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The Midcontinent Rift System (MRS) or Keweenawan Rift is a 2,000 km (1,200 mi) long geological rift in the center of the North American continent and south-central part of the North American plate. It formed when the continent's core, the North American craton , began to split apart during the Mesoproterozoic era of the Precambrian , about 1.1 ...
[4]: 7 This zone of crustal thinning and fracturing is the Midcontinent Rift System; it extends in a boomerang shape for over 2,200 km (1,400 mi) from northeastern Kansas northward through Iowa, under the Twin Cities of Minnesota, beneath Lake Superior, and then south through the eastern Upper Peninsula of Michigan and beneath the central Lower ...
The Humboldt Fault (red) and Midcontinent Rift System (green) in Kansas and Nebraska. The Humboldt Fault or Humboldt Fault Zone, is a normal fault or series of faults, that extends from Nebraska southwestwardly through most of Kansas. [1] Kansas is not particularly earthquake prone, ranking 45th out of 50 states by damage caused. [2]
The Keweenawan Supergroup is a supergroup of volcanic and sedimentary rocks that fill the Midcontinent Rift System in the U.S. states of Michigan, Wisconsin, and Minnesota. [1] [2] It is about 30 kilometers (19 mi) thick and it formed about 1.1 billion years ago. [3]
One billion years ago, the Midcontinent Rift System began to extend along a 2,000 kilometres (1,200 mi) path, [10] across both the Canadian Shield and the Stable Platform. The rift failed, then crustal movement reversed. A range formed then eroded, forming basins on either side of a horst.
Over 1,100 mya, a rift formed and lava emerged from cracks along the edges of the rift valley. This Midcontinent Rift System extended from the lower peninsula of Michigan north to the current Lake Superior, southwest through the lake to the Duluth area, and south through eastern Minnesota down into what is now Kansas. [5]
The Stenian period Midcontinent Rift System that is still visible at the surface in the area of Lake Superior. The Mississippi embayment with the associated New Madrid Seismic Zone is an example of an ancient aulacogen that dates back to the breakup of the ancient continent, Rodinia.
The West and Central African Rift System; The Red Sea Rift; The Gulf of California; The Baikal Rift Zone, the bottom of Lake Baikal is the deepest continental rift on the earth. The Gulf of Suez Rift; Throughout the Basin and Range Province in North America; The Rio Grande Rift in the southwestern US; The rift zone that contains the Gulf of ...