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No. 114: Nov-Dec 1997

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The world's largest "playa-slider" furrow

Most studies of playa sliders ("moving rocks") have been conducted at Racetrack Playa, near Death Valley, California. There one finds good-sized rocks at the ends of long tracks they have made when some force has propelled them across the flat playa surface. What has moved these rocks, some of which weigh 700 pounds? The current consensus holds that wind is the motive force, but that it is inadequate to move the rocks directly. Instead, the wind acts upon sheets of ice in which the rocks are frozen. As these sheets of ice are moved across the playa, the keels of the frozen-in rocks leave those curious trails that have intrigued Forteans for many decades. (SF#109)

Playa sliders have also been found at Magdalenasmeer Playa in South Africa, and in Nevada and Tunisia. In a recent issue of Geology Today, C.C. Reeves, Jr., Texas Tech University, adds to the list a playa at Double Lakes, Texas.

Of special interest at Double Lakes is not the rocks and other debris blown across the playa but a discarded hotwater tank. It, too, is a playa slider. It first left a trail a few hundred meters long when it was frozen in an ice sheet spigot down, with the spigot furrow quite obvious. The ice sheet then melted, and the tank was blown over spigot-up. Another ice sheet formed, and the tank was off across the playa again. This time the keel of the tank excavated a furrow as wide as the tank's length, 91 centimeters, several centimeters deep, and 122 meters long. Reeves contends that this is the world's largest playaslider furrow!

(Reeves, C.C., Jr.; "Unusual Playa Sliders at Double Lakes, Texas," Geology Today, 12:207, 1996.)

Comment. Now that science has finally stooped to study this mundane phenomenon and has come up with some answers, we are inclined to remove it from the rolls of Fortean phenomena!

From Science Frontiers #114, NOV-DEC 1997. 1997-2000 William R. Corliss

Science Frontiers Sourcebook Project Reviewed in:

Quotes

  • "A sourcebook of unexplained phenomena is therefore a valuable addition to a collection of scientific literature. William R. Corliss has provided this in the past with his source books of scientific anomalies in several subjects, and now he has provided it for astronomy. He has done an excellent job of collecting and editing a large amount of material, taken in part from scientific journals and in part from scientific reporting in the popular or semi-scientific press." -- "The Mysterious Universe: A Handbook of Astronomical Anomalies", reviwed by Thomas Gold, Cornell University, in Icarus, vol.41, 1980

  • "An interesting, systematic presentation of unusual weather [..] This book is recommended for a general audience" --"Corliss, William R., Tornados, Dark Days, Anomalous Precipitation, and Related Weather Phenomena, Sourcebook Project, 1983.", revieweed in Choice, September 1983
  • "..the science is necessarily somewhat speculative, but Corliss's symthesis is based on reputable sources." -- "Corliss, William R. (Compiler). Lightning, Auroras, Nocturnal Lights, and Related Luminous Phenomena" reviwed by Joseph M. Moran, Univ. of Wisconsin in Science Books and Films, Sep/Oct 1983

  • "Before opening the book, I set certain standards that a volume which treads into dangerous grounds grounds like this must meet. The author scrupulously met, or even exceeded those standards. Each phenomenon is exhaustively documented, with references to scientific journals [..] and extensive quotations" -- "Book Review: The moon and planets: a catalog of astronomical anomalies", The Sourcebook Project, 1985., Corliss, W. R., Journal of the Royal Astronomical Society of Canada, Vol. 81, no. 1 (1987), p. 24., 02/1987