Passive roof thrusting and forelandward fold propagation in scaled brittle‐ductile physical models of thrust wedges

• DOI: 10.1029/2000jb900310
• Publication Date: 2004-02-03T23:27:57Z
• Authors: Marco Bonini
• Keywords: Décollement; Brittleness

A set of scaled analogue models was performed to investigate the role a décollement layer in structural style fold‐and‐thrust belts. Silicone putty (SGM 36) has been employed represent ductile décollement, while frictional material (quartz sand) used simulate brittle behavior roof and floor sequences, situated above below respectively. In order explore wide combination strength profiles, have deformed under five distinct rates compression (0.15, 0.3, 0.45, 0.6, 1.5 cm h −1 ) employing four different thicknesses for silicone (0.1, 0.2, 0.4, 0.8 cm). Experimental results indicate that sequences exhibit two styles deformation: (1) passive duplex (PRD) geometry [e.g., Banks Warburton , 1986] (2) outward propagation folding (OFP) along Davis Engelder 1985]. PRD sequence remains relatively “stationary” being underthrust by wedge‐shaped duplex, OFP, displacement thrusts is transferred horizontally layer. Experiments suggest occurrence genetic relationship between shear stresses (at base τ b within d development or OFP geometry. For given strain rate deformation pattern depends upon /τ ratio as well absolute values. The transition field approximated curvilinear regression transition‐style experimental data points, with minimum value varying about 112 160 Pa, enter field. Syntectonic sedimentation molasse basin found inhibit into foreland but promote style. many principal characteristics belts developed basal evaporite duplexes at mountain fronts. Shear stress values inferred correlate fields predicted present study, allowing propose simple model describing mechanical natural underlain