NASHVILLE DOME

southward geologic extension of the Cincinnati Arch (q.v.) that is prominent in Tennessee. Ordovician rocks (about 505 to 438 million years in age) constitute the oldest strata exposed in the core of the dome; they are surrounded by Carboniferous strata (roughly 360 to 286 million years old). The dome was submerged at various times, while during others the central portions were elevated above sea level and exposed to erosion. Two major uplifts affected the Nashville Dome. The first occurred in Late Devonian time (374 to 360 million years ago); considerable erosion occurred, and some 150 m (500 feet) of deposits were removed. The second major tectonic event took place in the Carboniferous Period, when extensive erosion again occurred.