A Time-Transgressive Model for the Burnt Bluff Group: New Insights from Outcrop and Subsurface Samples
Previous work has shown that the Burnt Bluff Group was deposited as a series of shallow to moderate water depth facies in a tropical marine setting in the Michigan Basin during the lower Silurian. New interest in the unit for both hydrocarbon resources (subsurface) and aggregate resources (outcrop) are driving research in a poorly understood unit in the Michigan Basin. Additional cores as well as investigation of the outcrop belt in the Upper Peninsula has allowed us to refine the model further.
The traditional view of the Burnt Bluff Group consists, in stratigraphic order, of the open-marine Lime Island Formation, the restricted lagoon-tidal flat Byron Formation and the open-marine Hendricks Formation. The contacts with the underlying Cataract Group and overlying Manistique Group are transitional with the Burnt Bluff Group. Identification and description of facies in both cored material and outcrop sections provided new constraints on the Burnt Bluff Group. Outcrop data has forced the revision of the depositional model for the unit as typical Byron-like facies are found interbedded with Hendricks-like facies.
Limited age date from published research combined with the new facies model for the Burnt Bluff Group suggests that the unit was deposited as a time-transgressive package on a carbonate ramp during the Lower Silurian.
AAPG Datapages/Search and Discovery Article #90218 © 2015 Eastern Section Meeting, Indianapolis, Indiana, September 20-22, 2015