Day #111 Deskcrop: Mylonite, Eau Pleine Shear Zone

The Eau Pleine Shear Zone marks the boundary between the Archean Marshfield Terrane and the Proterozoic Wausau-Pembine Terrane in central Wisconsin. Today’s deskcrop is a mylonite from the Eau Pleine Shear Zone. I have only the vaguest recollection of the actual locality where this rock was collected, and it’s entirely possible I’ve badly mislocated the quarry from which it was retrieved, but the quarry near Dancy, WI where I’ve located the placemark is within the mapped boundaries of the EPSZ and seems plausible based on my weak recollection of the particular field excursion when I collected this deskcrop. I really need to spend a couple of weeks reacquainting myself with Wisconsin’s outcrops…

Mylonite, Eau Pleine Shear Zone

Explore this and all of my 2010 Deskcrops and Outcrops in Google Earth!