Geology of the Damascus area

Abstract

Marine sedimentary rocks ranging in age from Early Cambrian(?) to Middle Ordovician, inclusive, crop out in the Damascus area. Approximately 13,000 feet of beds are exposed, comprising 14 formations. The stratigraphic succession is rather complete and is broken by a single recognizable hiatus which represents most of late Early Ordovician time. Clastic rocks of questionable Early Cambrian age are about 3,600 feet thick. Rocks of known Cambrian age are about 6,800 feet thick and consist of, in ascending order, elastic rocks, dolomite, shale and carbonate rocks, and mixed carbonate rocks. Carbonate rocks of Early Orodovician age range from 1,000 to 6,000 feet in thickness. Middle Ordovician rocks aggregate approximately 800 feet in thickness, the basal 100 feet of which is limestone and the remainder is shale and sandstone. The Elbrook formation of middle and Late Cambrian age is herein divided into four members of which one, the Widener limestone member, is formally named and mapped. A crepicephalus fauna from the Widener limestone, and a single trilobite, Plethometopus sp. From the Conococheague formation are illustrated. The strata have been folded into five synclines and four anticlines and are broken by two major thrust faults, and Lodi thrust and the Holston Mountain thrust. The faults were initially low-angle thrusts which have been folded with the overridden rocks so that locally the fault planes have steep dips.