Analysis of seismic reflection data over the Sanford Triassic Basin, Chatham and Lee Counties, North Carolina

Abstract

Approximately 9.5 km of seismic reflection data over the western margin of the Sanford Triassic Basin in North Carolina were acquired by Chevron, Inc. in 1972. These data enabled a comparison of the relative effectiveness of dynamite and vibroseis sources to be made. A comparison of 3-fold and 12-fold dynamite data, as well as 24-fold vibroseis data with a relatively limited bandwidth, indicate that frequency content of the source used in seismic surveys over Triassic basins is more critical in determining the quality of the stacked data than subsurface coverage. The use of an automatic line drawing routine proved useful in delineating the subsurface geometry of the basin. Available well data were used in conjunction with the seismic data to locate the Cumnock (coal-bearing) Formation within the basin and construct a geologic section across the study area. Strong reflections from the bottom of the basin were recorded. Reflections from beneath the basin ( > 0.7 sec) are attributed to meta volcanics and mylonites of the Carolina Slate Belt.