Teton Glacier EarthCache
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An EarthCache provides an earth science lesson through a visit to a unique geological feature. There is no physical container to find but before you can claim a "found it" you must perform the logging tasks associated with the earth cache. Simply posting a photo does not suffice. Found it logs without the accompanying answers having been sent to the Cache Owner will be deleted.
Although most of the earth's glacial ice is contained in polar ice sheets, glaciers can also be found in the mountain ranges of every continent and that is the topic of this earth cache.
Teton Glacier, the largest glacier of twelve named glaciers located in Grand Teton National park, can be found below the north face of the mountain known as Grand Teton, the highest peak in the Teton Range (13,770 ft) and a central part of a cluster of peaks called the "Cathedral Group," comprised of Grand Teton, Mt. Owen (12,928 ft) and Teewinot Mountain (12,325 ft).
More than any other erosional force, giant glaciers from the Ice Age are responsible for sculpting the magnificent Teton skyline. The huge masses of ice in a glacier are quite heavy and glaciers are in a constant state of movement but at a rate that is too slow to detect by the human eye. They have the ability to move rocks and other debris, often quite some distance, and it is this debris movement that, over thousands of years, has formed the spectacular skyline that you see in front of you at the posted coordinates. Teton Glacier is approximately 3700 feet long and 1100 feet wide. It will take a snowflake that lands on the west end more than 100 years to move to the east end where it will finally melt. Snowfall and temperature affect the distance a glacier moves each year.
To demonstrate the educational value of this earthcache, go to the posted coordinates and read the informational sign you will find there. Make some observations while viewing the glacier. Additional information you may need can be found on this cache page. Please do not include the informational sign in if you post optional photos (no spoilers).
Email your answers for the following questions to the CO:
** Please include number and geocaching names of people in your group if emailing answers on behalf of the group.
1. Observe Teton Glacier from the posted coordinates and read the information on the sign - how much surface area has been lost in the past 45+ years? Considering the size of the glacier, does this seem like a little or a lot? What factors can affect the loss of surface area of a glacier?
2. Observe the glacier itself, then look at the photo of the glacier on the informational sign and then look at the photo posted here on this cache page. Compare the three. Based on your observations of the glacier and the photos, do you think Teton Glacier is advancing or receding and why do you think so?
3. Observe the glacier and the surrounding topography. Based on your observations, tell me which type of glacier you think Teton Glacier is and why.
Glacier Information
What are Glaciers?
Glaciers must meet three main criteria in order to be characterized as glaciers:
1. They must be made of ice. (They also contain air, water and rock debris but they MUST contain ice crystals)
2. They must initially form on land (they cannot start out forming over water) and may eventually extend out into water.
3. They must move! (If a patch of snow or ice does not move it is not a glacier.)
Types of Glaciers: There are two main types of glaciers:
1. Unconstrained which include ice sheets, ice caps, ice domes and ice streams. These cover vast areas and are not bound by the local topography.
2. Constrained which include ice fields, outlet glaciers, valley glaciers and cirque glaciers. These glaciers are typically bound within a depression or valley and are found in areas of rugged topography.
Advancing or Receding?
1. Glaciers are created when snow that falls in the area and is then subject to extreme pressure from overlying layers of snow. The snowflakes become compacted and recrystallize into slabs of glacial ice. As the glacier mass increases, gravity exerts its influence and the glacier ice begins to flow downslope. Some of the ice evaporates into the atmosphere but once a glacier reaches it furthest point of movement it wastes (or ablates) through melting. If a glacier receives more snowfall than it loses through the ablation (melting or evaporation) it is said to be an advancing glacier. If the glacier is considered to be receding glacier then it is losing more volume than it is gaining. It may still be moving downslope but it can't supersede its uphill rate of recession from melting.
Freshwater is an important element on our planet. One third of the world's population relies on the fresh water that melts from glacial ice. Many glaciers store water during one season then release it later as meltwater. This meltwater is a critical water source for humans, animals and plants, especially when other water sources may be scarce.
Climate changes such as temperature, cloud cover and precipitation all affect glacial mass. Changes in glacial mass are an important indicator of global climate change and they also affect the variation in sea level.
PLEASE NOTE WINTER ACCESS INFO: The coordinates will take you to a turnout along Teton Park Road. Teton Park Road is closed from Nov 1 – May 1. When the road is closed you may park at Taggart Lake Parking. Coords: N 43° 41.559 W 110° 43.957. It is about 1.5 miles to the Teton Glacier GZ from there and you may hike or bike if there is no snow on the ground OR you may snowshoe or ski in to the area if there is snow. No snowmobiles are allowed on this section of road.
Resources for information on this earthcache page:
http://www2.nature.nps.gov/views/KCs/Glaciers/HTML/ET_Intro.htm
http://en.wikipedia.org/wiki/Teton_Glacier
http://en.wikipedia.org/wiki/Glacier_morphology
http://www.cliffsnotes.com/study_guide/topicArticleId-9605,articleId-9519.html 
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