Abstract: Is There A Gas-Containing Buried Impact Crater In The Catskill Mountains, New York?

Yngvar W. Isachsen, S. F. Wright, F. A. Revetta

Panther Mountain, located near the eastern edge of the Allegheny Plateau, is a circular mass, 10 km in diameter, defined by an anomalous annular drainage pattern. Pervasive fluvial cross-bedding in the terrigenous Devonian strata of the region make it impossible to determine whether the feature is slightly domal, slightly basinal, or unwarped. Joint density accounts for the greater erodability of the circular valley.

Gravity mapping shows a circular negative anomaly with a relief of 6 milligals. A north-south gravity profile across the anomaly is satisfied by a computed gravity profile of a shallowly buried (approx. 1 km) complex impact crater with a diameter of 10 km and an underlying brecciated and shattered rock zone 1 km thick. The modeled crater would extend through the Devonian section, and be a syndepositional structure. A greater joint density in the ring valley is ascribed to the influence of the crater rim on the geometry of sedimentation, and hence on the distribution of pores and other mechanical flaws. Elastic mismatches between rim and surroundings would also influence stress concentrations and hence joint formation. A very slight negative magnetic anomaly is consistent with the sign ficant (approx. 3 km) depth to basement. Regional, fracture-controlled linear valleys north and south of Panther Mountain terminate at the ring valley, perhaps due to absorption of stress by impact-associated brecciation. Seismic refraction studies also show that the Catskill region absorbs rather than transmits seismic waves.

The inferred impact crater beneath Panther Mountain would create a large potential reservoir for natural gas production, inasmuch as the structure intersects known gas producing formations in central and western New York. It would also provide a large reservoir for gas storage in proximity to New York City. Definitive testing of the impact hypothesis will require seismic reflection profiling and core drilling.

AAPG Search and Discovery Article #90986©1994 AAPG Annual Convention, Denver, Colorado, June 12-15, 1994