Tectonic loading in the Canadian Cordillera as recorded by mass accumulation in the Foreland Basin

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Abstract
The geometry of the Alberta foreland basin is generally the result of lithospheric loading in the adjacent Cordillera. Sedimentation within the Foreland basin was quantified by calculating mass accumulation rates to constrain loading events in time and space. Rates of mass accumulation for Cretaceous units in the basin can be classified into low, moderate, and high categories and may related to deformation events in the Canadian Cordillera. The rates of accumulation show a distinct cyclic pattern when plotted against time. There were two major episodes of rapid sedimentation from early Aptian to late Campanian time, each preceded by a period of relative quiescence. The first lasted from approximately 115 to 108 Ma. It shows a succession of rapid, moderate, and rapid sedimentation events. The second episode of rapid sedimentation lasted from approximately 95 to 90 Ma, and is characterized by three rapid sedimentation events separated by short intervals of quiescence. Order‐of‐magnitude changes in sediment accumulation in the foreland basin can be related to major deformation events in the Cordillera. Furthermore, the deformation can be located in time and space and evaluated in terms of its relative intensity. This delineation of deformation indicates that the docking of foreign terranes does not necessarily coincide with their final accretion and the associated tectonic loading.