Rock Piles - Geology Tour Post 5 EarthCache
Rock Piles - Geology Tour Post 5
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Difficulty:
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Terrain:
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Size: 
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This earthcache is located along the Geology Tour Road in Joshua
Tree National Park. The road is available by any main park entrance
or via Berdoo Canyon jeep trail from Indio Hills. Much of the road
is dirt or sand, therefore 4 wheel drive is recommended.
These are some fantastic piles of rock. Have you ever
wondered how they got stacked that way?
Well, actually, they grew that way!
Millions of years ago, the monzogranite that you see piled on
either side of the road was magma being pushed toward the surface.
As these molten masses cooled miles below the surface, vertical
cracks or joints began to form. Pressures pushing the rock toward
the surface, and the relief of pressure as the topsoil eroded has
caused the horizontal joints combined with the vertical joints into
criss-crossed joints, or what are called conjugated joints. These
joints allowed water containing carbon dioxide to flow through,
slowly breaking down the rock surface into individual minerals, or
soil. As time progressed, erosion help remove the topsoil, exposing
these rock formations that you see today.
To log this earthcache:
Find an example of conjugated joints that are not yet separated
into individual rocks, and post the coordinates, and photographs if
possible.
This can be from anywhere along the trail, or in the park, not
restricted to this exact location. It's not that difficult.
In addition to this earthcache, there are numerous other geological
features to behold, and you can pick up the 'Geology Tour Road
Guide' pamphlet at either the Cottonwood or Oasis Visitors Centers
for just 25¢.
The following sources were used to generate this cache:
"Geology Tour Road Guide" pamphlet from Joshua Tree National Park
Association
"Joshua Tree National Park Geology" ISBN 0-9679756-1-1
Whenever you leave your vehicle, please be aware of living
"biological soil crusts", and help to preserve.
For more info, visit www.soilcrust.org
Placement approved by the Joshua Tree National Park
Additional Hints
(No hints available.)