The Trenton Limestone of Northwestern Ohio: An Analogue for Deeper Exploration
Wickstrom, Lawrence H.1 and T. Joshua Stark2
1 Ohio Division of Geological Survey, Columbus, OH
2 XTO Energy, Fort Worth, TX
The Lima-Indiana oil and gas trend, which was extensively developed in the late 1800s and early 1900s, extends in a broad curve for 185 miles from Toledo, Ohio, southwestward to Indianapolis, Indiana. The principal reservoir rock throughout this trend is the Ordovician Trenton / Black River Limestone. To the southeast of the Lima-Indiana trend, NW-SE oriented linear hydrothermal dolomite fields have been discovered, producing sporadically in Ohio from about 1930 to the present day. Collectively, these fields have produced in excess of 500 million barrels of oil and well over 1 trillion cubic feet of natural gas. It is therefore no surprise that operators are continually drawn back to this area in search of additional reserves.
Most of the structural elements of this area can be shown to have their roots in the underlying Proterozoic Keewanawan and Grenvillian crystalline terrains. Often these features exhibit multiple episodes of structural reactivation and mineralization beginning in the Cambrian and extending to post Silurian time. Two important tectonic episodes central to the creation of the reservoirs and traps of this system were the late Cambrian-early Ordovician passive margin regime and the mid-to-late Ordovician compressional events of the Taconic Orogeny. The different styles of faulting, rotation, relative uplift and subsidence from these two major episodes resulted in depositional patterns that controlled thickness and facies distributions. Remobilization tectonism also augmented basement regional faults, providing the conduits for the creation of reservoirs and migration of hydrocarbons. This vast productive area may yet contain additional large reservoirs and provides an analogue for the more deeply buried Trenton/Black River targets sought across a broad sweep of the eastern mid-continent.
AAPG Search and Discovery Article #90031©2004 AAPG Eastern Section Meeting, Columbus, Ohio, October 3-5, 2004