and Granite Peak Ski area http://en.wikipedia.org/wiki/Granite_Peak_Ski_Area
What really got to me was the reception place was called Granite Peak but when I looked at the rocks expecting to see granite all I saw was quartzite. I did not get a sample because I was dressed up and didn't have a purse with me and no place to store it. I closeup of the one rock I tried to take was too blurry to post. Oh well - at least I got some wonder other photos.
It was a fun reception and different. We were allowed to ride the ski lift. Even though there was no snow on the ground it was and incredibly beautiful ride and one you won't forget doing.
Look and see for yourself.
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| Rib Mountain ski lifts during the fall |
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| fall foliage on Rib Mountain |
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| View of Wausau Wisconsin from Rib Mountain |
We had such a good time and I was so happy that my niece has found someone to be with.
As to the geology of the area from what I can tell - because there was so much quartzite - It probably was a beach area with a lot of sandstone. The sandstone was pretty pure with not a lot of other stuff in it - it may have been aeolian dunes? that then later got metamorphized. I could tell it was a quartzite because of the way it would fracture through the quartz and not around the grains like a well cemented sandstone would normally be. Here's what Wikipedia has to say about quartzite http://en.wikipedia.org/wiki/Quartzite .
PS I've finally been able to come back to this post and give a little insight into the rocks.
I have the" Roadside Geology of Wisconsin" book by Roberty H Dott and John W. Attig (2004) pgs 59-68.
These rocks should be PreCambrian in age. The best I can tell they are part of the Wolf River Igneous Complex.
As it says in its name its complex. Here's quoting from Dott & Attig pg 61- 63.
'Approximately 12 miles north of Stevens Point at the Portage-Marathon County boarder (mile 171.5 -Interstate hwy 39/US51) the highway crosses a major boundary between the Marshfield continent and the Peokean belt. It is concealed along the highway, but in scattered exposures to the west along the Big Eau Pleine River a zone of intense shearing marks the fault zone suture between these provinces. The faulted boundary is traceable from a little east of I-39 for 100 miles Northwest, where it disappears beneath flat-lying Cambrian Strata. North of the boundary, Archean rocks are absent and Peolean volcanic and granitic rocks predominate. Regardless of where the Marshfield Archean rocks originated, they must have been close to their present position during the Peokean episode for them to have been intruded by various Penokean-age igneous rocks around 1,850 to 1830 million years ago. At Mosinee, Peokean granitic and other igneous rocks are exposed. "
On page 6-9 this is what they have to say about Precambrian WI at about this time. "Beginning about 1,900 million years ago, everything changed when a volcanic island chain loomed out of the sea across central Wisconsin and erupted volcanic rocks. the surrounding sea was deeper than earlier seas- the remaining sediments are characteristic of deep water. The seafloor south of the early continent deepened as it was subducted and the island chain moved northward, finally colliding with the margin of the old Superior continent to form the Penokean Mountains, Wisconsin's "Rocky Mountains" Granites that were intruded widely during this collision yield dated from 1890 to 1815 million years. Geologist have traced the roots of those old mountain from Michigan across Wisconsin at least as far west as Minnesota, and they represent a major addition to the Superior continent.
Nature was not though mangling Wisconsin. for less than 100 million years later, a new heating event produced more granite and the eruption of much rhyolitic volcanic material across the southern half of the state. When calm returned, a thick succession of red sandstones, black shale's and another banded iron formation were deposited across Wisconsin and Minnesota. There in turn were crumpled and metamorphosed around 1650 million years ago. And 200 million years later a large granitic complex called the Wold River Batholith was intruded in east-centeral Wisconsin.
The final Precambrian episode involved a very different behavior of the earth's crust across northwestern Wisconsin and adjacent Minnesota. Continental rifting there, called Lake Superior rift, threaten to tear North America in half, causing the two halves to drift apart. This crisis began with the eruption of enormous volumes of basaltic lavas along a great depression in norther Wisconsin and adjacent Minnesota around 1100 million year ago. after the eruption ceased, subsidence of the ruptured crust continued for at least 200 to 300 million years, and thick red conglomerates, sandstones, and shales were deposited within the rift. Hot solutions percolating through the basaltic lava rocks and overlying conglomerate deposited much pure copper, which was the basis for an important copper mining industry, especially in northern Michigan, for more than a century. This was the source for pieces of copper that Quaternary glaciers carried into Wisconsin hundreds of million of years later."
From what I observed these rocks should be the ones where there was rifting occurring and the granitic material intruded into the basaltic rocks. As you can tell its very complex and I didn't have enough time to really look at and figure this out all on my own.
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Geologic maps of Wisconsin and some information on the Wolf River Igneous Complex.
http://wisconsingeologicalsurvey.org/pdfs/pgszpdf/bedrock_geology.pdf
http://tin.er.usgs.gov/geology/state/sgmc-unit.php?unit=WIYhp%3B0
