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ABSTRACT: A Comparison of Structural Features to Linear Trends Observed on LANDSAT Imagery, Southern Illinois Basin

Alan Swenson, Timothy A. Gognat, George W. Shurr

Satellite imagery has been widely used to identify linear features that are inferred to be of tectonic origin. In cratonic settings, structural features are subtle and the correlation of linears with structural features is less certain than in well-exposed, highly deformed areas.

We have compared linear features in western Kentucky and southern Illinois identified on LANDSAT imagery with data from structural studies and from published geologic and geophysical information. In earlier studies, we measured joints at 154 stations in western Kentucky and southern Illinois. In Kentucky, late Paleozoic faults very in strike from northeast-southwest to east-west; in Illinois, the dominant strike is northeast-southwest. Individual joint stations across the area contain joint sets that are oriented parallel to the strike of nearby faults. Scattered late Paleozoic mafic dikes with a NNW-SSE trend occur within a similar trending 60 mi by 20 mi (95 km by 30 km) zone that lies across the Ohio River. Joint stations within and beyond the dike zone contain dike-parallel joint ets.

The linear features identified on the imagery reflect landscape aspects such as stream segments, topography, and vegetation patterns. Across the entire area a broad northeast-southwest trend is present on the imagery that correlates with similar trending faults and joint sets. The imagery also shows a weaker NNW-SSE trend, parallel to the mafic dike trend. In the western part of the area there is a strong northwest-southeast trend on the imagery that is aligned parallel with the Ste. Genevieve fault zone.

AAPG Search and Discovery Article #90998 AAPG Eastern Section Meeting, London, Ontario, Canada, September 10-12, 1990