ABSTRACT: Surface Expression of Buried Precambrian Basement Structures and Boundaries on the Northeastern Flank of the Michigan Basin

John D. Herman

Magnetic and gravity data imagery were used to identify the boundaries of three major buried Precambrian basement provinces on the eastern half of Manitoulin Island, including the Southern, Eastern Granite-Rhyolite, and Grenville provinces. Automatic lineament mapping and automatic lineament trend mapping programs applied to LANDSAT MSS and digital elevation data revealed correlations between the trends of surface lineaments and the trends of buried basement structures and other boundaries mapped from potential field imagery. Within the area inferred to overlie the Grenville and Eastern Granite-Rhyolite provinces, automatically mapped LANDSAT lineaments have predominantly northeast trends, parallel to those in the basement. In the area inferred to overlie the buried South rn Province in which east-west basement trends are dominant, nearly east-west-trending surface lineaments are more common than they are to the east in the area overlying the Eastern Granite-Rhyolite Province. Manual interpretation of the LANDSAT, digital elevation, and potential field imagery shows correspondence in trends and locations between major coastal inlets and inferred buried basement boundaries. Several positive magnetic anomalies thought to be associated with middle Proterozoic granitic intrusive complexes correlate with the locations of large lakes. Particularly prominent manually mapped LANDSAT and digital elevation lineaments inferred to be the surface expressions of subsurface faults correlate with locations of basement faults manually mapped from magnetic intensity imager .

Even though the Precambrian basement may be buried by as much as 500 m of Paleozoic rock and Pleistocene glacial overburden, significant Precambrian basement control of surface features is implied by the correlations among lineaments mapped from LANDSAT, digital elevation, and potential field imagery.

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