Glacers left WHAT HERE? Earthcache EarthCache
Glacers left WHAT HERE? Earthcache
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As an Earthcache, there is no container to 'find'--instead you will discover something interesting about this area. Please e-mail to my profile the answers to the questions.
REQUIREMENTS:
1- Is it likely that this 'sample' of loess was deposited here by the winds or that it is eroded loess that once choked this stream and altered its course?
2- What is the height and length of this loess 'sample' that this stream has exposed?
3- What is the depth of the clay/sand that is deposited on top of the loess?
4- A pic of you/group would be nice if possibe. DO NOT allow view of the earthcache
FTF: jackthebear
This earthcache is located in the Chicasaw State Park on the side of a commonly used trail. It can be easily observed as the stream has cut away the bank and exposed this 'loess' deposit. Please obey ALL rules & regulations in this beautiful park.
In Tennessee, there was no actual glacial activity, but the glacial ice sheets did advance as far south as as the present day Ohio River, along the northern Kentucky border. So how did glaciers leave 'something' here, when they were not even actually here? Well...
As the glaciers moved south through Ohio, Indiana, and Illinois, the thick ice sheets carved the surface, grinding the underlaying rock into dust-like 'glacial flour.' As the temperature warmed, the glaciers retreated and vast amounts of meltwater and sediment flooded the landscape.
The sediment was deposited, creating huge mud flats. When the meltwaters receded, these mud flats were exposed. As they dried, the fine-grained silt was picked up by the strong prevailing winds. Huge dust clouds were moved and re-deposited over a broad area.
The winds that blew south re-deposited this fine-grained 'rock flour' throughout West Tennessee. This fine grained silty dust was also deposited in the area of this earthcache and can be seen as white-gray layers between the red clay layers in the local road-cuts. These deposits are called-'loess.'
Much of the soil in this area is composed of loess. This ancient wind-deposited silt that erodes very slowly when exposed on nearly vertical slopes, but erodes quickly on flatter slopes. As the ground is broken up in order to plant crops, rain rapidly erodes it, carrying the silt to to nearby ditches, gullies and small streams, choking them and altering their course
Reference: A Geologic Trip Across Tennessee, Harry L. Moore.
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