THE TECTONIC CONTEXT FOR THE GOGEBIC RANGE IRON FORMATIONS

To determine the tectonic context and identify key factors driving iron formation deposition after the Great Oxidation Event, we apply a stratigraphic facies approach and present updated mapping relationships of the Ironwood Iron Formation and the Emperor Volcanics from the Gogebic range. This work is coupled with a compilation of additional outcrops, mine data and core logs. We interpret the datasets to demonstrate that later deformation does not explain the observed thickness changes, but that instead they are consistent with depositional complexities spanning the entire Gogebic range. Our results quantitatively constrain thickness variations along the Gogebic range and tie them to syn-sedimentary faulting along normal faults and half grabens.