophysics; 89-100
2643-2986
2643-9271
Language (Dublin Core)
eng
Relation (Dublin Core)
https://journal.geophysicsjournal.com/JofG/article/view/176/136