STRATIGRAPHY OF THE MIDDLE DEVONIAN HAMILTON GROUP, NICHOLAS COUNTY, WEST VIRGINIA

The Middle Devonian Hamilton Group in Nicholas County, WV, comprises a 45 to 58 foot thick interval of terrigenous sediment between the Onondaga and Tully limestones. These sediments are identified as the Mahantango Formation and the Marcellus Shale. The Marcellus Shale ranges in thickness between 38 and 48 feet. The organic-rich shale can be subdivided into two units. The lower unit thins to the southwest as it onlaps the Onondaga Limestone. The upper unit also thins to the southwest but due to erosion by the Taghanic unconformity. The Mahantango Formation ranges from 10 to zero feet thick. Thinning is due, in part, to stratigraphic convergence but is also to post-depositional erosion. The overlying Tully Limestone is also truncated by the Taghanic unconformity.

A cluster of wells produce gas from the Marcellus Shale in eastern Nicholas County. Most have been abandoned because of low production and/or poor development.