do not attempt this cache if you are afraid of heights! You will be on a rope bridge over a river!
It is hard to imagine that this area once was subjected to glaciers! Over 10,000 years ago, when the continental glaciers covered most of northern North America, Europe and Asia, the very tops of these mountains were covered with small glaciers and extended into the valleys. These glaciers carried with them vast amounts of debris randing from sand to boulders.
Cracks in the rock froze during the cold weather, and the ice expanded, widening the cracks. As the glaciers started to melt, debris started flowing down river and lodged themselves in the cracks. As water flowed, it rotated, turned and tumbled the debris in the rocks, rounding the debris and the crack.
As the debris got smaller and smaller from erosion, it washed away and a larger debris fell into the spot and the process began again. Over a period of thousands of years, the rounding continued and each spot grew into the round 'kettles' you see in the rocks below you.
Once the glaciers melted, majority of the runoff gone, the kettles ceased their rapid growth. Today, the kettles grow much slower, but they continue to grow.
access this cache by walking out to the middle of the suspension bridge. If you have a fear of heights, do not attempt this earthcache!
To get credit for visiting this Earthcache, email the answers to the following questions.
1. The subject line and the first line of the email should be "River Kettles: GC3FGMA"
2. While standing on the bridge, locate the kettles in the river below you. Use your compass to note what direction the river is flowing. What side of the rock do the kettles form?
3. Are the kettles roughly the same size or are they various? Why do you suppose this is the case?
4. If the current rate of erosion is about 1/100 of an inch per year, how long did it take to create the 'average' kettle you see below you? Remember, these are 'circles' and erode evenly on both sides at the same time... get your diameter, divide by two and then use your math.... Give it your best guess.
5. I know it is optional, but it would be nice if you posted a picture of your group at the park. I like to see who visited. Hope you have fun.
| I have earned GSA's highest level: |
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