Age and tectonic significance of the Grizzly Creek Shear Zone, western Colorado

In the summer of 2006, undergraduate students Bobby Goodfellow (Geology) and Megan Mekoli (Chemistry) spent a week in western Colorado with UMM geology faculty member Jamey Jones mapping the Grizzly Creek Shear Zone (GCSZ) and collecting samples for U-Pb geochronology. The GCSZ is a ~1 km thick zone of intense deformation that formed deep in the Earth's crust (~15 km?) between 1.7-1.4 billion years ago (Ga, or Giga annum). It has been brought to the surface by more recent tectonism in the Rocky Mountain, and Bobby, Megan, and Jamey are working with faculty and students from Concord University and Montana State University to try and determine the age of deformation and the regional significance of the shear zone. Bobby's and Megan's research was funded by the University of Minnesota Undergraduate Research Opportunities Program (UROP).