Cany Fork River's SandStone Protrusion EC EarthCache
Cany Fork River's SandStone Protrusion EC
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As an EarthCache, there is NO container to discover. Rather, with this cache, you discover something about the geology of the area. To receive credit for this 'find' please e-mail to my profile the answers to the following questions. IT SURE MAKES IT EASIER IF YOU SEND THE ANSWERS SOON AFTER YOU LOG SO THAT I CAN ID THEM WITH YOUR FIND! If your answes are not forth coming I will need to delete your find.
REQUIREMENTS:
It is POSSIBLE to make this a slow drive-by, if you have done your home work ahead, by reading ALL of the material beforehand.
1- At this location you can see that you are nearly an hundred feet in elevation above the present riverbed. Compare the elevatin at the exit with your present elevation at the sandstone protrusion. What is the difference?
2- As you observe this sandstone protrusion, about how many layers of the sandstone sediment do you see?
3- What is the approximate height & width of this sandstone protrusion?
4- Determine wheather the 'weathering 'that you are seeing is PRIMARLY mechanical or chemical weathering.
5- List the TYPES of mechanical and chemical weathering that you observe.
U can do this earthcache parked on highway easement!!!!!!!!!
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Long ago this river, which you see in the valley below, was a mighty raging river. Over a long period of time as the river began to receed in size it deposited tons of sand and silt which formed layers and layers of soft sandstone. The sediment also included calcium carbonate or shells from sea creatures which also created layers of limestone. The lime in the limestone mixing with the sandstone helped to bind it.
As the water receeded in this mighty stream most of the sandsone/limestone was eroded away - but this sandstone protrusion was left behind and remains to this day. It is not now eroding but it is deteroriating by a process called 'weathering'.
At this earthcache, you are standing beside a sandstone protrusion, trying to determine the reasons for the 'weathering' that is taking place on this formation.
Weathering is the decomposition of the earth's rocks, soils, and minerals through direct contact with the atmosphere. Weathering occurs without movement, meaning that erosion is NOT considered to be weathering, though erosion may have caused the environment for weathering.
There are TWO TYPES of weathering - MECHANICAL (PHYSICAL) and CHEMICAL.
MECHANICAL weathering - involves the breakdown of rocks and soils through direct contact with atmospheric conditions such as water, ice and preasure. Mechanical weathering is a major cause of the disintergration of rocks. The rock size is brokendown into smaller particles but the rock components are not altered.
CHEMICAL weathering - involves the direct effect of atmospheric chemicals or biologically produced chemicals in the breakdown of rocks, soils and minerals. The composition of the rock components does change in chemical weathering.
The minerals left over after the rocks breakdown combined with organic material ceates soil. The mineral content of soil is determined by its parent soil sources. Thus, a soil derived from a single rock type can often be deficient in one or more minerals for good fertility, while a soil weathered from a mix of rock types often makes a more fertile soil.
TYPES OF MECHANICAL WEATHERING:
THERMAL EXPANSION - This type of mechanical weathering happens when there is a great CHANGE in temperature on a cyclic basis. The stress of the temperature change causes the the peeling off of the layers of rock into sheets. Thermal expansion is increased by moisture.
FROST DISINTERGRATION - This happens in environments with alot of moisture and where the temperature ofter fluctuates above and below freezing. When the water freezes it crystalizes and expands, producing stress on the rock. Sandstone is especially vulnerable to this type of weathering.
BIOLOGICAL WEATHERING - Living organisms may contribute to mechanical as well as chemical weathering. The attachment of organisms to the rock surface enhances physical as well as chemical breakdown of the surface microlayers. On a larger scale seedlings sprouting in a crevice and plant roots exert physical preasure as well as providing for water and chemical inflitration.
TYPES OF CHEMICAL WEATHERING:
DISSILUTION - Rainfall is acidic because atmospheric carbon dioxide dissolves in the rainwater producing weak carbonic acid.It is the case of acid rain, and the acidicness is 2-3X the normal.
CARBONATION - This takes place when rain combines with carbon dioxide. It has an affect especially on sandstone/limestone because the weak carbonic acid formed reacts with calcium carbonate.
BIOLOGICAL-CHEMICAL WEATHERING - A number of plants and animals may create biological/chemical weathering. The decaying remains of plants and the waste of animals form organic acids which, when disolved in water causes chemical weathering.
Great USA weather temp/map: (visit link)
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