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Taylors Falls in Chisago County, Minnesota — The American Midwest (Upper Plains)
 

Geology of the Taylors Falls Region

 
 
Geology of the Taylors Falls Region Marker image. Click for full size.
By K. Linzmeier, July 23, 2011
1. Geology of the Taylors Falls Region Marker
[rain drops are on the marker]
Inscription. About 1.1 billion years ago, a great rift valley formed across the North American continent from the Lake Superior region southwest to Kansas. As this rift valley opened, basaltic lavas erupted into it, accumulating to a thickness of up to 20 kilometers in the Lake Superior region. The dark-grey basalt rock that form the St. Croix River gorge are made from these rift lava flows. Continental rifting with volcanism is common in the geological record and often leads to the breakup of continents and the formation of intervening ocean basins. For reasons not completely understood, the Midcontinent Rift here in North America failed to evolve to the stage of complete continental separation.

About 520 million years ago in the Lake Cambrian period, the North American continent was positioned with Minnesota near the equator. Shallow seas covered the region, into which great thicknesses of mainly quartz sand were deposited. These deposits are now the sandstone bluffs along this river valley and the rock faces exposed on the highway road cuts south of this marker. Although most of the region then lay flat, the basalts in the Taylor Falls area stood high as rocky, cliff-ringed islands in a tropical sea.

The most recent geological event recorded here occurred about 12,000 years ago during the end of the Ice Age of the last two
Geology of the Taylors Falls Region Marker image. Click for full size.
By K. Linzmeier, July 23, 2011
2. Geology of the Taylors Falls Region Marker
million years. As the last of the glaciers melted and receded to the north, tremendous quantities of sediment-laden glacial meltwaters were channeled into the St. Croix River valley. Here at Taylor Falls, a colossal torrent of abrasive currents carved down through the Cambrian sandstones and deep into the rift basalts now seen on the valley floor. The spectacular potholes in the lava rock, found in Interstate Park about 0.4 kilometers north of this site, attest to the high velocity of the raging glacial waters that carved the St. Croix River gorge.

Erected by the Geological Society of Minnesota in partnership with the Minnesota Department of Transportation and the Minnesota Geological Survey 1998
 
Erected 1998 by the Geological Society of Minnesota in partnership with the Minnesota Department of Transportation and the Minnesota Geological Survey.
 
Location. 45° 23.866′ N, 92° 39.315′ W. Marker is in Taylors Falls, Minnesota, in Chisago County. Marker is on Saint Croix Trail (U.S. 8) 0.3 miles south of Bench Street (State Highway 95), on the left when traveling south. Click for map. Marker is in Interstate State Park at the Taylors Falls Scenic Overlook; no nearby parking is available. Marker is in this post office area: Taylors Falls MN 55084, United States of America.
 
Other nearby markers.
St. Croix River and Marker image. Click for full size.
By K. Linzmeier, July 23, 2011
3. St. Croix River and Marker
At least 8 other markers are within 2 miles of this marker, measured as the crow flies. Taylors Falls United Methodist Church (approx. 0.2 miles away); Folsom House (approx. 0.2 miles away); Glacial Potholes (approx. 0.2 miles away); Town House School (approx. mile away); Chisago Hotel (approx. 0.3 miles away); Interstate Park Centennial (approx. half a mile away in Wisconsin); State Park Movement in Wisconsin (approx. 0.6 miles away in Wisconsin); Where Are The Falls of the St. Croix? (approx. 1.1 miles away in Wisconsin). Click for a list of all markers in Taylors Falls.
 
Also see . . .
1. Minnesota Department of Natural Resources. Geology of Interstate Park; The St. Croix Dalles, home of the World's Deepest Potholes. (Submitted on August 8, 2011.) 

2. Minnesota Department of Natural Resources. Interstate State Park. (Submitted on August 8, 2011.) 
 
Categories. Natural Features
 
St. Croix River image. Click for full size.
By K. Linzmeier, July 23, 2011
4. St. Croix River
U.S. Highway 8 image. Click for full size.
By K. Linzmeier, July 23, 2011
5. U.S. Highway 8
The marker is to the right of the rock face.
Glacial Pothole image. Click for full size.
By K. Linzmeier, June 11, 2011
6. Glacial Pothole
As noted on the marker, one of the many potholes at Interstate Park.
 
 
Credits. This page originally submitted on , by Keith L of Wisconsin Rapids, Wisconsin. This page has been viewed 715 times since then and 24 times this year. Photos:   1, 2, 3, 4, 5, 6. submitted on , by Keith L of Wisconsin Rapids, Wisconsin. This page was last revised on June 16, 2016.
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