This is not a typical Geocache, it is an EarthCache. You will not find a "cache container" at the posted coordinates. Instead, an EarthCache is designed to bring you to a geological feature to learn something about our great Earth. See http://www.earthcache.org/ for further details.
Park at the designated waypoint and follow the bridle trail around the right side of the pond to the posted coordinates.
The ridge of hills on which you are standing extends from Plainfield through Scotch Plains to Metuchen.
These hills are irregular in outline and are relatively short in height, hence they are known as the "Short Hills." The Short Hills were formed during the late Pleistocene Epoch (familiarly known as the Ice Age) when the most recent glacial ice sheet to reach New Jersey, the late Wisconsinan, retreated about 17,000 years ago. At its farthest advance, this glacier deposited soil and rock in the form of a "terminal moraine." With their gentle ridge, knoll, and swale topography, the Short Hills are part of this moraine at the terminus of the glacier.
Map showing the Glacial Ice Sheet and the Terminal Moraine in New Jersey and New York
A "moraine" is a glacially formed accumulation of glacial debris (also called "till"). Similar to material being moved by a bulldozer, the soil and rock at the leading edge of the glacier was pushed no farther and was dumped in a heap at the terminal end of the glacier. This glacial debris may have been plucked from a valley floor as the glacier advanced or it may have fallen from the valley walls.
This till includes sand and gravel, with some pebbles and cobbles, and a few boulders. Some of the till includes "glacial erratics" that differ from the rock that is native to this area because they were carried by the glacial ice from a different geological formation. Glacial erratics can be traced back to their parent bedrock to determine the flow of the glacial ice sheet. The composition of the till in the Short Hills reflects glacial erosion of red shale, mudstone and sediments in the nearby area, as well as metamorphic and sedimentary bedrock from the north.
Diagram of geologic formations created by a retreating glacier
Notably, the Short Hills are marked by many depressions or pits. These depressions are called "kettles" or "kettle holes" because of their similarity in shape to the kitchen utensil of the same name.
The kettles were created when large blocks of ice broke off from the receding glacier and became trapped in the sediments of the terminal moraine. When these terrestrial icebergs melted, depressions were formed when the sediments deposited by the glacier collapsed into the void left behind by the melted ice.
In most cases, kettle holes eventually fill with water, sediment or vegetation. A large kettle is called "kettle lake." If the kettle hole receives its water from precipitation, the groundwater table, or a combination of the two, it is termed a "kettle pond" and it is called a "kettle wetland" if it is vegetated.
Because these kettles are filled with water during much of the year, they provide a valuable habitat for amphibians, birds and other wildlife.
To log this EarthCache, go to the posted coordinates and answer the following questions.
1. At the posted coordinates, approximately how many ponds do you see? What is the shape of the ponds? Are the ponds all the same size or are they various sizes? Why do you think this is the case?
2. Where you are standing was literally "ground zero" at the edge of the glacier's advancement. Imagine the face of the glacier towering above you, with large blocks of ice breaking off it! Estimate the volume (in gallons or in liters) of the ice block that would have created the nearest kettle hole to the north of the posted coordinates.
3. In which direction are the ponds oriented relative to each other? (If you don't have a traditional compass or an electronic compass on your GPSr, provide your best estimate. Magnetic declination in this area is approximately 13 degrees.) How do you think that the surrounding hills were formed? In which direction do the hills slope? Based on the direction of the ponds and the slope of the hills, in which direction do you think that the glacial ice sheet would have been?
4. There is a large granite boulder at the posted coordinates. How do you think that it got there? Rocks and gravel of the glacial till are exposed in a ravine right next to the boulder. Are the rocks all the same size and shape? Are the rocks all the same type? Why do you suppose that this is the case?
5. In your log, post a photo of yourself and your GPSr with one of the ponds in the background. (Optional)
