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Mosaic-like surface of the Racetrack Playa |
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Sliding stone at the end of its most recent journey |
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Not tire tracks, but evidence of more sliders |
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Sliding stones on the east side of the Playa |
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Very mysterious indeed... |
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While I have seen passenger vehicles of all kinds
out at the Racetrack playa, a truck or SUV with good ground
clearance is the best choice for making the journey. The first
two-and-a-half miles can be very rough and treacherous because
of erosion from spring rain storms, especially for those who
lack off-highway travel expertise. Regardless of vehicle type,
it's also wise to lower tire pressures to a range of 20 to
25 psi (depending upon the type and condition of the tires).
Lowering air pressure allows tires to "float" over
sharp stones and sandy places and also increases the "footprint"
of the tires which increases traction. Of course, upon return
to the hard paved road, tires must be reinflated for safe
travel on the highway. I use compressed CO2 in a Power
Tank for this task, but inexpensive DC-powered air compressors
work fine, too. Failure to lower tire pressure can lead to
shredded tires, broken steering assemblies, not to mention
a very uncomfortable ride.
After "airing-down" my tires to 22
pounds, I headed down the trail. It's a very bumpy twenty-six
miles of washboard and sharp rocks to Tea Kettle Junction.
I don't how long people have been hanging tea kettles on the
sign there, but the array and the notes are great fun to look
at. The Park Service polices this junction and keeps the "contributions"
to a pleasing number. [Here
are some photos dating back several years, showing the ebb
and flow of tea kettle art.] From Teakettle Junction,
the route to the southeast crosses through Lost Burro Gap
(a gorgeous "secret passage" to Hidden Valley) and
eventually to Hunter Mountain Road and down into the Saline
Valley. The limestone rock found in the area around Lost Burro
Gap is full of fossils, and we have also seen many Indian
petroglyphs and other ancient rock graffiti.
But our mission today was to continue towards
the southwest on Racetrack Valley Road another six miles to
the edge of the dry lake bed. At the first parking area, we
walked out to the impressive basalt intrusions known as "Th
Grandstand," where we began to see some of the tracks
left by sliding stones. No one really knows for sure what
the mechanism is that causes these stones weighing as little
as a few ounces or as much as 300 pounds to begin their mysterious
and sometimes circuitous slides across the playa, but plenty
of scientists and amateur geologists have come to this isolated
lake bed and formed theories. Some have postulated that the
movement is caused by a combination of triple-digit winds,
ice sheets and slippery mud. Scientists like to use terms
like "threshold coefficients of static friction,"
but the rest of us can more easily relate to terms like "slicker
than snot." To date, no one has actually witnessed the
stones moving. This is in part because when the extreme weather
conditions that could lead to movement occur, no human wanting
to stay healthy and alive should be anywhere nearby.
Most of the sliding stones can be found at the
extreme southern end of the lake bed, where there is another
parking area about six miles south of the first one. To see
the best stones requires a fifteen-minute walk (at least)
across the mosaic-like surface of the dry lake.
Some links to the some of the "scientific"
explanations.
Ice
GPS
Analysis
Doctoral
Dissertation by Paula Messina
162
Named Rocks (My personal favorite)
Terry
Moran's Humps
Extreme
Weather is the culprit
Next: The
Lippincot Mine Road>
Mark
Sedenquist
April 23, 2006
