The Midcontinent rift is a Middle Proterozoic continental rift which records about 15 m.y. of extension, subsidence, and voluminous volcanism in the period 1109-1094 Ma in the central part of North America. During that time the crust was nearly totally separated and as much as 25 km of subaerial basalts accumulated in a deep central depression. Following extension and volcanism, a longer period of subsidence resulted in development of a post-rift sedimentary basin in which as much a 8 km of fluvial and lacustrine clastic rocks were deposited. Partial inversion of the central depression occurred about 30-50 m.y. after extension to produce the current configuration of a central horst, composed mostly of thick volcanic accumulations, between shallower flanking basins. ?? 1992.
Citation Information
Publication Year | 1992 |
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Title | The Midcontinent rift in the Lake Superior region with emphasis on its geodynamic evolution |
Authors | W. F. Cannon |
Publication Type | Article |
Publication Subtype | Journal Article |
Series Title | Tectonophysics |
Index ID | 70016970 |
Record Source | USGS Publications Warehouse |