Nicholas J White1, Detlef Hanne1, Paul Bellingham2
(1) University of Cambridge, Cambridge, United Kingdom
(2) University of Cambridge
ABSTRACT: (Keynote): A Strategy For Automatically Modelling Extensional Sedimentary Basins
A two-dimensional inverse model for extracting the spatial and temporal variation of strain rate from extensional sedimentary basins is described. Our starting point is a forward model which allows basin stratigraphy to be calculated from any given strain rate distribution. This forward model includes potentially important effects such as flexural rigidity and the two-dimensional conduction/advection of heat. Conversely, inverse modelling determines strain rate variation by minimising the misfit between predicted and observed patterns of basin subsidence. No a priori assumptions about the number, duration or intensity of rifting episodes are necessary. Instead, strain rate is allowed to vary smoothly throughout time and space. We have successfully inverted different synthetic sedimentary basin geometries which were generated by forward modelling. Sensitivity analysis and noise tests demonstrate that strain rate patterns can be recovered with confidence. The relationship between stratigraphic misfit and elastic thickness shows that usually an upper bound, but not a lower bound, for elastic thickness can be retrieved. Our general approach is applicable to any extension sedimentary basin, including highly extended passive margins, and it is the stepping stone to three-dimensional basin modelling. In an accompanying paper, we apply our inversion algorithm to Phanerozoic extensional sedimentary basins located worldwide.
AAPG Search and Discovery Article #90906©2001 AAPG Annual Convention, Denver, Colorado