The nature of the trails recorded by inferred rock movement indicates that motion occurs only when the playa surface is wet, because smooth, rounded levees form and are preserved as "fossil wakes."

All sliding rock traces are ephemeral: the smallest ones may not survive a subsequent rainfall, while others produced by the most massive boulders may last no longer than about seven years (Sharp and Carey, 1976).  Hence, previous monitoring studies and limited-area maps generated may no longer be valid.  Movement appears to be episodic and linked to the occurrence of storms (Sharp and Carey, 1976; Reid et al., 1995).  Major "rock slides" are punctuated by stable periods, coinciding with dry conditions on the playa.

Despite years of interest and intermittent research investigations, no one has ever witnessed the rocks in motion.   The mechanisms for these unusual events have been hypothesized and in some cases tested, but never proven. Gravity must be ruled out, since the rocks are generally moving slightly uphill (the northern section of the playa is a few centimeters higher than the southern end).

This research project evolved from a natural curiosity about this exceptional aeolian process.  It seemed essential to observe the scarred surface in plan view, and to analyze the spatial patterns inscribed by the rocks, particularly in the context of surrounding landforms.  Despite the publication of several papers about this oddity, no complete maps of the Racetrack’s trails were in existence.  Compilation of the first detailed map of the furrows was paramount to a better understanding of the unexplained process responsible for the inferred rock motion.

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