4-D Evolution of Fold and Thrust Belts

Ken McClay, Fault Dynamics Research Group, Royal Holloway University of London, Egham, TW20 0EX, United Kingdom, phone: +44 1784 443618, fax: +44 1784 471780, ken@gl.rhul.ac.uk, Jose De Vera, Fault Dynamics Research Group, Royal Holloway, University of London, Egham, Surrey, TW20 0EX, United Kingdom, and P. Whitehouse, Fault Dynamics Research Group, Royal Holloway University of London, Department of Geology, Royal Holloway University of London, Egham Surrey, TW20 0EX, United Kingdom.

New three-dimensional analogue sandbox modelling experiments have been used to simulate the 4D evolution of thrust belts both in delta toes and in accretionary wedges. High-resolution digital photography, digital laser scanning and 3D reconstructions have been combined to produce quantitative models of thrust belt systems. This paper focuses upon the initiation, growth and linkage of faults at the early stages of thrust evolution as well as segmentation and curvatures within thrust belts. In all models Colomb thrust wedges were developed with the internal geometries strongly controlled by the nature of the basal detachment layers. Low taper wedges were formed where ductile polymer and low friction basal detachments were used whereas high taper wedges formed where sand detachment layers were used. Along-strike segmentation and curvatures in thrust belts were induced where basal detachment characteristics varied across the model and also where syntectonic erosion and sedimentation occurred. Along-strike changes in thicknesses of layers across lateral and oblique ramps induced fold plunge terminations and transfer/accommodation zones within the model thrust belts. The results of the analogue models are compared to segmentation and along strike changes in natural thrust and fold systems such as those found in deepwater fold belts offshore northern Borneo or in terrestrial fold belts such as the Canadian Rocky Mountains and the Zagros fold belt of Iran.

Structural Styles and Play/Prospect Implications
2006 AAPG International Conference and Exhibition, (November 5-8, 2006) Technical Program