Odyssey Through Orogeny: Geosci 655 – Wisconsin Tectonics

Dyanna Czeck and her “Wisconsin Tectonics” class (Geosci 655) went on an “Odyssey through Orogeny” fieldtrip to Michigan’s UP and northern Wisconsin on Oct 9-11, 2015. They started by investigating the shores of Lake Superior in Marquette, Michigan where they saw rocks from the Archean Ishpeming Greenstone belt, crossed south through the Great Lakes Tectonic Zone to see Archean gneisses, and studied the unconformably overlying Paleoproterozoic Marquette Supergroup that was folded in the Penokean Orogen… and the even younger Keewenawan Jacobsville Sandstones were unconformably overlying everything along the Lake Superior exposures! Whew! Lots of geology in a compact area!

  • Investigating cross-cutting relationships at Lighthouse Point in Marquette, MI
    Investigating cross-cutting relationships at Lighthouse Point in Marquette, MI

On route further south, they investigated the strange metamorphic zones around Republic, Michigan before they headed south to the lovely mylonites of the Niagara Fault Zone. Next, they crossed back into Wisconsin to the arc rocks of the Pembine-Wausau Terrane until they arrived at the Eau Pleine shear zone which is the suture zone with the next terrane to the south, the Archean Marshfield Gneiss Terrane. After a quick stop in Steven’s Point to spend some time on the exotic Marshfield microcontinent, they headed back to Milwaukee.

Everyone had a different favorite outcrop, but some highlights were the beautifully folded banded iron formation at Jasper Knob in Ishpeming and some very bizarre looking weathered peridotites overlain by Jacobsville Sandstones at Presque Isle Park in Marquette.

Some of the group even took a nap on some deformed greenstone belt pillows. The weather was fabulous (70 degrees along Lake Superior!), the fall colors were magnificent, and the geology was fascinating. All together, this made for a great trip with a spectacularly pleasant group of individuals! Undergraduate students attending the trip were Rick Bartz, Detaya Johnson, and Andrew Ladousa. Graduate students attending the trip were Fatimah Abuduwufu, Megan Barlow, Kyungdoe Han, Ken Oanes, and Kate Pauls.