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The epicenters show a clear relationship to tectonic features of the state; four epicenters lie along the Great Lakes tectonic zone. [15] Depths are estimated at 5 to 20 km (3 to 12 mi). [ 15 ] The best-documented event occurred on July 9, 1975, near Morris, Minnesota , with a magnitude of 4.6, and a felt area of 82,000 km 2 (32,000 sq mi ...
The next tectonic event was the Great Lakes tectonic zone which began with compression caused by the collision of the Superior province and the Minnesota River Valley subprovince during the Algoman orogeny about 2,700 million years ago; [5] it continued as a pulling apart (extensional) rift from 2,450 to 2,100 million years ago, [6]: 145 ...
It has been estimated that the foundational geology that created the conditions shaping the present day upper Great Lakes was laid from 1.1 to 1.2 billion years ago, [14] [55] when two previously fused tectonic plates split apart and created the Midcontinent Rift, which crossed the Great Lakes Tectonic Zone. A valley was formed providing a ...
The Algoman orogeny added landmass along a border from South Dakota to the Lake Huron region; this boundary is the Great Lakes tectonic zone (GLTZ). [ 5 ] Northeast Minnesota has 2700-million-year-ago exposed rocks formed during volcanic activity that was in the form of seepage of lava from rifts in the sea floor. [ 6 ]
This list covers all faults and fault-systems that are either geologically important [clarification needed] or connected to prominent seismic activity. [clarification needed] It is not intended to list every notable fault, but only major fault zones.
Volcanic strata protrude at Isle Royale and the Keweenaw Peninsula [9]. Lake Superior occupies a basin created by the rift. [3] Near the present lake, rocks produced by the rift can be seen on the surface of Isle Royale and the Keweenaw Peninsula of the Upper Peninsula of Michigan, [9] northwest Wisconsin, [10] and on the North Shore of Superior in Minnesota and Ontario. [4]
High temperatures on Tuesday will trend into the 20s and 30s F across the Great Lakes, Ohio Valley and New England. The pattern of lake-effect snow showers is set to persist through Tuesday ...
The Sudbury Basin is located near a number of other geological structures, including the Temagami Magnetic Anomaly, the Lake Wanapitei impact crater, the western end of the Ottawa-Bonnechere Graben, the Grenville Front Tectonic Zone and the eastern end of the Great Lakes Tectonic Zone, but the structures are not directly related to one another ...