Regional-scale Geologic Interpretation
of Seismic Reflection, Gravity, and Magnetic Profiles
Collected along the Western Arm of the Midcontinent Rift System,
Upper Peninsula of Michigan, Wisconsin, Minnesota and Iowa

Wisconsin Geological and Natural History Survey Open-file Report 2002-01, 18 p. +

Albert B. Dickas

Department of Geology
University of Wisconsin-Superior
Superior, Wisconsin 54880 -2898

Now at:

1355 Jefferson Forest Lane
Blacksburg, Virginia 24060

Michael G. Mudrey, Jr.

Wisconsin Geological and Natural History Survey
University of Wisconsin-Extension
3817 Mineral Point Road
Madison, Wisconsin 53705-5100
email mgmudrey@wisc.edu

ABSTRACT

In 1984 and early 1985 the western arm of the Midcontinent Rift System (MRS) was geophysically sampled by a series of reflection seismology, gravity, and magnetic profiles. This program, totaling approximately 1340 km. (833 mi), was undertaken in response to the developing interest being shown in the Midcontinent Rift System as an hydrocarbon frontier by the American oil and gas industry. Overall 34 sub-sets of data were collected in the form of 12 profiles, oriented both across and sub-parallel to the central axis of the Midcontinent Rift System. The structural and stratigraphic interpretation of these profiles, as presented in this report, indicates that the consensus Lake Superior rift model, configured as a central horst enveloped by half-graben basins, is equally valid along the trend of the western arm of the Midcontinent Rift System, from the upper peninsula of Michigan south and west to southern Iowa.

This report is limited to the description and discussion of regional-scale structure and seismic stratigraphy, to encourage and stimulate additional analyses at detailed scale level. Such detailed evaluation is necessary to the better understanding of the Midcontinent Rift System, its past role in middle Proterozoic development of the Midwestern U.S., and its future significance in the determination of the economic geology potential of the Lake Superior basin.

HTML  interactive document (WOFR2002-02.htm)

Seismic sections are presented in three formats:

reduced scale for screen viewing (mini-plateXX.jpg),
full-scale JPEG (PlateXX.jpg), and
full-scale TIFF (PlateXX.tif).

May 8, 2002