Search results
Results from the WOW.Com Content Network
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 ]
These plates, called tectonic plates, can push against each other. Earthquakes are most common along fault lines, which are fractures that allow the plates to move.
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
Home & Garden. Medicare. News
It was during the Penokean orogeny, part of the process that created the Great Lakes tectonic zone, that many valuable metals were deposited. The region surrounding the lake has proved to be rich in minerals, with copper , iron , silver , gold and nickel the most frequently mined.