Glacial Striae EarthCache
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This is a tough mountain hike; know your physical limitations. You will hike 4 miles round trip over steep and rocky terrain climbing 1,800ft on the White Dot Trail. Do not attempt in poor weather unless you are an experienced hiker. Leave no trace behind
Attention: abide by park rules for your safety and respect of the mountain and be prepared for inclement weather while on hike. Although Monadnock is a challenging hike it is frequently visited each year by over 100,000f hikers.
Monadnock is said to be the second most frequently climbed mountain in the world, after Japan's Mt. Fuji. It is a hiker friendly park. The park is open year round but unless you have hiking experience in extreme weather hiking in winter is not recommended. Wear broken-in boots, bring plenty of water in plastic containers, have rain gear packed, dress in layers and stay on marked trails. For more information on the park go to (visit link)
Begin your hike from the state park headquarters located at the entrance to the park. The park is located in Jaffery, NH not far from route 124. Hike the white dot trail. The glacial striae are found along the White Dot Trail just below the summit at approximately 2,980ft ASL.
As the last continental glacier passed over the mountain striae was left behind. A glacier is a huge mass of ice that forms in locations that have large snow falls and temperatures that remain consistently cold. New England experienced an ice age about 13,000 to 25,000 years ago and the cold conditions provided the environment necessary to create the glacier. The sheet of ice was approximately 2,000 to 3,000ft thick. It literally covered all of New England. In fact Long Island, New York was formed from this massive glacier.
A glacier is one of the most powerful agents of erosion. Glaciers erode by plucking away at rocks beneath it and by abrasion. As a glacier moves it carries within its ice materials of all sizes. They range from huge boulders to small particles of clay sediment. Materials caught in the glacier are called its load. Some of this material stuck in the bottom of the ice scrapes away soil and carves grooves into rock. The bottom of the glacier acts as a huge file. You have probably dropped an ice cube on the ground before. You probably observed clods of dirt and small pebbles stuck on the ice. Image this same kind of picture, but on a much grander scale.
The bottom of the glacier carved out the striae you will observe. After the glacier melted and retreated at the end of an ice age the striae were exposed.
Striae are of particular interest to geologists because they indicate which direction the glacier traveled as it passed over a particular location. Striae can be observed at this cache and tell the story of the glacier’s movement across Mount Monadnock.
In order to get credit for this cache you must do the following:
1. At the cache site position yourself so that you face away from the mountain. Using a compass, determine the magnetic azimuth (direction) that the striae point. What is that azimuth? To get credit you must be within five degrees plus/minus tolerance. What direction did the glacier move over the mountain?
2. Using a tape measure determine the area carved out by the glacier (length X width) you should be correct within one foot plus or minus.
3. Email me your results and answers.
You do not have to get the next question correct to get credit for this cache, but it will cause you to investigate a little bit.
4. At the site you will see what looks like a tarry black paint splashed on the south side of a large piece of rock that runs in 295 degree magnetic azimuth. This is a mineral. Name that mineral.
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.
Inquiry Skills:
• Observe the world from a scientific perspective.
• Articulate and explain the major concepts being investigated.
• Measure with accuracy and precision.
• Use appropriate metric/standard international (SI) units of measurement for mass (kg); length (m); time (s); force (N); speed (m/s); acceleration (m/s2); and frequency (Hz).
• 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
Hints/Spoiler Information:
The cache site sits above the intersection of the white cross and white dot trails above tree line.
Additional Hints
(No hints available.)