Template:POTD/2010-07-23
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2010 July
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Picture of the day
The "Giant Marbles"
rock formation
in
Joshua Tree National Park
, located in
California
, United States. These spherical boulders were formed
100 million
years ago from the cooling of
magma
beneath the surface.
Groundwater
is responsible for the
erosion
that created the spheres from rectangular blocks.
Photo:
Mila Zinkova
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