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Titolo:
Strain localization as a key to reconciling experimentally derived flow-law data with dynamic models of continental collision
Autore:
Ellis, S; Wissing, S; Pfiffner, A;
Indirizzi:
Univ Bern, Inst Geol, CH-3012 Bern, Switzerland Univ Bern Bern Switzerland CH-3012 Inst Geol, CH-3012 Bern, Switzerland
Titolo Testata:
INTERNATIONAL JOURNAL OF EARTH SCIENCES
fascicolo: 1, volume: 90, anno: 2001,
pagine: 168 - 180
SICI:
1437-3254(200105)90:1<168:SLAAKT>2.0.ZU;2-I
Fonte:
ISI
Lingua:
ENG
Soggetto:
COMPRESSIONAL OROGENS; LOWER CRUST; DEFORMATION; TECTONICS; LITHOSPHERE; ALPS; SUBDUCTION; EVOLUTION; STRENGTH; MANTLE;
Keywords:
continental collision; flow-laws; numerical models; rheology; strength profiles;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
52
Recensione:
Indirizzi per estratti:
Indirizzo: Ellis, S Inst Geol & Nucl Sci, Lower Hutt, New Zealand Inst Geol & Nucl Sci Lower Hutt New Zealand Hutt, New Zealand
Citazione:
S. Ellis et al., "Strain localization as a key to reconciling experimentally derived flow-law data with dynamic models of continental collision", INT J E SCI, 90(1), 2001, pp. 168-180

Abstract

Published strength profiles predict strength discontinuities within and/orat the base of continental crust during compression. We use finite elementmodels to investigate the effect of strength discontinuities on continental collision dynamics. The style of deformation in model crust during continued subduction of underlying mantle lithosphere is controlled by: (1) experimental flow-law data; (2) the crustal geotherm; (3) strain localization byerosion; (4) strain-softening and other localization effects. In the absence of erosion and other factors causing strain localization, numerical models with typical geothermal gradients and frictional/ductile theologies predict diffuse crustal deformation with whole-scale detachment of crust from mantle lithosphere. This prediction is at odds with earlier model studies that only considered frictional crustal theologies and showed asymmetric, focused crustal rheologies deformation. Without localization, model deformation is not consistent with that observed in small collisional orogens such asthe Swiss Alps. This suggests that strain localization by a combination oferosion and theological effects such as strain softening must play a majorrole in focusing deformation, and that strength profiles derived under constant strain rates and uniform material properties cannot be used to infer crustal strength during collision dynamics.

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Documento generato il 05/04/20 alle ore 06:19:13