A general inverse method for modelling extensional sedimentary basins

A two-dimensional inverse model for extracting the spatial and temporal var iation of strain rate from extensional sedimentary basins is presented and applied. This model is a generalization of a one-dimensional algorithm whic h minimizes the misfit between predicted and observed patterns of basin sub sidence. Our calculations include the effects of two-dimensional conduction and advection of heat as well as flexural rigidity. More importantly, we m ake no prior assumptions about the duration, number or intensity of rifting periods. Instead, the distribution of strain rate is permitted to vary smo othly through space and time until the subsidence misfit has been minimized . We have applied this inversion algorithm to extensional sedimentary basin s in a variety of geological settings. Basin stratigraphy can be accurately fitted and the resultant spatiotemporal distributions of strain rate are c orroborated by independent information about the number and duration of rif ting episodes. Perhaps surprisingly, the smallest misfits are achieved with flexural rigidities close to zero. Spatiotemporal strain rate distribution s will help to constrain the dynamical evolution of thinning continental li thosphere. The strain rate pattern governs the heat-flow history and so two -dimensional inversion can be used to construct accurate maturation models. Finally, our inversion algorithm is a stepping stone towards a generalized three-dimensional implementation.