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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 ...
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 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 ...
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 ]
Great Lakes tectonic zone; Great Valley Sequence – Group of late Mesozoic formations in the Central Valley of California; Hebridean terrane – Part of the Caledonian orogenic belt in northwest Scotland; Hottah terrane – Paleoproterozoic terrane in the northwestern end of the Canadian Shield
Minnesota is not a very tectonically active state but there is at least one fault zone in it, the Great Lakes Tectonic Zone, stretching from Big Stone County and Traverse County to Duluth. [2] Seventeen earthquakes have occurred along the fault, the two largest being the Morris quake and the Staples event of 1917.
From multicolored rock cliffs to towering sand dunes, there's no shortage of beauty all around the Great Lakes.
[5]: 32 The current boundary between these terranes is known as the Great Lakes tectonic zone (GLTZ). This zone is 50 km (30 mi) wide and extends in a line roughly 1,200 kilometers long from the middle of South Dakota, east through the middle of the Upper Peninsula of Michigan, into the Sudbury, Ontario region. The region remains slightly ...