Post-rift compressional reactivation potential of passive margins and extensional basins
Published:January 01, 2008
Sierd Cloetingh, Fred Beekman, Peter A. Ziegler, Jan-Diederik Van Wees, Dimitrios Sokoutis, 2008. "Post-rift compressional reactivation potential of passive margins and extensional basins", The Nature and Origin of Compression in Passive Margins, Howard Johnson, Tony G. Doré, Robert W. Gatliff, Robert W. Holdsworth, Erik R. Lundin, J. Derek Ritchie
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Poly-phase deformation of a compressional nature is a common feature in the post-rift evolution of passive margins and rifts. The compressional mode of deformation in these sedimentary basins, originally formed by extension in an intraplate setting, is characterized by a spectrum of spatial wavelengths spanning several tens of kilometres up to several hundreds of kilometres. The actual mode of compressional deformation appears to be strongly affected by the rheological structure of the underlying lithosphere, the level of the regional intraplate stress field, and the geometry of the rifted basin configuration prior to late-stage compressional reactivation. The interplay of plumes and intraplate compressional deformation can lead to temporal transitions from basin inversion to lithospheric folding. These modes of deformation lead to substantial differential vertical motions, late-stage anomalies in subsidence and uplift patterns. The development of innovative combinations of numerical and analogue modelling techniques is the key to differentiating different modes of compressional deformation of passive margins and extensional basins.
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The Nature and Origin of Compression in Passive Margins
Increasingly, researchers have reported that passive margins do not show a simple uninterrupted thermal sag pattern of post-rift subsidence following continental separation. Rather, the structural and stratigraphic development of such margins may record evidence of complex phases of differential subsidence, exhumation and fold development. Some of the fold structures observed on passive continental margins appear to be related to regional stresses transmitted through basement rocks, whereas others are related to gravitational sliding and toe-thrusting. This special publication concentrates on the first of these categories. The morphology and distribution of such folds, together with potential mechanisms for generation of regional stress, are described in a series of papers by authorities in the field. As well as being an enigmatic feature of passive margin geology, the compressive folds have significance in the exploration for petroleum.