Revisiting geophysical interpretations of the Midcontinent Rift below Lake Superior— Insights from GLIMPCE seismic-reflection line C
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Abstract
The 1.1 Ga Midcontinent Rift System (MRS) has been investigated in the Lake Superior region for more than a century. The most influential geophysical data for modern paradigms has come from seismic-reflection profiles collected by the Great Lakes International Multidisciplinary Program on Crustal Evolution (GLIMPCE) in the late 1980s. We are revisiting seismic-reflection GLIMPCE line C by constructing a detailed velocity model for conversion of the seismic data measured in two-way travel time to a section plotted versus depth. Preliminary results from the velocity modeling, depth conversion, and ties to onshore geology have led to a significantly different view of Line C as primarily a sag basin rather than a half-graben. Narrow intervals of high-velocity material that emanate upwards along both sides of the sag basin are interpreted as mafic intrusions connected to the mantle. This new interpretation suggests that basin subsidence was the dominant process in the development of rift stage troughs rather than major half-graben structures.
Suggested Citation
Grauch, V.J., Heller, S.J., Woodruff, L.G., and Stewart, E.K., 2024, Revisiting geophysical interpretations of the Midcontinent Rift below Lake Superior— Insights from GLIMPCE seismic-reflection line C, in Institute on Lake Superior Geology: proceedings, Houghton, MI, May 15-18, 2024, p. 33-34.
Study Area
| Publication type | Conference Paper |
|---|---|
| Publication Subtype | Conference Paper |
| Title | Revisiting geophysical interpretations of the Midcontinent Rift below Lake Superior— Insights from GLIMPCE seismic-reflection line C |
| Year Published | 2024 |
| Language | English |
| Publisher | Institute on Lake Superior Geology |
| Contributing office(s) | Geology, Geophysics, and Geochemistry Science Center |
| Description | 2 p. |
| Larger Work Type | Book |
| Larger Work Subtype | Conference publication |
| Larger Work Title | Institute on Lake Superior Geology: proceedings |
| First page | 33 |
| Last page | 34 |
| Conference Title | 70th Annual Meeting, Institute on Lake Superior Geology |
| Conference Location | Houghton, MI |
| Conference Date | May 15-18, 2024 |
| Other Geospatial | Lake Superior |