Columbus Bluff Earthcache EarthCache
Columbus Bluff Earthcache
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The Columbus bluff is a historic loess bluff overlooking the Mississippi River at Columbus, Kentucky. It is part of a landscape feature that extends along the Mississippi River as far South as Louisiana.
Often geology has played a part in history. This is a story of loess, blended with an historical event. The bluffs of Columbus-Belmont State Park played a role in the Civil War. This park includes the site of a former Confederate fort. The elevation of the bluff gave a commanding view of the Mississippi River looking across toward Missouri. That is why the fort had been placed here. In addition to the fort earthworks, there is an anchor and a piece of the chain that had been strung across the river to block movement of Union gunboats.
Approach Columbus on highway 123. The park entrance on Cheatham Street is well marked. Drive the park road until it ends at the parking lot at N 36 45.897 W 089 06.715.
A substantial part of the bluff's elevation is due to deposition of loess. 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 as deep as 40-50 feet. Many of the soils of the Jackson Purchase consist of this loess. The depth of loess decreases as one goes eastward from the floodplain source. Fifty miles to the East, in Calloway County, Kentucky the loess depth averages six feet, deep enough for the soils to be highly productive. On the steeper slopes the loess may have eroded away, leaving other soil parent material.
Properties of loess are important. Loess, when water-saturated, becomes slippery and cannot bear it's own weight. This instability has led to the collapse of portions of the bluff south of here at Hickman, Kentucky, where the U.S. Army Corps of Engineers have attempted to stabilize that bluff to prevent loss of land and homes.
Gullies in loess tend to be steep sided. Author Bruce Catton, in his book, "This Hallowed Ground" has said that along the Mississippi River Valley some of the Confederate forces took defensive positions along the gullies found in the loess bluffs. In other words, the gullies, like trenches, offered protective cover bothe for men and their weapons. As you walk up the hill toward the lookout house, notice the deep gully (north)to your right
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. Some other major loess bluffs in the U.S. parallel the Missouri River system with especially prominent bluffs in western Iowa and eastern Nebrasks.
When logging your visit, post a picture of yourself at the lookout house with the river in the background. E-mail me the answers to these questions: 1. What is the weight of one link of the chain that was stretched across the river. 2. Estimate the depth of that gully located to your right as you face the river.
Some references: Humphrey, Maurice E., Frank L Anderson, Raymond A. Hayes and John D. Sims. Soin Survey of Calloway and Marshall Counties, Kentucky. United States Department of Agriculture, Soil Conservation Service. December 1973.
Arlington, KY 7.5' USGS Map.
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