HR: 17:30h
AN: T34A-05    [Abstracts]
TI: Effect of Cohesion Uncertainty of Granular Materials on the Kinematics of Scaled Models of Fold-and-Thrust Belts
AU: * Nilfouroushan, F
EM: farnil@geology.utoronto.ca
AF: University of Toronto, Earth Sciences Center,22 Russell Street, Toronto, ON M5S3B1, Canada
AU: Pysklywec, R
EM: russ@geology.utoronto.ca
AF: University of Toronto, Earth Sciences Center,22 Russell Street, Toronto, ON M5S3B1, Canada
AU: Cruden, S
EM: cruden@geology.utoronto.ca
AF: University of Toronto, Earth Sciences Center,22 Russell Street, Toronto, ON M5S3B1, Canada
AB: Cohesionless or very low cohesion granular materials are widely used in analogue/physical models to simulate brittle rocks in the upper crust. Selection of materials with appropriate cohesion values in such models is important for the simulation of the dynamics of brittle rock deformation in nature. Uncertainties in the magnitude of cohesion (due to measurement errors, extrapolations at low normal stresses, or model setup) in laboratory experiments can possibly result in misinterpretation of the styles and mechanisms of deformation in natural fold-and thrust belts. We ran a series of 2-D numerical models to investigate systematically the effect of cohesion uncertainties on the evolution of models of fold-and-thrust belts. The analyses employ SOPALE, a geodynamic code based on the arbitrary Lagrangian-Eulerian (ALE) finite element method. Similar to analogue models, the material properties of sand and transparent silicone (PDMS) are used to simulate brittle and viscous behaviors of upper crustal rocks. The suite of scaled brittle and brittle-viscous numerical experiments have the same initial geometry but the cohesion value of the brittle layers is increased systematically from 0 to 100 Pa. The stress and strain distribution in different sets of models with different cohesion values are compared and analyzed. The kinematics and geometry of thrust wedges including the location and number of foreland- and hinterland- verging thrust faults, pop-up structures, tapers and topography are also explored and their sensitivity to cohesion value is discussed.
DE: 8020 Mechanics, theory, and modeling
DE: 8104 Continental margins: convergent
DE: 8108 Continental tectonics: compressional
DE: 8160 Rheology: general (1236, 8032)
SC: Tectonophysics [T]
MN: 2009 Joint Assembly