Abstract

Erath County, Texas is located along the western margin of the Fort Worth basin which is a peripheral foreland basin surrounded by several regional sub-surface and surface structural features. These include the Muenster arch to the north, the Ouachita structural belt to the east and southeast, the Llano uplift to the south, and the Bend arch to the west. The Paleozoic Era in Erath County, Texas, is represented by Cambro-Ordovician, Mississippian, and Pennsylvanian age strata. The stratigraphic relationships and the structural and historical geology of the Paleozoic strata in Erath County, Texas, can be defined by plate tectonic theory.

Exploration has been predominantly centered in the northern portion of Erath County. Present production is from the Strawn sandstones, the Big Saline conglomerates, and the Marble Falls Limestone (Comyn Limestone) with potential production from the Ellenburger Dolomite. The most significant production thus far has been in the X-Ray (Marble Falls) Field from the Big Saline conglomerates. The present and future economic considerations of the Paleozoic strata apear promising due to the large amount of unexplored area in the southern portion of Erath County, the number of potentially productive horizons, the recent deregulation of oil and gas prices, and the fact that many of the producing fields are the result of the local development of porosity rather than structural entrapment.