Town Knobs Fault EarthCache
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The fault is located on the north side of Hwy 11-W
approximately 2 miles west of Rogersville. Park on the side of
highway. Exercise caution due to fast moving traffic.
The Town Knobs
Fault
The>The Town Knobs
Fault is part of the Southern Appalachian Foreland
Fold-Thrust Belt in Northeastern Tennessee. The
The Town Knobs Fault places the
Lower Cambrian age Rome Formation in the hanging (upper) wall on
top of Middle Cambrian Maryville Limestone in the footwall (lower).
Both are part of the Conasauga Group. The Conasauga Group includes
the Maryville Limestone plus the Rome Formation as well as the
Maynardville Limestone, Nolichucky Shale, Honaker Dolomite,
Rogersville Shale, Rutledge Limestone, Pumpkin Valley Shale and the
Shady Dolomite
The Rome Formation is a variegated (red, green, yellow)
shale and siltstone with beds of gray, fine-grained sandstone.
Maximum exposed thickness of the formation is approximately 1,500
feet. The primary rock founding the formation is shale with
siltstone and sandstone being secondary. As mentioned earlier, the
formation is lower Cambrian in age.
Maryville Limestone is gray, ribboned with (silt and
dolomite), fine-grained, evenly bedded limestone. Layering is
common with clay shale and light-gray dolomite found locally. The
thickness is approximately from 300 to 800 feet. Obviously, the
primary rock is limestone with conglomerate and dolomite being
secondary rocks. It is middle Cambrian in age.
Normal faults responsible for duplicating and then
offsetting beds in the Rome Formation are found in the hanging wall
of the The Town Knobs Fault. The
yellow-tan beds are actually the same bed repeated by continued
faulting.
Normal Faults within the Town Knobs
Fault
The Maryville Limestone was deposited on a carbonate ramp
that progresses (west) along the axis of the Rome Trough. Maryville
carbonates are thin and grade laterally into deeper water shales
deposited in an intra-shelf basin in the western Rome Trough. Units
within the Conasauga Group are not recognized in this area, and
this interval is called the Conasauga Shale. This intra-shelf basin
extended to the south into in eastern Tennessee
.
The Rome Formation is the bottom of the exposed section at
Thorn Hill. The Rome Formation is early Cambrian in age. The Copper
Creek thrust fault cuts through the Rome Formation. The rocks have
a reddish color, and also, in some places, it shows mud cracks.
This series of rocks could have been deposited in a continental
shelf environment. Earlier, we mentioned the Conasauga Group, both
the Maryville Limestone and the Rogerville Shale are in the
Conasauga Group
The The Town Knobs Fault
is not only dramatic, it is beautiful with the contrasting colors.
Very little vegetation obscures the clean lines of the Fault.
Thousands of people drive by here on an annual basis without a
glance into this bit of geological history. Sometimes modern
progress ruins our topography but in this case it reveals what we
would otherwise not have seen.
Please note: in order for you to claim a find of the
The Town Knobs Fault you must
answer the following questions: 1. Using a protractor
if necessary, give the angle of the fault to within 10 degrees,
2. Estimate to within 50 feet, the length of the fault and
3. Give the elevation at the base (road level) of the fault.
Also, please post a photo of you or just your GPSr with the
fault in the background. All answers should not be posted but
emailed to us. We hope you have enjoyed this little bit of geology
as much as we did. We are certainly not geologists………..far from it!
We have found the subject becoming more and more interesting so
from a strictly amateur point of view, we simply want to share
these wonderful local geological phenomena with you. We are
learning as we go along. Enjoy!
This Earthcache was approved by the
Geological Society of America
| We have earned GSA's highest
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(Decrypt)
Vg vfa'g lbhe snhyg rvgure!
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