Southeastern Section - 68th Annual Meeting - 2019

Paper No. 41-18
Presentation Time: 1:00 PM-5:00 PM


FREELAND, Duncan L, Geology, Allegheny College, 520 N. Main St., Meadville, PA 16335 and TAMULONIS, Kathryn, Department of Geology, Allegheny College, 520 North Main Street, Meadville, PA 16335

The Upper Devonian Burket Formation is the basal black shale of the Genesee Group and extends throughout a portion of the basement-rooted Rome trough, a northeast-southwest trending segmented graben that initially formed during the Cambrian period. This structure has been reactivated throughout the Paleozoic, and few investigations have focused on Devonian shale stratigraphy within this structure. This study examines subsurface stratigraphic and thickness variations of the Burket Formation throughout the northern West Virginia segment of the Rome trough.

Burket Formation gamma, porosity, and density tracks were interpreted from seventeen wells in the study area, showing that the shale generally thins from approximately 60 feet to 20 feet to the southwest throughout the length of the trough. The formation is thickest in two zones: 1) the middle of the trough, and 2) to the east of the trough, and there is slight thinning along the trough margins. Thicknesses range between 10-30 feet in the western margin of the trough, 40-60 feet in the middle of the trough, and 20-30 feet along the eastern trough margin. The Burket well log signature changes drastically throughout the northeast-southwest oriented length of the trough and has the highest number of gamma-ray log ‘peaks’ in the northeast part of the study area. The number of high gamma-ray intervals in the Burket decreases from four in the northeast to one in the southwest part of the study area. The gamma ray log pattern also changes from east to west across the trough. Wells within the middle of the trough generally have more gamma peaks (2-3), while the wells outside of the trough to both the east and west have either one gamma ray peak or an interval with relatively higher gamma values (relative to overlying and underlying formations), but no distinct peak. It is hypothesized that a more complete stratigraphic record for the Burket Formation formed in parts of the trough with remnant subsidence and/or a mechanical predisposition for localized fracturing and subsidence, and areas with a less developed record may be indicative of sediment-starved regions.