Please send answers to the following questions the CO within two days of your visit.
Go to the GZ coordinates for this EarthCache. There you will find a large quartzose rock similar to those found on Parson's Mountain, 14 miles to the northeast. Look at the rock itself and the area within a 20 yard radius and answer this question:
1. What natural force or forces have caused this outcrop of bedrock to protrude above the surrounding surface: a) uplifting; b) weathering; c) erosion; d) folding and faulting; e) both a and c.
Elberton, GA, just across the river, claims the title of "Granite Capitol of the World." The park at this EarthCache contains two large examples of Elberton granite.
2. Identify the two places in the park where granite is used and then explain why you feel granite (rather than some other stone) was used here.
Leave the park where the rock and the granite slabs are located, turn right out of the entrance and continue down toward the water. Park your car in the area provided and walk down to the boat launching area but continue on the cement walkway north toward the dam. Go out onto the concrete pier and look at both shores, Georgia and South Carolina.
3. Describe what precautions have been taken to prevent erosion of the river banks, and why these precautions have to be taken at this particular site.
4. Please feel free to upload pictures of yourself and your group in front of any of the points of interest. Hope you enjoy this little pocket park and the views up and down river. Thanks for taking the time and making the effort to visit this earthcache!
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Granite facts from the Elberton Granite Association
Source: http://www.egaonline.com/
Granite is a tough, durable rock composed primarily of three different minerals. These minerals are easy to see due to their different colors. The white mineral grains found in granite are feldspar. It is the most abundant mineral found in granite. The light gray, glass-like grains are quartz, and the black, flake-like grains are biotite or black mica.
The Elberton Granite deposit is a mass of granite approximately 35 miles long, six miles wide and most likely two to three miles deep. The total amount of granite in the Elberton area is approximately six million million tons. That is enough granite to fill the Rose Bowl nearly two million times.
Elberton granite began 325 million years ago as a large, hot (1300 degrees to 1400 degrees Farenheit) mass of magma or molten rock. This magma originated when some of the earth's crust melted -- probably at a depth of about 11-12 miles. The magma rose upward and came to rest about nine miles beneath Elberton. There it cooled very slowly -- taking more than a million years -- and solidified into granite. That was more than 300 million years ago. Since then, the granite has been pushed upward, and the land above it has been removed by erosion. The result is a granite deposit that lies just beneath the earth's surface where it can be easily, safely and economically quarried.
The hardest material on earth, diamond, has a hardness of "10". It can only be scratched by other diamonds. The softest materials have a hardness of "1" and are easily scratched. Few materials, except precious, stones are harder than "7". Elberton granite is very hard, "6"-"7", and is very tough to break due to its tightly bonded quartz and feldspare grains as well as their atomic structure. No other natural stone used for commercial purposes is any harder or more difficult to break than granite.
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Richard B Russell Dam
Source: http://www.sas.usace.army.mil/About/DivisionsandOffices/OperationsDivision/RichardBRussellDamandLake/Hydropower.aspx/
Richard B. Russell Dam and Lake was the U.S. Army Corps of Engineers third multipurpose “project” in the Savannah River Basin. Authorized by Congress under the 1966 Flood Control Act, the Russell Project was built between 1974 – 1983 for the purposes of hydropower, incidental flood control, additional stream flow regulation, water supply, water quality, recreation, and fish and wildlife management. Filling of the lake began in October 1983 and was completed in December 1984. The powerplant first went on-line in January 1985. The powerplant originally consisted of four conventional generators. The addition of four pumpback units was completed in 1992
Russell Dam is a concrete-gravity structure flanked on both sides by embankments of compacted earth. The concrete section is 1,884 feet long and is 210 feet at its highest point. The earthen embankments on each side of the dam are 2,640 feet. The dam creates a 26,650-acre lake on the upper Savannah River, 30 miles downstream from Hartwell Dam and 37 miles upstream from J. Strom Thurmond Dam. Hartwell Dam located near Athens (completed in 1962) and J. Strom Thurmond located near Augusta (completed in 1954) join Russell to form a chain of lakes 120 miles long.
Downstream Safety
The production of hydropower at the powerplant is accompanied by a rise in the level of the river below the dam, as water used to drive the generators is discharged into the river. Air horns located on the top of the dam will sound for one minute before water is released into the river. The horns are to alert fishermen and other visitors who might be on the rocks in the riverbed that the river will soon rise and that they must immediately move to the riverbank. For safety’s sake, fishermen are encouraged to fish from the riverbank or from the fishing piers that have been provided.
Flood Control
Normally, water released from the reservoir passes through the dam and into the river below by way of the powerplant. However, there are times when it is necessary to pass substantial quantities of water downstream quickly for flood control purposes. The spillway, located on top of the dam, contains 10 large gates, each 50 ft. by 45 ft., for the quick release of water from the lake. Water can be released at the rate of 5.8 million gallons per minute with all floodgates open one foot. The training walls of the concrete structure at each end of the spillway direct the flow into the river channel below the dam.
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Glossary of Terms:
Erosion:
Breakdown and removal of rock material by flowing water, wind, or moving ice. Not to be confused with weathering! . (Source C) Erosion is the process by which soil and rock particles are worn away and moved elsewhere by gravity, or by a moving transport agent – wind, water or ice. Transport refers to the processes by which the sediment is moved along – for example, pebbles rolled along a river-bed or sea shore, sand grains whipped up by the wind, salts carried in solution. (Source B) How is erosion different to weathering? Erosion involves removal of solid material by a transporting agent. Weathering is the breakdown of rock into fragments at the Earth’s surface. No movement is involved in weathering. (Source B)
Faults:
Deep cracks caused by movement of rock during earthquakes. Different rock types are often seen on each side of a fault. . (Source C) Normal faults occur when tensional forces act in opposite directions and cause one slab of the rock to be displaced up and the other slab down (Source D)
Folds:
Bending of rock layers caused by compression of rocks, usually as part of mountain-building when tectonic plates collide. (Source C) A fold can be defined as a bend in rock that is the response to compressional forces. Folds are most visible in rocks that contain layering. (Source D)
Uplift:
When a region is literally lifted up as the crust is squeezed by tectonic forces or, sometimes, following the melting of ice-sheets. (Source C) Understanding the idea of Uplift is the key to making sense of the rock cycle, as it allows us to see rocks that were once deeply buried beneath the surface. If rocks did not get uplifted to form hills and mountains, then the processes of weathering and erosion would long ago have reduced much of the world’s land-masses to low-lying, flat plains. Weathering and erosion, transport and deposition would all effectively stop. Scientists believe that, if all these active processes of the rock cycle ceased to operate, then our planet would cease to be able to support any life." (Source A )
Weathering:
Slow breakdown of rock at the Earth's surface, due to climatic and biological processes. (Source C) How is erosion different to weathering? Erosion involves removal of solid material by a transporting agent. Weathering is the breakdown of rock into fragments at the Earth’s surface. No movement is involved in weathering. (Source B)
Source A:
http://www.geolsoc.org.uk/ks3/gsl/education/resources/rockcycle/page3468.html
Source B:
http://www.geolsoc.org.uk/ks3/gsl/education/resources/rockcycle/page3462.html
Source C:
http://www.geolsoc.org.uk/ks3/gsl/education/resources/rockcycle/page3451.html
Source D:
http://www.physicalgeography.net/fundamentals/10l.html
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Thanks and appreciation go
to the Army Corps of Engineers
at the Richard B. Russell Dam and Lake
for giving their permission for this EarthCache.
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