Hydrocarbon accumulations in the foothills at the eastern margin of the Canadian Rocky Mountains are structurally trapped. Exploration for these hydrocarbons requires a prediction of the deep geometric configuration of potential reservoir beds in imperfectly understood areas. This prediction commonly is derived from analogies with the most appropriate of the region's typical structures, a pragmatic approach which is effective because the foothills contain a limited suite of relatively simple structural types: (1) concentric folds (with their attendant decollement), (2) low-angle thrust faults (commonly folded), (3) tear faults (generally transverse), and (4) late normal faults (commonly listric). The possible assemblage in a particular area is further restricted because i is a function of the degree of deformation and of the lithology of the deformed rocks. Intensity of deformation increases from east to west.

Regional stratigraphic changes alter the major lithologic units whereas local isopach or facies changes alter the distribution of incompetent rocks within units.

The structural styles are all "thin skinned" as the underlying Archean basement is not involved.

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