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Extrusion vs. accretion at the frictional–viscous décollement transition in experimental thrust wedges: the role of convergence velocity
Author(s) -
Luján María,
Storti Fabrizio,
Rossetti Federico,
CrespoBlanc Ana
Publication year - 2006
Publication title -
terra nova
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.353
H-Index - 89
eISSN - 1365-3121
pISSN - 0954-4879
DOI - 10.1111/j.1365-3121.2006.00685.x
Subject(s) - décollement , geology , wedge (geometry) , thrust , asymmetry , geomorphology , geometry , seismology , physics , tectonics , mathematics , quantum mechanics , thermodynamics
In many cases, thrust wedges accreted at shallow crustal levels show an across‐strike rheological variability along the basal décollement, notably from brittle to ductile behaviour. In this paper, we illustrate the results of sandbox analogue modelling research devoted to studying the influence of convergence velocity on wedge architecture when laterally juxtaposed frictional and viscous materials occur along the basal décollement of accreting thrust wedges. Our results show that slow convergence favours a near symmetrical distribution of thrust vergence within wedge sectors accreted above viscous décollement material, whereas fast convergence favours vergence asymmetry. In particular, at fast convergence rates the hinterlandward extrusion of viscous décollement material at the toe of the frictional wedge is favoured and contributed to accommodate a significant amount of the total contraction. Terra Nova, 18, 241–247, 2006