Steven Dutch, Professor Emeritus, Natural and Applied Sciences, University of Wisconsin - Green Bay
The tectonically stable interval following the Penokean orogeny has been called the Baraboo Interval. Its later stages were characterized by widespread quartzite formation.
The quartzites consist of several areas of extensive cover, only gently deformed. The two largest are the Waterloo Quartzite in southeastern Wisconsin and the Barron in northwestern Wisconsin. The Barron may be equivalent to the sioux
Note also, beginning with this map, that the rift complex in northwestern Wisconsin has been peeled away. The underlying crust is probably an Archean greenstone-granite terrane similar to adjacent Archean rocks in Minnesota and Michigan. There are no data for these rocks in Wisconsin and the contacts shown are solely to simulate the map appearance of a typical greenstone-granite terrane.
Created 27 Dec 1997, Last Update 15 January 2020