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Inversion of half-graben basins
Comparison of analogue and numerical models
Extension followed by inversion

© Susanne Buiter

Numerical experiments of basin inversion

Basin inversion is the process of shortening an extensional sedimentary basin whereby the basin fill is uplifted and partially extruded, and pre-existing faults are re-used [in the sense of Cooper et al., Geological Society Special Publication 44, 1989].

Mild to moderate basin inversion has been identified, for example, on seismic profiles in the North Sea and the Alpine foreland. It is characterised by uplift of the basin fill, folding of syn- and post-rift sediments and (partial) reactivation of normal faults. Examples of strong or complete inversion can be found in the Alps and Pyrenees. Folding, faulting, fault rotation, fault reactivation and extrusion of the basin fill play a role in the generation of sometimes complex deformational structures.

We are interested in the effect that various factors have on the development of fold and thrust structures forming during inversion of sedimentary basins. We investigate the sensitivity of the style of deformation to, for example, inherited extensional geometry, syn-rift and post-rift competence contrast, the presence of weak decollement layers, surface erosion, crustal rheology and strain softening. I use a two-dimensional visco-plastic numerical model (sopale, developed by the Geodynamics Group at Dalhousie University).

Inversion of half-graben basins

Susanne J.H. Buiter and O. Adrian Pfiffner, 2003, Numerical models of the inversion of half-graben basins, Tectonics 22 (5), 10.1029/2002TC001417
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Comparison of analogue and numerical models of inversion of a symmetric basin

We use both analogue and numerical experiments to study the inversion by shortening of a symmetric sedimentary basin. The experiments start with a pre-existing basin filled in part with weak layers simulating weak sediments.



Panien, M., S.J.H. Buiter, G. Schreurs and O.A. Pfiffner, 2006, Inversion of a symmetric basin: insights from a comparison between analogue and numerical experiments, in: Analogue and Numerical Modelling of Crustal-Scale Processes, Buiter, S.J.H. and Schreurs, G. (eds), Geological Society, London, Special Publication 253, 253-270
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Formation of extensional sedimentary basins and their subsequent inversion

The figure shows an example of the formation of a sedimentary basin by extension and its inversion through contraction. The model is 400 km wide by 35 km high, and the centre 200 km of the modelling domain are shown. Crust is pink, sediments are yellow. a) 30 km of extension, b) 50 km of extension; c) 60 km of extension, the different shades of yellow indicate different times of deposition of sediments; d) post-rift sediments; e) 10 km contraction, note the syn-inversion sediments in red; f) 30 km contraction.
The frictional strength of all model materials softens with increasing strain. The grid in the figure is used to track material properties and visualises deformation; it is not the calculation grid (which is more dense).
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