Mantled porphyroclast gauges

Détails

ID Serval
serval:BIB_017D410B89B4
Type
Article: article d'un périodique ou d'un magazine.
Collection
Publications
Titre
Mantled porphyroclast gauges
Périodique
Journal of Structural Geology
Auteur(s)
Schmid D.W., Podladchikov Y.Y.
ISSN-L
0191-8141
Statut éditorial
Publié
Date de publication
2005
Peer-reviewed
Oui
Volume
27
Pages
571-585
Langue
anglais
Résumé
We investigate the behavior of the isolated mantled porphyroclast in a
shear zone. The method employed is a finite element model. Three
distinct phases, clast, mantle and matrix are present, the rheologies
are power-law with exponents ranging from 1 to 5 and the far-field
boundary condition is simple shear. The effective viscosity of the
mantle is assumed to be less than those of the clast and the matrix. We
show for which parameter sets mantled porphyroclasts reach
super-horizontal stabilization with respect to the shear plane and
sense. Clasts in natural mylonites frequently exhibit similar
orientations, which are interpreted as stable inclinations. The
systematic examination of the matrix-mantle-clast system allows for the
construction of attractor maps that can be directly used as gauges for
(i) the effective viscosity contrast between matrix and mantle, (ii) the
production rate of mantle material around the clast as a function of the
bulk shear strain, and (iii) for the total shear strain. The necessary
data required to use the attractor maps are simple geometrical
parameters that can be measured in the field, i.e. clast aspect ratio,
clast inclination versus the shear plane, mantle thickness, and mantle
and clast area. This new method successfully reproduces the
characteristics of natural porphyroclasts and is in good agreement with
data from natural shear zones. (c) 2005 Elsevier Ltd. All rights
reserved.
Création de la notice
09/10/2012 20:50
Dernière modification de la notice
03/03/2018 13:15
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