Composed of eroded loess over glacial gravel they are slide prone.
This elevation is named for the Chickasaw Indians who by their
possession of the elevation impeded French river traffic in the
18th Century. At the border between Kentucky and Tennessee, the
left bank of the Mississippi River strikes the western edge of
these uplands, exposing four banks of up to thirty feet in height.
The Chickasaw Bluffs secured Memphis from river floods, while a
rare shelf of sandstone below provided a secure boat landing,
making this the "only site for a commercial mart" between the Ohio
River and Vicksburg, Mississippi.
The above coordinates will take you to a part of the Chickasaw
Bluffs known as Fishgap Hill which is close to Reelfoot Lake.
Because of the bluffs close proximity to the Quake Lake (Reelfoot
Lake) it is believed to be a result of earthquakes of the past.
Some say that there is an earthquake fault below the bluffs but it
is well known that the bluffs were here before the earthquakes of
1811-1812 that formed the lake.
The above picture is of a land slide at Chickasaw Bluff after
the Quake of 1812.
From Fishgap Hill you will be able to see the Upper Blue Basin
of Reelfoot Lake. Reelfoot Lake is the winter home of many Bald
Eagles and vast numbers of waterfowl. While looking at the lake you
will notice larger blocky things in the lake, these are some of the
many duck blinds on the lake used to hunt the waterfowl. One of the
blinds is mine but it is harder to see because it is along the far
bank of the lake. Of course this lake is FULL of fish as well and
until 2005 it was the only lake in the world where it was legal to
commercially fish for crappie. You can see for a great distance
past the lake as well because of the area being ancient flood plain
of the Mississippi River which has changed course in this area many
times over years as it slowly eroded its banks.
The bluff's elevation is partially due to loess deposits. Loess
is defined as wind-blown particles of predominantly silt size.
During and following a sequence of ice age glacial cycles, massive
quantities of water flowed through the area now occupied by the
Mississippi River It is believed that each winter when the vast
flood plains dried, strong winds blowing across the mud flats
picked up large quantities of silt which then were deposited across
the landscape. This process took place over thousands of years.
Here near the source, the silt deposits are deeper but the depth of
loess decreases as one goes eastward from the floodplain source.
Some loess bluffs erode away slowly as they are rained on and the
water runs down the slope. The growth of vegetation such as trees
and ivy can help slow the erosion of the bluff. Loess can also
collapse when water-saturated or if they are under cut by a river.
When loess collapses you will be able to see the many layers of
sediment and gravel in the vertical slope of the bluff.
Three forces came together to create this bluff and others like
it: (1) the grinding action of glaciers pulverized some of the soil
and rock into flour-like silt particles, (2) melt water from the
glacial ice created movement of the silt onto the flood plains and
(3) wind carried the loess to the bluff area and beyond.
To log this earth cache as a find you will need to take a picture
of you with your GPSr and the view from the bluff behind you and
answers the following questions show the educational value of this
earthcache. 1. As to the current appearance of this area of the
Chickasaw Bluffs… Does it appear to have been formed by erosion
(steep but not vertical) or collapse (vertical) of the bluff. 2. As
to the formation of this area of the Chickasaw Bluffs by the
Mississippi River or its Flood waters… Would you say that the
Mississippi River or its flood waters affected this area recently
(in the past 100 years) or long ago (well over 100 years
ago)?