Red Bluff
Red Bluff is an escarpment (cliff face) located on the western edge
of the Pearl River floodplain in Marion County, Mississippi (near
the community of Morgantown, about 10 miles northwest of Columbia).
MS Hwy 587 previously ran along the upper edge of the escarpment.
The highway was slightly shifted twice in the past because of
advancing erosion; recently, the MS Department of Transportation
permanently relocated the roadway about 350-ft to the south west,
removed a section of pavement in the old roadbed, and installed
vehicle barriers. Ample parking is available at either end, and the
access roads (old section of highway) are well signed.
Some claim that “Mississippi’s Little Grand Canyon” is
Mississippi’s most beautiful natural feature. The top of the bluff
has an elevation of about 360-ft above sea level, offering a
commanding view of the Pearl River floodplain and surrounding
terrain (generally below 200-ft elevation). The escarpment has
about 100-ft of reveal from the upper rim to the springs at the
base. The springs feed into a creek that drops at a gentler grade
(about another 100-ft) to where it joins with the Pearl River.
The bluff face is an exposure of the Citronelle Formation, which
is composed of alternating units of sand and sandy gravel,
strikingly colored dark red to yellow to white, very lightly
cemented into soft sandstone. Very little silt or clay is present,
but trace deposits of almost pure clay can occasionally be found.
The sand grains are composed primarily of quartz, with small
amounts of heavy minerals and feldspar. The gravel is composed of
varying percentages of chert, flint, jasper, rip-up clasts, quartz
and tripoli, including a small fraction of Paleozoic fossils. Most
particle sizes vary from medium sand to coarse gravel; the largest
particles present are occasional boulder-size rip-up clasts.
Erosional Escarpment
While relatively new in a geologic time frame, Red Bluff is not new
to humans and was not caused by construction of Hwy 587. It was
caused by natural erosion of the bluff and appears on early
exploration maps of the area. Two major sources of erosion are
continuing to carve and shape the bluff. The most obvious source is
rain that falls on the hill above the escarpment and runs over the
edge as well as rain that falls directly on the eroding area. This
runoff directly causes the erosion that is moving the escarpment
backwards and that caused the closure of old Hwy 587.
A more hidden but still significant source of erosion is in the
form of springs. Water flows below ground through the layers of
sand and gravel, exiting the ground at the base of the bluff. This
steady flow of water is much slower than that of a massive runoff
during and after a summer thunderstorm. But its continuous action
slowly and steadily moves particles of sand away from the
escarpment, clearing the way for more erosion during the next
thunderstorm.
Other Features
A traditional Geocache (GCHANB) is hidden somewhere in the trees in
the middle of the ravine. Seeking that cache involves considerable
off-trail hiking, bushwhacking, and climbing, and is not to be
attempted lightly.
Many additional interesting geological features are present at
the base of the escarpment. Springs, braided streams, small
waterfalls, quicksand, and confluences are in abundance. However,
these features are on private property and cannot be listed as
Earthcaches without permission.
Sources
Off the Beaten Path: Mississippi (A guide to Unique Places)
by Marlo KirkPatrick
Transactions, Gulf Coast Association of Geological
Societies, Vol. 33, 1983
http://www.mcdp.info/tourism/red_bluff.html
Logging Requirements
1. Post a picture of yourself (preferably with GPS Receiver in the
picture) with some part of Red Bluff in the background. The picture
must be taken anywhere along old Hwy 587, as the bluff itself is on
private property.
Answer the following questions while on site:
2. How many major geological layers can you see (major changes in
color)?
3. Using your GPS receiver, determine the length of the erosional
escarpment (north-west to south-east, along the abandoned road;
it's farther than 600-ft, keep walking).
4. Is the bluff composed of sand and gravel, sand and clay, or
gravel and clay?
5. Name two major sources of erosion that continue to form the
bluff.
Legalese: Please do not post answers in your log; email
them to me through the link to my profile at the top of the page.
Please complete all logging requirements within a few days of
posting your "Found It" log or your log will be deleted. If you
can't complete requirements within a few days you can post a "Note"
to preserve your cache find order or else send me message asking
for an extension. Enjoy the view!
This Earthcache was approved by the
GSA
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