This earthcache is located in the Saratoga Woods Preserve. The hike to the cache is approximately 1 mile round trip with no real significant elevation gain. Besides offering the opportunity to see glacial traces, this area affords many miles of hiking through quiet forest paths. Parking coordinates are provided. Nearby, a kiosk shows the trail system. Begin by taking the uphill trail to the right. This will lead you to the intersection of Wood Nymph and Bent Tree Trails. Veer to the left on Bent Tree Trail which will eventually cross an old landing strip. The short trail to the cache site is on the left side of the strip at the provided coordinates. The earthcache is located just 250 feet from there.
A glacier is basically an accumulation of snow that lasts for more than a year. In the first year, this pile of snow is called a névé. Once the snow stays around for more than one winter, it's called a firn.
As more and more snow piles up over the years, the weight of the snow on top starts to compress the snow on the bottom. This compression turns the snow to ice. The compression of the glacier continues for years, adding more and more layers on top and adding even more weight. The ice eventually gets compressed so much that most of the air is forced out of it. This is what causes glacial ice to appear blue.
Eventually, the glacier becomes so heavy that it starts to move. When a glacier moves, it isn't like a solid block of ice tumbling down a hill. A glacier is a river of ice. It flows. That's because the highly compressed layers of ice are very flexible and under great pressure.
Glaciers have two main sections: the accumulation area and the ablation area. The accumulation area is where temperatures are cold and snow collects, adding mass to the glacier. The ablation area is where temperatures are warmer, so some of the glacier melts. The average balance between areas determines the stability of the glacier. A glacier with a much larger average accumulation area is growing, while one with a larger ablation area is a glacier that's shrinking and could eventually disappear, like the one that moved through this earthcache site.
Glaciers don't pass through the land quietly. As a glacier moves, it picks up rocks, some of them very large. The repeated melt/freeze cycles that occur inside and beneath a glacier pry them from the ground. The rocks on the bottom are ground together as they're carried along. The glacier's weight breaks down the rocks buried deep inside the ice. Not all rocks are ground down. Some are too big, or stay at the perimeter of the glacier. When a glacier recedes (by melting), it leaves the rocks it was carrying behind called erratics. Today, numerous erratics can be seen on Whidbey Island. Another geological sign that a glacier has stopped by are striations. Glacial striations or glacial grooves are scratches or gouges cut into bedrock by process of glacial abrasion. Glacial striations usually occur as multiple straight, parallel grooves representing the movement of the sediment-loaded base of the glacier. Signs of movement could be channels, grooves or striations depending on the size of the sediment contained in the glacier. Large amounts of coarse gravel and boulders carried along underneath the glacier provide the abrasive power to cut the grooves, and finer sediments also in the base of the moving glacier further scour and polish the bedrock. Geologists use these markings to determine the direction the ice took when the glacier receded and the size of the sediment that caused the striations.
As proof of your visit:
Take a picture of yourself in front of the erratic.
Answer the following questions:
1) Based on the striations that you have found what direction do you think the glacier was moving when it came through this area?
2) What size sediment caused these striations?
3) Do you see any other evidence nearby that would support glacial activity in this area?
Please e-mail the answers to us but do not include them with your found log! Failure to do that in a timely manner will result in a log deletion.You do not need a response from us in order to log this cache. We hope you have learned a thing or two about glaciers and thanks for visiting Saratoga Woods.
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Warning: Earthcaches come with a unique set of rules and activities that must be met
before successfully logging. Failure to comply will result in a log deletion.
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