ABSTRACT
About 14,000 ft (4,270 m) of strata covered basement over the present crest of the Nashville dome by the end of the Paleozoic (calculated by estimating the geothermal gradient, and using temperatures of veins in Stones River Group and Knox Dolomite). At least 7,500 ft (2,290 m) of post-Devonian strata have been removed by subsequent erosion. Estimates of other erosional episodes include 350 ft (107 m) of upper Knox (during the Middle Ordovician) and 500 ft (152 m) of Devonian-Ordovician (during the Late Devonian). Mesozoic to Holocene uplift was at least 6,350 ft (1,940 m), 1,500 ft or 460 m (25%) of which occurred in the latest 100 m.y. and 450 ft or 140 m (7%) during the latest 2 m.y., a rate ranging from about 15 ft/m.y. (4.6 m/m.y.) for the longer term to over 225 ft/m.y. (70 m/m.y.) in the Pleistocene to Holocene.
Earliest structure of the area was a series of elongate basins, probably rifts synchronous with Reelfoot rift to the west. Uplifts trending N10°E moved about 40 mi (65 km) westward during the Middle Ordovician. These may relate to similar trending (and moving) Appalachian orogenic events. A change to uplifts trending N50°E (parallel to strikes of Appalachian thrusts) occurred in the Late Ordovician and continued to the Devonian; this may reflect a similar Late Ordovician change in the orientation of Appalachian tectonism. In the interval from post-Mississippian to Late Cretaceous, the dome curved westward to join the Pascola arch in response to Ouachita activity.