Paleogeography and Dundee Production in Central Michigan: Controls and Influences

J. R. Myles
Scot Energy, Acme, MI

The distribution of the various types of Dundee Limestone reservoirs across central Michigan reflects the progression of depositional influences from a western lagoon, across an intervening shoal, and into an eastern open marine shelf. An isopach between the base of the Rogers City Limestone and the Detroit River Anhydrite is a useful tool for understanding the Dundee Limestone paleogeography. The dolomitized Rogers City Limestone reservoirs, characterized by efficient water-drives, are found atop the isopach “thicks” (shoal area), east of the depositional edge of the Reed City Anhydrite (lagoonal facies).

The location of the Dundee shoal to the east of the Ordovician gas-producing structures in Osceola, Newaygo, Mecosta and Montcalm Counties suggests the possibility of deeper basinal influences on Dundee paleogeography.A Precambrian continental suture trends southwest to northeast across central Michigan, bringing together basement terranes with differing styles of deformation. The Osceola to Montcalm Ordovician gas production lies north of the suture, and the productive trend is subdivided by rift-related transfer faults into half-graben arrangements of drape-fold closures overlying tilted basement blocks. Each half-graben has its distinctive dip-slope orientation. The Dundee shoal has developed over the hingelines of halfgrabens whose bounding faults dip to the northeast.

The Dundee fracture porosity fields near Saginaw Bay overlie the continental suture. Subtle wrenching accompanying reactivation of basement faults by late Paleozoic compression is believed to be responsible for the development of these prolific reservoirs.

AAPG Search and Discovery Article #90900©2001 AAPG Eastern Section Meeting, Kalamazoo, Michigan