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Abstract
Few studies specifically test the principles of sequence stratigraphy in foreland basins, where rates of accommodation and sedimentation increase from the distal portions of the basin into the foredeep. The Middle to Upper Jurassic Preuss and Stump formations of the Wyoming Range, Wyoming and Idaho, were deposited in the foredeep of the Sundance Seaway, and a facies and sequence-stratigraphic analysis was undertaken to understand how the sequence architecture of the foredeep correlates to the previously established architecture of the Jurassic strata in the Bighorn Basin. The Middle to Upper Jurassic strata of the foredeep consist of one partially complete depositional sequence and this sequence is equivalent to the J-4 sequence in the Bighorn Basin. The sequence architecture of the foredeep suggests that tectonic subsidence and the position of the shoreline in the high or low-accommodation zone play a primary control on the sequence architecture of a foreland basin.