Kilbourne's Hole is a unique volcanic feature that is found in
only a few places in the world. It is called a Maar Volcano.
A maar volcano is formed when Magma is rising and encounters
water saturated ground. The ground can not contain the resulting
steam pressure that builds and a large area is blown out in a steam
explosion. Very little volcanic material is emitted, other than
steam.
Another interesting fact about this area is that it is one of
the few places in the world that yields gem quality Peridot. This
mineral was formed during the rise of the hot magma and was ejected
in the form of Olivine bombs. Many rock hounds and geologists
descend upon this area to search out this highly prized
semi-precious gem.
The hole is approximately 1.7 miles long by 1 mile wide and at
least 400 feet deep. There are basalt cliffs as well as well
defined layers of ash ringing parts of the crater.
Apollo astronauts trained here in the 1960's preparing for
missions to the moon due to scientific predictions as to what the
surface of the moon would be like.
According to information I have read concerning this area, the
age varies from between 80,000 to 200,000 years old. It is part of
the Portillo Volcanic range. This is believed to one of the most
recently active volcanic areas in the southwest.
Here is a listing of the other caches that are in the general
area of this virtual...
Aden's
Crater
G is
For...
Ironwood
Kilbourne's Bighole
Cache
No Shoes...No
Shirt...No Problem
Travis' Unknown
Zone
To log this cache, email me the answer to the following question
as well as posting a photo of you or your group at the site.
Peridot is the gem quality form of what common rock forming
mineral?