We suggest that the existence of many of the rock-carved trails at Racetrack Playa in Death Valley National Park is predominantly due to the effect of arbitrarily weak winds on rocks that are floated off the soft bed by small rafts of ice, as also occurs in arctic tidal beaches to form boulder barricades. These ice cakes need not have a particularly large surface area if the ice is adequately thick—the ice cakes allow the rocks to move by buoyantly reducing the reaction and friction forces at the bed, not by increasing the wind drag. The parameter space of ice thickness and extent versus rock size for flotation is calculated and found to be reasonable. We demonstrate the effect with a simple experiment.
REFERENCES
1.
M. B.
Miller
, “Geological landscapes of the Death Valley Region
,” Earth-Sci. Rev.
71
, 17
–30
(2001
).2.
L. G.
Kirk
, “Trails and rocks observed on a playa in Death Valley National Monument, California
,” J. Sediment. Petrol.
22
, 173
–181
(1952
).3.
R. P.
Sharp
, “Sliding stones, Racetrack Playa, California
,” Geol. Soc. Am. Bull.
87
, 1704
–1717
(1976
).4.
J. B.
Reid
, E. P.
Bucklin
, L.
Copenagle
, J.
Kidder
, S. M.
Pack
, P. J.
Polissar
, and M. L.
Williams
, “Sliding rocks at the Racetrack, Death Valley: What makes them move?
,” Geology
23
, 819
–822
(1995
).5.
P.
Messina
and P.
Stoffer
, “Terrain analysis of the Racetrack Basin and the sliding rocks of Death Valley
,” Geomorphology
35
, 253
–265
(2000
).6.
S. A.
Schumm
, “The movement of rocks by wind
,” J. Sediment. Petrol.
26
, 284
–286
(1956
).7.
G. M.
Stanley
, “Origin of playa stone tracks, Racetrack Playa, Inyo County, California
,” Geol. Soc. Am. Bull.
66
, 1329
–1350
(1955
).8.
P.
Messina
, “The sliding rocks of Racetrack Playa, Death Valley National Park, California: Physical and spatial influences on surface processes
,” Ph.D. thesis, City University of New York
, 1988
(available at ⟨geosun.sjsu.edu/paula/rtp/dissertation/toc.htm⟩.9.
T.
Clements
, “Wind-blown rocks and trails on Little Bonnie Claire Playa, Nye County, Nevada
,” J. Sediment. Petrol.
22
, 182
–186
(1952
).10.
11.
E.
Wehmeier
, “Water induced sliding of rocks on playas: Alkali flat in Big Smoky Valley, Nevada
,” Catena
13
, 197
–209
(1986
).12.
D.
Bacon
, T.
Cahill
, and T. A.
Tombrello
, “Sailing stones on Racetrack Playa
,” J. Geol.
104
, 121
–125
(1996
).13.
R. D.
Lorenz
, A.
Behar
, F.
Nicaise
, J.
Jonsson
, and M.
Myers
, “Field testing and dynamic model development for a Mars Tumbleweed rover
,” Proceedings of the Fourth International Planetary Probe Workshop
, Pasadena, CA, 25–29 June 2006
, ⟨ippw.jpl.nasa.gov/WORKSHOP/WorkshopProceedings/⟩.14.
R. D.
Lorenz
, B.
Jackson
, and J.
Barnes
, “Inexpensive time lapse digital cameras for studying transient meteorological phenomena: Dust devils and playa flooding
,” J. Atmos. Ocean. Technol.
27
, 246
–256
(2010
).15.
C. L.
Sainsbury
, “Wind-induced stone tracks, Prince of Wales Island, Alaska
,” Bull. Geol. Soc. Am.
67
, 1659
–1660
(1956
).16.
17.
P. S.
Rosen
, “Boulder barricades in Central Labrador
,” J. Sediment. Petrol.
49
, 1113
–1124
(1979
).18.
S.
Byrne
(private communication, 2009
).19.
J.
Stefan
, “Über die Theorie der Eisbildung, insbesondere über die Eisbildung im Polarmeere
,” Ann. Phys.
278
, 269
–286
(1891
).© 2011 American Association of Physics Teachers.
2011
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