Soils and Geology of Wisconsin Field Trip, October 9-11, 2009

Steven Dutch, Natural and Applied Sciences, University of Wisconsin - Green Bay
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Day 1: October 9, 2009

So How Many Cans of Sealant Ya Think We'll Need?

We're an hour into driving across the widest part of Wisconsin when we had a spot of trouble. We tried Wittenberg for a new tire with no luck so we limped into Antigo using the donut tire.  On the way the fall colors were close to peak.

Stop 1-1: Antigo Silt Plain

  Outstanding in his field, Professor Luczaj talks about the Antigo silt plain. Below left: To the north is the moraine of the Langlade Lobe. Below Right: To the east is the moraine of the Green Bay Lobe.

Stop 1-2: Irma Hill

Fall colors on State Route 64.
 
The Wisconsin River valley is ancient and deeply entrenched in Precambrian bedrock. Here we look across the valley. US Highway 51 crosses State Route 64 ahead.
Above: Professor Luczaj explains the geology. Below: on the outcrop.
Ripple marks in sandstone.
Glacial erratics presented a variety of rock types, including this rhyolite boulder.
One of the niftiest erratics is a boulder of staurolite schist. At left and below are closeups of the staurolite. At right below, the schist apperas to be a metaconglomerate.  
And the fall colors were great.
 
   

Ripplies, Believe It Or Not!

Just over the hill are a series of annual moraines prominently visible on aerial photos. They are best seen as a series of ripples looking down the road. They are believed to be the result of annual ice surges against the moraine. At right, below, one of the moraines rises behind the farmhouse.

Stop 1-3: Timms Hill

Didn't your mom ever warn you you could put your eye out with one of those?
At Timms Hill, highest point in Wisconsin. California has Mount Whitney. Maine has Mount Katahdin. Wisconsin has a bump on a moraine. People keep asking me in surprise when Timms Hill took the title from Rib Mountain. I have a road map dated 1972 that shows it. The Wisconsin Blue Book for 1962 lists Rib Mountain as the highest point, but the 1964 edition lists Timms Hill (spelled Tim's Hill)
Iron formation cobble in a wall.
The bench mark that marks the highest point in Wisconsin, all 1952 feet of it. Below: On top of the tower, which certainly gets you above 2000 feet.
 
And the fall colors were at their very best. Below: the highest hill is Pearson Hill, the second highest point in Wisconsin, only a foot or so below Timms Hill. So don't be surprised to see the title change hands, er, hills, next time the area is resurveyed.
Looking at the bench mark. The tower was there when I first visited Timms Hill in the mid '80's. I'm not sure if it's an old fire tower or if it's maintained for surveying, since it's exactly over the bench mark.
A gneiss boulder near the parking area.

Stop 1-4: Barron Quartzite

The Barron Hills on the skyline.Below: This quarry near Hardscrabble Ski Area is the easiest large exposure of quartzite. Like the Sioux Quartzite to the west, the Barron Quartzite is nearly horizontal, unlike the deformed Baraboo and Rib Mountain quartzites.
 

Making Camp

Day 2: October 10, 2009

No Extra Charge for This!

Well, this was a first. We're thinking of adding an "Adventure Camping" surcharge for exciting adventures like these.

Cambrian Basal Conglomerate

Wisconsin Potholes

   
Above: St. Croix Dells.Left: the lava 

Roughing It

Nobody felt much like cooking oatmeal in 20 degree cold.

The Deepest Potholes in the World

Osceola

A deep gorge in Osceola has an impressive waterfall in Cambrian sandstone. It must have hosted a very large falls during the ice age.

Stop 2-1: Grantsburg Moraine

Stop 2-2: Cambrian Outcrops in Hudson

Stop 2-3: Prescott

Along the Mississippi

Stop 2-4: Red Wing, Minnesota

Approaching the Mississippi River. The steep hill across the river is one of a series of isolated hills here.
Above: looking east toward the steep hill separating Red Wing from the Mississippi.Right: end view of the hill. Below: What explains these now dry, deep, broad valleys?
The most likely explanation for this landscape is that the channel of the Mississippi was diverted eastward by early Pleistocene ice. There are several channels so multiple diversions must have been involved.

Lake Pepin

Lake Pepin was dammed by the delta of the Chippewa River to the south. Lake Pepin was also the birthplace of water skiing. In 1922, Ralph Samuelson, after years of frustration in trying to find a lake on a hill, had an inspiration and smacked himself in the head with amazement. When he regained consciousness, he exclaimed "I should try using a boat!"

Stop 2-5: Chippewa River Delta

 The Chippewa River built a delta out into the Mississippi, crowding the river into a narrow channel on the Minnesota side and damming Lake Pepin.

On the way to Alma
 

Stop 2-6: Alma

 Alma, Wisconsin
A city park atop the bluffs offers exposures of the loess blanket and views of the river.
 Sampling the loess, which is at least 5 meters deep here.
Flagstones near the overlook have impressive trace fossils. Below: The overlook at Alma is spectacular.

From Alma to Trempealeau

   
 

Stop 2-7: Trempealeau Mountain

Trempealeau Mountain presents the same problems as Red Wing: what diverted the Mississippi to leave an isolated mountain? Except here the dry channel is on the east and we can't easily invoke ice diversion. The most likely scenario involves ice blocking the channel west of the mountain, cutting of a new channel to the east, then infilling of the eastern channel to re-divert the river to the west.
Above: views of the Minnesota bluffs.Left: Looking through Trempealeau toward Minnesota.

Camping in LaCrosse
   

Day 3: October 11, 2009

Stop 3-1: Grandad Bluff

Now that's precision dating! 
Panoramic views of the Mississippi from Grandad Bluff.
   
You don't often see topographic maps in neon lights.

Stop 3-2: Mindoro Cut

Stop 3-3: Seven Sisters

A highway stop of dubious legality and safety. The Seven Sisters are the chain of hills on the skyline. A ridge capped by Paririe du Chien dolomite, much like at the Mindoro Cut, breaks up into a series of dolomite capped hills. The last couple of hills have lost their cap.
A nearby rest stop describes the Driftless Area.

Stop 3-4 Necedah Mound

Shennington, a wide spot in the road, is home to these two picturesque churches.
View of Necedah Mound from the west.
Necedah Mound is made of quartzite. This locality is soon to be developed and the days of these outcrops are numbered.

Stop 3-5: Castle Rock

   The blocks used for landscaping appear to have come from the Glovers Bluff impact structure.

Ship Rock

 A favorite stop when traveling SR 21. Great sandstone and cementation structures.
 

Stop 3-6: Lake Wisconsin Shoreline

The outermost (westernmost) moraine of the Green Bay Lobe rises abruptly from the plain of Glacial Lake Wisconsin.

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Created 20 October 2008 , Last Update 13 January 2012

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