Parking is available in a small lot near the Cottonwood
Springs campground. There is a short hike up to the mine that
includes some steps but it is an easy hike. Still, go prepared
with enough water. As a precaution, do not attempt to enter
the gated mine, or any other abandoned mine in the park as
they are dangerous and could be filled with poisonous
gasses.
Throughout the Joshua Tree area there are many abandoned mines.
Many of these mines sought to extract the gold found along quartz
veins that formed in the monzogranite. The formation of these veins
begins with the slowly cooling granitic magma. As the magma cooled
it solidified and began to contract as hot rock takes up more space
than cooler rock. Water and volatile material that was dissolved in
the magma are forced out as the solids form. The water that was
forced out of the magma is rich in dissolved minerals. The
contraction and added pressure of the water eventually caused
fractures, large cracks, to form in the rock.
The mineral-laden ground water filled the fractures. Gold
actually has a relatively low melting point, so it often will
travel with the water. Continued cooling and possibly a release of
pressure as the region was uplifted forced some of the minerals to
precipitate out of the ground water filling the cracks with
crystals and allowing the gold to solidify. The speed at which the
minerals precipitate determines the size of the crystals that grow
in the crack.
Here at Mastodon mine, the crack was filled with quartz and
gold. The quartz vein can still be seen to the south of the
mineshaft. It was followed deep into the mountain until it
encountered a fault that cut off the vein. The vein was never found
again and the mine abandoned.
Logging requirements:
Send me a note with :
- The text "GC1BPYY Mastodon Mine" on the first line
- The number of people in your group.
- How recently was the mine worked?
- What color and width is the remaining quartz vein?
- What direction do the mine shaft and quartz vein go into the
mountain?
The following sources were used to generate this
cache:
- Trent, D.D. & Richard W. Hazlett, Joshua
Tree National Park Geology, Joshua Tree National Park Association,
2002
- US Department of Energy, Ask A Scientist
General Science Archive Gold Formation,
http://www.newton.dep.anl.gov/askasci/gen99/gen99242.htm
Placement approved by the
Joshua Tree National Park