(1) Innova Exploration, Inc, Traverse City, MI
ABSTRACT: Structural Styles of Hydrothermal Dolomite Reservoirs in the Michigan Basin
The major hydrothermal dolomite reservoirs in the Michigan Basin include the well known
Trenton-Black River (Ordovician) fields; Albion-Scipio (125 MMBO and 205 BCF),Stoney Point
(17 MMBO and 19 BCF), and Northville (1 MMBO and 13 BCF) in Michigan as well as numerous
fields in Ontario such as Romney 6-13- III& IV (2.6 MMBO and 1 BCF). There are also
significant hydrothermal dolomite reservoirs however in the Dundee (Devonian) which
include the Deep River (27 MMBO), North Adams (9 MMBO) and Pinconning (1MMBO) Fields. The
above reservoirs are controlled by strike slip fault systems. The episodic movement of
these fault systems during the various Appalachian orogenic events provided the necessary
vertical conduits for the upward migration of the hot, saline dolomitizing fluids.
Numerous experimental models and in-nature examples show that early stages of strike slip faulting produce a series of en-echelon Reidel shear faults, commonly with a helicoidal geometry, from a single fault at depth. In cross section, the Reidel shear faults with compression (transpression) produce positive flower structures whereas Reidel shear faults with extension (transtension) produce negative flower structures. Seismic profiles of the above cited hydrothermal dolomite reservoirs in the Michigan Basin illustrate both transpression (positive flower structures) and transtension (negative flower structures) structural styles. It is my contention that seismic profiles of some of these fields previously described as “sags” or “grabens” are in fact negative flower structures and are a manifestation of strike slip faulting, not collapse due to dissolution or that misconstrued concept of dolomite shrinkage.
AAPG Search and Discovery Article #90026©2004 AAPG Annual Meeting, Dallas, Texas, April 18-21, 2004.