The Rock Garden EarthCache
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Large blocks of bedrock formed during the Pennsylvanian period produced the Rock Garden (also known as the Labyrinth).
Other Earthcaches in the region discuss the types of rock in the area at length, and this Earthcache does not intend to duplicate those discussions. This location offers the Earthcacher a fantastic array of massive natural rock formations. Located in the Endless Mountains region of the Allegheny Plateau, the labyrinth is a series of pathways, gaps, and rock structures along the Canyon Vista trail.
You will pass structures similar to these on your way into the Labyrinth.
Some Technical information:
The Pennsylvanian period occurred 320-290 million years ago, part of the Carboniferous age. The park was an ancient river delta along a coastline of clay, mud, and sand on a sea long ago.
The coast suffered significant upheaval as continents moved and a mile of erosion created the resultant solidified rock you see before you.
In addition, the Pleistocene ice age (and the related glacial melt at its end) had extraordinary effects on the rock you see millions of years later.
The Pennsylvanian period's Pottsville Formation has an interesting origin.
Our Focus:
The intent of this Earthcache is to provide insight into how the Rock Garden was formed. Following the upheaval, and associated glacial melts and erosion, the area was affected by frost wedging. Paraphrasing the source, The expansion of ice causes a weakening of the existing rock which is dissected over time. Expansions of ice within the rock followed by reductions weathers the rock. The actual expansion of ice via wedging is around ten percent per cycle. The expand/reduce cycle creates stress on the rockbed.
As you can imagine, continuous freezing/melting actions and the related stress generated the gaps, angles, and blocking of the rocks in the area. The splitting of rocks along the joints into blocks is called block disintegration.
The blocks are bounded by weathered vertical joints that make an intricate series of deep, narrow passageways. The openings range from 1-3 feet in width and are between 10-20 feet deep. At your location the blocks usually intersect at right angles.
The Earthcacher may, if possible, walk on top of the formation and cross nearly the entire garden above ground. If you do, you'll see varying sizes of rock at that level, including views of the gaps in the rockbed; pathways between the blocks of rock; smoothed surfaces; and layers of rock from a side view within the gaps.
As you walk at ground level, you'll find numerous pathways. Attempt to find one of the passageways that contains a "doorway" (straight into the center of the garden as you arrive and a path off to your left). Try to imagine how that "doorway" was formed over time.
As you move around the entire outside semi-circle of the garden, you'll see evidence of smoothing, blocking, layering and the path gaps created by the wedging.
Questions:
(1) What do you believe caused the weathering? Frost wedging, high pressure, volcanic activity, water flow, wind, stress, ice, or erosion?
(2) What do you believe created the "doorway" in the passageway?
”GoingToPot” has earned (GSA) Geological Society of America's highest earthcache level:
Platimum Earthcache Level is awarded by Geo Society .org for visiting and logging twenty or more EarthCaches in five or more states/provinces/countries and have created three or more EarthCaches.
Permission: 
In order to insure permanence of your smiley, take a moment and send your answers to the questions to the cache owners.
References: wikipedia (world's end state park) (frost wedging)
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Treasures
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