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The North American Midcontinent rift beneath Lake Superior from GLIMPCE seismic reflection profiling

Tectonics

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Abstract

The Midcontinent rift system is a 1.1-b.y.-old structure extending from Kansas, through the Lake Superior region, and into southern Michigan. The rift is filled with thick sequences of basaltic volcanic rocks and clastic sediments. For most of its extent it is buried beneath Paleozoic rocks but can be traced by its strong gravity and magnetic anomalies. Seismic reflection surveys by the Great Lakes International Multidisciplinary Program on Crustal Evolution in 1986 imaged much of the deep structure of the rift beneath the lake in detail. The reflection profiles across the rift reveal a deep, asymmetrical central graben whose existence and magnitude was not previously documented. They show that, in addition to crustal sagging documented by previous investigations, normal faulting played a major role in subsidence of the axial region of the rift. The sense of asymmetry of the central graben changes along the trend of the rift, documenting the segmented nature of the structure and suggesting the existence of accommodation zones between the segments. -from Authors

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
The North American Midcontinent rift beneath Lake Superior from GLIMPCE seismic reflection profiling
Series title:
Tectonics
Volume
8
Issue:
2
Year Published:
1989
Language:
English
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
First page:
305
Last page:
332
Number of Pages:
28