Mechanical model for the tectonics of doubly vergent compressional orogens

A mechanical model of crustal shortening and deformation driven by the relative convergence of rigid, underlying mantle plates explains many features of convergent orogens. Results based on numerical models and supported by sandbox models show that a Coulomb crustal layer subject to basal velocity b...

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Bibliographic Details
Published in:Geology (Boulder) 1993-04, Vol.21 (4), p.371-374
Main Authors: Willett, Sean, Beaumont, Christopher, Fullsack, Philippe
Format: Article
Language:English
Subjects:
accretionary wedges
active margins
basins
fore-arc basins
Geology
Geophysics
Lithoprobe
mechanism
orogeny
plate collision
plate convergence
Plate tectonics
solid Earth (tectonophysics)
Structural geology
subduction
tectonics
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Summary:A mechanical model of crustal shortening and deformation driven by the relative convergence of rigid, underlying mantle plates explains many features of convergent orogens. Results based on numerical models and supported by sandbox models show that a Coulomb crustal layer subject to basal velocity boundary conditions corresponding to asymmetric detachment and subduction of the underlying mantle passes through three stages of orogenic growth: (1) block uplift bounded by step-up shear zones; (2) development of a low-taper wedge over the underthrusting mantle plate; and (3) development of a low-taper wedge overlying the overthrusting mantle plate and verging in the opposite direction. When modified by isostasy, basal viscous flow, surface erosion and denudation, and sedimentation, the resultant model orogens exhibit a variety of styles with characteristics in common with small, rapidly denuded orogens, large orogens with plateaus and extensional characteristics, and active subduction margins with doubly vergent accretionary wedges and deformed fore-arc basins.
ISSN:0091-7613
1943-2682
DOI:10.1130/0091-7613(1993)021<0371:MMFTTO>2.3.CO;2