SEDIMENTOLOGICAL ANALYSIS OF HAMPSHIRE FORMATION CORES FROM RANDOLPH CO., WV

The Hampshire Formation is an Upper Devonian non-marine red bed unit in the central Appalachian basin of eastern WV. The Hampshire Formation in northern Randolph Co., WV, particularly along Route 33 near Elkins, along with correlative deposits in the subsurface of the Appalachian basin, have been characterized, but due to the limited outcrop exposures in the region, it has not been as thoroughly well studied toward the south. As a result, many aspects of Hampshire Formation stratigraphic correlation are unclear toward the southern part of WV. A total of 470 feet of core recovered from 7 vertical drill holes acquired for the construction of the Elkwater Fork Dam in southern Randolph Co. provide an opportunity to characterize the facies and interpret the sedimentology from unweathered rocks of the Hampshire Formation. Facies analysis of these cores reveal five primary lithofacies. Basal facies in the cores often consist of dark to light gray, fine-grained clay-rich mudstone with occasional reddish oxidized horizions. This facies exhibits range of sedimentary structures including flaser bedding, sub-horizontal laminations, and low-angle cross-laminations, with some intervals displaying burrows. Organic matter and plant fossils are locally present. The second lithofacies is composed of poorly sorted, medium- to coarse-grained, light gray to olive-colored sandstone with quartz granules and mudstone rip-up clasts that are often dark gray but also can be yellow or dark maroon. Crude horizontal laminations are present with low-angle laminations developed locally. The third lithofacies is composed of gray to whitish-colored, well sorted, fine- to medium-grained sandstone. Cross-laminations are common. The fourth lithofacies is red fine-grained clayey siltstone with mottled texture mixed with localized gray, medium-grained sandstone. Finally, the fifth lithofacies is composed of gray, medium-grained massive sandstone with centimeter-scale granule conglomeratic layers. Together these facies indicate deposition in a tidally-influenced delta or estuary. Geologic mapping in the vicinity of the Elkwater Fork Dam indicates these cores contain rocks of the Hampshire Formation, however, our findings indicate these facies are consistent with descriptions of the Cannon Hill Formation defined previously by other workers.