SOULE, GREGORY S., Department of Geology and Geophysics, Univ. of Calgary, Calgary, Alberta

ABSTRACT: Structure and Stratigraphy of the Southern Alberta Foothills, Grease Creek Syncline Area

The structure at the eastern edge of the southern Alberta Foothills, known as the Triangle Zone, is formed by the delamination of foreland basin strata and the eastward wedging of a duplex along the delaminated horizon. This structure is shown to have an en echelon-surface expression in the Grease Creek Syncline area. Structural variations along strike, which cause the en echelon geometry, are investigated.

The structural evolution of the Foothills belt is examined to determine the predictability of the initiation of Foothills structures. The blind duplexes which form the Triangle Zone are repeatedly developed throughout the Foothills belt. These structural culminations appear to have a periodicity which may be defined by balanced and restored cross-sections. The style of the complex geometry within duplexes is also of interest to exploration and development of hydrocarbon reservoirs in compressional belts, since the subsurface geometry is different from the surface expression of the Triangle Zone. This study combines field work with the subsurface borehole and available seismic data in an integrated approach to a structural investigation and an analogy for the study of other similar com ressional structures.

AAPG Search and Discovery Article #90987©1993 AAPG Annual Convention, New Orleans, Louisiana, April 25-28, 1993.