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Great Falls Earthcache EarthCache

Hidden : 11/17/2006
3 out of 5
3 out of 5

Size: Size:   not chosen (not chosen)

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Geocache Description:

An Involved Earthcache located at Great Falls Park to get you to learn the Geology, trails and history of this wonderful park!

This Waymark Falls within Great Falls National Park (Virginia), Entrance to the park is 5 dollars per car including a 3 day pass.

Geology of Great Falls:
The geologic history of the falls is an interesting one. After the last ice age, the ocean levels dropped forcing the Potomac river to carve deeper in its path to the sea. The overlying rock was eroded away exposing a much harder, resistant rock formation called the Piedmont. This hard layer is principally made up of highly metamorphic and igneous rock, and may be seen throughout the park. For thousands of years the Potomac river has eroded the bedrock, causing the falls to recede upstream from a point 9 miles downstream near Chain Bridge to its current position at Great Falls. Joint fault plains, natural fissures in the rock substrata where shifting has occurred, exist in many places in the Piedmont Formation between Chain Bridge and the Great Falls. These areas of faulting have loosened the rock, forming areas of weakness. The force of the river has eroded along these areas changing the river's course to its current position. As one walks along the cliff tops, evidence of the ancient river beds can be seen in well-rounded boulders, smoothed surfaces and grooves, and beautifully formed potholes which were once formed on the ancient riverbed. The metamorphic rocks provide jagged rocky surfaces and high-walled cliffs, stark and pristine against the crashing waters of the Potomac at the falls and along Mather Gorge.

To Claim this cache you will have to go to the points below and complete each task.

Visitor Center: N 38° 59.812 W 077° 15.285
1. How many years ago did humans start using the Falls?
2. Who ventured here in 1608?
3. The Earliest use of _________ in the US occured here.
Visitor Center Display:
1. What 5 rocks are on display here?

Life Under the Surface: N 38° 59.794 W 077° 15.217
1. What 3 things impacted this region?

Globally Rare Enviroment: N 38° 59.714 W 077° 15.179
1. What does the yellow indicate?
2. Take a photo of you and your group with GPS here with the falls behind you.

River of Change: N 38° 59.714 W 077° 15.179
1. Where does it start?
2. How far does it drop?

Why is there a Hole in That Rock?: N 38° 59.579 W 077° 14.964
1. How long did scientist estimate?
2. Find another pothole along the trail and take a photo of it and your GPS.

Life on the Edge: N 38° 59.441 W 077° 14.908
1. Photo 3: What provides a stabe home?
2. what thrives in the rocky soils?

If you are Handicapped, i.e. wheelchair or crutches then you only need to answer the questions in blue. This is so everyone can enjoy a part of this park.

Geology Map of the Great Falls region

Additional Hints (No hints available.)