Shallow Oil in Northern Appalachian Basin: Evidence for Early Cretaceous Uplift from Fission Track Analysis
Ian R. Duddy, Donald S. Miller
Apatite fission track data from Devonian and Carboniferous sandstones of eastern New York and Pennsylvania (e.g., Catskills, Anthracite belt) imply rapid cooling, presumably associated with significant uplift, in the Early Cretaceous (about 135 Ma). Maximum burial temperatures are unknown; however, temperatures immediately prior to uplift were greater than 130°C, and limited zircon data suggest temperatures did not exceed 200°C. In western New York and Pennsylvania, the data are similarly consistent with abrupt Early Cretaceous cooling, but from maximum temperatures not exceeding 105°C.
New apatite data from subsurface samples from western New York allow us to calculate a minimum geothermal gradient of approximately 22°C/km, before the Early Cretaceous uplift. This calculation is compatible with shallow (200-600 m) Upper Devonian oil fields of the area, which have temperatures between 110° and 120°C in the Cretaceous, the Oriskany gas field at 140°C, Medina gas field at 150°C, and Trenton gas field at 170°C. These temperatures are compatible with oil- and gas-generation temperatures in other basins, and they provide a check for analysis. This minimum thermal gradient further implies that about 4 km of section must have been eroded from the region of these oil fields.
Thus, the fission track data suggest that oil fields between 200 and 600 m deep in the Upper Devonian sequences of southwestern New York and northeastern Pennsylvania contain fossil oil, which was generated prior to rapid cooling associated with significant regional uplift of the northern Appalachian basin during the Early Cretaceous.
AAPG Search and Discovery Article #91043©1986 AAPG Annual Convention, Atlanta, Georgia, June 15-18, 1986.