GROUND WATER IN NORTH-CENTRAL TENNESSEE
GROUND WATER IN NORTH-CENTRAL TENNESSEE
GROUND WATER IN NORTH-CENTRAL TENNESSEE
Create successful ePaper yourself
Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.
66 <strong>GROUND</strong> <strong>WATER</strong> <strong>IN</strong> <strong>NORTH</strong>-<strong>CENTRAL</strong> <strong>TENNESSEE</strong><br />
are complexly folded and faulted in a manner that is unique for<br />
central Tennessee. The area of deformation covers a roughly cir<br />
cular area about 8 miles in diameter, and the strata involved range<br />
from the limestone of Beekmantown (?) (earliest Ordovician) age to<br />
the St. Louis limestone. This structural feature is known as the<br />
Wells Creek uplift, from the name of the stream that drains most of<br />
the area of deformation. Its relation to the forces that caused the<br />
upwarping of the Nashville dome and the formation of its superposed<br />
secondary folds is unknown. However, it is possible that crustal<br />
warping began in the Wells Creek area quite as early as in the Nash<br />
ville Basin, for the Wells Creek section may lack the entire Stones<br />
River group, of Lower Ordovician age (pp. 57-58), and lacks much<br />
of the Middle Ordovician and Upper Ordovician (Richmond) group.<br />
The unique structure of the Wells Creek uplift was first recognized<br />
by Safford,35 who pointed out that the strata in the center of the de<br />
formed area are older than any other rocks exposed in central Ten<br />
nessee and that they dip vertically or at high angles. Safford inter<br />
preted the structural feature as a high dome, with the strata cropping<br />
out in successive bands concentric about the apex of the dome and<br />
dipping away from the center of the basin. He also pointed out<br />
that the Mississippian rocks are both folded and faulted for several<br />
miles away from the area of intense deformation, as is exposed in<br />
the bluffs of the Cumberland River several miles upstream and<br />
downstream from Cumberland City.<br />
Jillson 36 has pointed out certain similarities of the structure of the<br />
Wells Creek uplift to that of Jeptha Knob, in Shelby County, Ky,,<br />
and Serpent Mound, in Adams County, Ohio. He assumes that all<br />
these features are contemporaneous and concludes that they were<br />
produced by forces transmitted by a body of igneous magma a few<br />
thousand feet beneath the surface.<br />
Very recently Bucher has started to map the structure of the<br />
Wells Creek uplift in detail. His prelimininary report 37 is abstracted<br />
in the following paragraphs:<br />
Topographically the Wells Creek Basin is an elliptical depression<br />
in the Highland Rim plateau (pp. 16-18) bounded on all sides by an<br />
erosion scarp 225 to 275 feet high. This depression is about 2% miles<br />
long and 2 miles wide, and the longer axis trends nearly due north.<br />
The floor of the basin comprises three topographic units, which are<br />
also stratigraphic and structural units. These are a central hill,<br />
which is rudely circular, 2,700 feet in diameter, and about 80 feet<br />
high; a ringlike lowland plain 1,500 to 3,500 feet wide surrounding<br />
the central hill; and a belt of foothills 1,500 to 2,000 feet wide sur-<br />
» Safford, J. M., Geology of Tennessee, pp. 147-148, Nashville, 1869.<br />
» Jillson, W. B., An isothrustic hypothesis: Fan Am. Geologist, vol. 40, pp. 251-268,1923.<br />
w Bucher, W. H., The stratigraphy, structure, and origin of Wells Creek Basin, Tennessee: Tennessee<br />
Dept. Education Div. Geology (in preparation).