Print this pageAbstract: Landsat Mapping of Tectonic Blocks that Show Strike Slip, Northern Great Plains, USA
George W. Shurr
Tectonic blocks of continental lithosphere in the Northern Great Plains have expression in patterns of linear features mapped on satellite images. Tectonic interpretations are based upon Landsat observations that are integrated with: (1) structural data from shallow Upper Cretaceous marker beds, (2) observations of fractures and faults made in outcrop; and (3) structural data and hydrocarbon production trends from deep Paleozoic pay zones.
In western North Dakota, linear features mapped at 1:1,000,000 on MSS bands 5 and 7, and at 1:250,000 on MSS bands 2 and 4, are interpreted to form lineament zones that bound lithosphere blocks. The center of the Williston basin is located at the intersection of two major lineament zones that trend northwest and northeast. The northwest-trending lineament zone separates two large blocks centered on Dunn and Billings Counties to the south and on Montrail County to the north. Smaller constituent blocks within these large blocks are defined by individual Landsat linear features and specific geologic structures, such as Nesson Anticline and Billings Nose. Outcrop observations of faults and fractures associated with the major northwest-trending lineament zone indicate a left-lateral displa ement component. This interpretation is consistent with strike-slip interpretations made on other margins of the large blocks and suggests regional clockwise rotation of the blocks.
Similar studies have been made in northeastern Montana and south-central South Dakota. Block hierarchy, rotation, and "scissor fault" oblique slip are characteristic of the tectonic style in the Northern Great Plains. These tectonic generalizations are important for hydrocarbon exploration because reservoir heterogeneities are often structurally controlled and because the satellite and outcrop studies are relatively inexpensive.
AAPG Search and Discovery Article #90986©1994 AAPG Annual Convention, Denver, Colorado, June 12-15, 1994