Detlef Hanne¹, Nicholas J White¹

(1) University of Cambridge, Cambridge, United Kingdom

ABSTRACT: A General Inverse Method for Extracting Information From Sedimentary Basins

A two-dimensional inverse model for extracting the spatial and temporal variation of strain rate from extensional sedimentary basins is presented and applied to a suite of basins. This model is a generalisation of a one-dimensional algorithm which minimises the misfit between predicted and observed patterns of basin subsidence. Our calculations include the effects of two-dimensional conduction and advection of heat as well as flexural rigidity. More importantly, we make no prior assumptions about the duration, number, or intensity of rifting periods. Instead, the distribution of strain rate is permitted to vary smoothly through space and time until the subsidence misfit has been minimised. We have applied this inversion algorithm to extensional sedimentary basins in a variety of geological settings. Basin stratigraphy can be accurately fitted and the resultant spatio-temporal distributions of strain rate are corroborated by independent information about the number and duration of rifting episodes. Perhaps surprisingly, the smallest misfits are achieved with flexural rigidities close to zero. Spatio-temporal strain rate distributions will help to constrain the dynamical evolution of thinning continental lithosphere. The strain rate pattern governs the heatflow history and so two-dimensional inversion can be used to construct accurate maturation models. Finally, our inversion algorithm is a stepping stone towards a generalised three-dimensional implementation.

AAPG Search and Discovery Article #90906©2001 AAPG Annual Convention, Denver, Colorado