Print this pageEvolution and Controls of Facies Architecture in a Marginal Foreland Basin (Southeastern Pyrenees, Spain): Quantification By Magnetostratigraphy and Subsidence Analysis
DOCHERTY, CRAIG, DAVE WALTHAM, and CONXITA TABERNER
High resolution, cross-basin magnetostratigraphy provides the ideal framework for the quantification of foreland basin development. Combined with lithostratigraphic correlation and well-constrained subsidence analysis, the timing and duration of tectonic events, depocenter migration and lapse times for basin infill can all be ascertained. This methodology is applied to the evolution over a c.10 Myr. period of the mixed clastic/carbonate reservoir-scale sedimentary bodies infilling the southeastern sector of the Eocene southpyrenean foreland basin, Spain. The study area is flanked to the north and south by thrust belts active during the basin's development. Quantitative analysis reveals the individual movements of thrust sheets both from foreland and hinterland, which resulted in a depocenter migratory pattern that was partly oscillatory, partly Superposed as the deformation fronts closed together. Facies architecture attests to these tectonic adjustments, where the formation of deltas and carbonates in particular are very sensitive to vertical movements at the basin's margins. One prominent erosion surface, that is not synchronous with thrust movements, can only be explained by reactivation of pre-existing basement faults. Hence this approach enables various tectonic factors that affect reservoirs in complex tectonic settings to be distinguished in time and space, with the obvious implications for basin closure and hydrocarbon migration.