Unless you are camping or have a handicap placard you
must take the shuttle bus down into the valley from Mammoth
Mountain. A fee is required. There is no access during the
winter months. Following the bus ride, there short hike to the
top of the Postpile from the ranger station.
Deep beneath the earth there is still some magma cooling. This
magma may be related to the nearby Long Valley Caldera and Mammoth
Mountain (an active volcano). As magma cools, various gasses are
released. Water vapor is usually by far the most common, then
carbon dioxide, followed by sulfur dioxide. Many other compounds
are also in volcanic gasses, but their composition is individual to
each volcano. The relative composition of the gas released by
cooling magma even changes as it cools. Carbon dioxide is usually
the most common in the last stages of cooling.
As the carbon dioxide encounters ground water at depth, it
dissolves into the ground water creating naturally carbonated
water. At depth, this water is under pressure, but when the water
nears the surface at springs, the pressure is reduced and the
carbon dioxide bubbles out like a carbonated drink that has been
opened.
These springs often have other dissolved minerals in them. At
this spring, references indicate that there is a fair amount of
iron. This mineral precipitates out onto the surrounding rocks
giving them a red iron oxide (rust colored) tinge.
Logging requirements:
Send me a note with :
- The text "GC1FE0J Soda Springs at Devil’s Postpile" on the
first line
- The number of people in your group.
- Watch one of the springs and count the number of bubbles coming
out in a 10 second time frame. Post this answer and we’ll see if it
changes over time.
- Try to identify the iron oxide precipitate to see if you agree
with the references that say there is dissolved iron in the
spring.
The above information was compiled from the
following sources:
- The Devil Postpile National Monument (1952) by
Richard J. Hartesveldt, Yosemite Nature Notes; THE MONTHLY
PUBLICATION OF THE YOSEMITE NATURALIST DIVISION AND THE YOSEMITE
NATURAL HISTORY ASSOCIATION, INC; VOL. XXXXI; NO. 10, OCTOBER,
1952; http://www.yosemite.ca.us/library/devil_postpile/
.
- USGS, Volcano Hazards Program, Volcanic Gases
and Their Effects,
http://volcanoes.usgs.gov/Hazards/What/VolGas/volgas.html
.
Placement approved by permit from the
Devils Postpile National Monument