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Analogue Modelling |
Fault Dynamics Project, Geology Department, Royal Holloway University of London, Egham, Surrey, TW20 0EX, UK
Scaled analogue modelling is a powerful tool for the understanding of the geometric and kinematic development of extensional, strike-slip and inverted fault systems, as well as for some thrust systems. In this paper the results of 2D and 3D scaled analogue model experiments designed to simulate listric fault systems, rift fault systems, and inverted listric faults are reviewed. Simple 2D rift models are characterized by asymmetric rift graben structures with planar rift border faults and domino-style intra-rift fault systems. 2D listric fault models produce roll-over anticlines with associated crestal collapse grabens whereas the ramp-flat listric fault models produce roll-over anticlines associated with each concave-up segment of the main fault system and also a syncline above the convex-up ramp section of the main detachment. The 2D analogue models are directly comparable to natural examples of extensional fault systems. The results of simple 3D analogue models of an orthogonal and a 60° oblique rift are presented. Orthogonal rift models are characterized by both rift-border and intra-rift faults that are nearly orthogonal to the extension direction. Like-dipping intra-rift faults overlap to form relay ramps that transfer displacement between the faults. In contrast oblique rift models are characterized by en-echelon arrays of segmented extensional faults. Rift border fault systems are parallel to the underlying zone of basement stretching whereas the intra-rift faults are segmented and at a high angle to the extension direction. Oblique accommodation zones formed by interlocking conjugate fault arrays separate individual depocentres within the models. No strike-slip or oblique-slip transfer faults are found in these models. The 3D rift models produce fault patterns that are comparable with natural examples of rift systems. Analogue modelling of inverted listric faults is described and the results compared with natural examples of inverted fault systems. The results of the scaled analogue models described in this paper provide important constraints on section interpretation and restoration in that they permit an understanding of the geometric and kinematic evolution of fault (and fold) structures as well as indicating the sequences of faulting and activity on faults. They provide templates for the interpretation of seismic sections in regions of poor data quality and for projecting surface data into the sub-surface.
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  A. Benedicto, M. Seguret, and P. Labaume Interaction between faulting, drainage and sedimentation in extensional hanging-wall syncline basins: example of the Oligocene Matelles basin (Gulf of Lion rifted margin, SE France) Geological Society, London, Special Publications, 1999; 156: 81 - 108. [Abstract] [PDF]
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