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This is an entry level cache. One needs only to walk a short distance on city sidewalks to get to this geologic feature. The potholes sit below a public walkway and southeast of a small wooden dam. A few shops are located near the site.
To get to this site drive Massachusetts’ Route 2 to Route 2A into Shelburne Falls center. Once in the center find parking within the vicinity of the steel bridge that passes over the river that divides the town. Use your GPS from where you parked the car to find the observation point/deck that sits above the potholes. This area is located along a public walkway and has a few benches to relax in while viewing the geological features. After observing the potholes, take some time to enjoy Shelburne Falls. It’s a quaint little town with some nice shops and eateries to eat some lunch or enjoy a breakfast.
How did the potholes located at Shelburne Falls get there? Well glacial melt water washed over the metamorphic rock that can be observed at the falls. The rock itself is called gneiss, which is a very hard and resistant to erosion type of rock. At the time of the last ice age, about 15,000 years ago, there were approximately 2,000 feet of ice that covered Shelburne Falls. As the last glacier melted the Connecticut River Valley, where Shelburne Falls now sits, was flooded. This flood created a huge glacial lake. This glacial lake became known as Lake Hitchcock. As the lake drained, it caused the flow of the Deerfield River to swell. The river carried in its rushing waters a large load of stones, sand, and mud. It began to erode the hard, metamorphic, rock called gneiss over which it flowed. As you can imagine the run of from this glacial lake must have been significant. (Shelburne Falls Website, 2007)
As this water washed over Shelburne Falls the water picked stones and sediments of various sizes and they became trapped in cracks that then, literally, drilled into the underlying metamorphic rock. With the vast amount of melt water run off the pressure of flowing water kept the smaller stones tumbling around for thousands of years. Additionally as some stones are eroded away they were replaced by more stones and this allowed the process to continue. If one images a washing machine, except with stones in it, one can easily see how these potholes became so perfectly round and wide. In fact there is one pot hole at the site that is believed to be a world record size pothole. (Skehan, 2001)
Over time the stones that tumble around inside the pothole eventually break through the down stream side of the hole and the forming of that individual whole is completed. (Skehan, 2001)
The main reason that the potholes can be seen presently is because the river is dammed near the observation deck. You can walk down stream and see many more of these fascinating holes of various sizes. There are about 50 potholes in all. The process mentioned above continues to this day. In the spring when the Deerfield River’s water rise, the potholes can be covered by running water and the washing machine with stones in it action continues. (Shelburne Falls Website, 2007)
Check the cache logs for a picture of the potholes as I’ve had difficulty in uploading the picture on to the cache submittal page.
Enjoy your day; Shelburne Falls is a nice place.
In order to get credit for this cache you must do the following:
1. Determine the direction that the stream flowed when the glacier melted. Please give a magnetic azimuth.
2. E-mail your findings along with a picture of your GPS with potholes in the background.
Visiting this cache site accomplishes several Massachusetts’ required teaching standards in Science and Technology.
Massachusetts Frameworks:
• Give examples of how the surface of the earth changes due to slow processes such as erosion and weathering, and rapid processes such as landslides, volcanic eruptions, and earthquakes.
• Describe and give examples of ways in which the earth’s surface is built up and torn down by natural processes, including deposition of sediments, rock formation, erosion, and weathering.
• Explain and give examples of how physical evidence, such as fossils and surface features of glaciation, supports theories that the earth has evolved over geologic time.
• Use technology such as GPS.
Inquiry Skills:
• Observe the world from a scientific perspective.
• Articulate and explain the major concepts being investigated.
• Identify and use navigation features of a browser
• Using a browser, “bookmark” a Web site for future reference
• Using e-mail create and send a message
Resources:
(2007). “Pre-K through Grade 12 Curriculum Frameworks”: Massachusetts’ Department of Education. Retrieved September – December 2007:
Skehan, James. (2001) Roadside Geology of Massachusetts. Missoula, Montana: Mountain Press Publishing Company.
Additional Hints
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