Analyses and descriptions of geochemical samples, Dolly Ann roadless area, Alleghany County, Virginia

Mineral resource potential map of the Dolly Ann Roadless Area, Alleghany County, Virginia

“…The rocks exposed in the Dolly Ann Roadless Area are chiefly marine clastic sedimentary rocks of Ordovician to Devonian age, which have an aggregate thickness of about 3,500 ft (1070 m) (table 1). The oldest formation present in outcrop is the Martinsburg Shale of Middle and Late Ordovician age, which is exposed in Dolly Ann Hollow and in, Falling Springs Creek valley just north of the study area (Lesure, 1981). An overlying sequence of resistant sandstone and quartzite beds interlayered with shale, ranging in age from Late Ordovician to Middle Silurian, includes the Juniata Formation, Tuscarora Quartzite, Rose Hill Formation, and Keefer Sandstone, which form the bedrock in most of the study area.…”

“…Much of the area is Grayish-red sandstone and shale; some mediumgray to greenish-gray sandstone and shale in the east Dark-gray calcareous shale and thin-bedded argillaceous limestone; some interbedded coarse crystalline limestone ' covered by a series of landslide masses and by colluvial material consisting of boulders and cobbles of red and white sandstone from the Lower and Middle Silurian formations. This debris conceals the bedrock of large parts of the study area, especially where the Upper Silurian and Lower Devonian formations would otherwise be exposed (Lesure, 1981).…”

“…The grade of the hematitic sandstone ranges widely from 10 to 28 percent iron, but a weighted average for all samples is about 18 percent iron (Lesure, 1982;Jones and others, 1982, p. 19) which compares well with data on similar rock from Giles County, Va. (Fish, 1967, p. 10;Lesure and others, in press). Using the geologic map of the Dolly Ann area (Lesure, 1981), we can estimate • that 8 the Rose Hill is exposed in about 2,700 acres (1,090 ha), is covered by 5-200 ft (1.5-60 m) .Pf younger rock in 2,800 acres {1,130 118}, and is .covered by more than 200 ft (60 m) in 1,~00 acres (530 ha) (fig. 4).…”