Question 35 What causes the movement of the famous sailing rocks at Racetrack Playa? A) Earthquake activity B) Magnetic forces C) Animal migration D) Thin ice layers and wind
Answer (1)
The movement of the famous sailing rocks at Racetrack Playa is primarily caused by thin ice layers and wind . This phenomenon is quite intriguing and had puzzled scientists for many years until recent studies provided a more complete explanation.
Racetrack Playa is a dry lakebed located in Death Valley National Park, California. The rocks, which can weigh several hundred pounds, leave behind long tracks or trails on the otherwise flat, dried mud surface of the playa.
Here's how the phenomenon works step-by-step:
Thin Ice Layers Formation: During winter, a shallow layer of water covers the playa when it rains. On very cold nights, this water freezes to form a thin layer of ice around the rocks.
Ice Melting and Breaking: As the sun rises, the ice melts gradually and starts to crack, breaking into large floating panels.
Wind Influence: When the wind blows across the playa, it pushes these ice panels. Even a gentle breeze, along with the buoyant ice, can provide enough force to slowly move the rocks across the wet and slippery surface.
Track Formation: As the rocks move, they leave trails or tracks on the soft, muddy ground, documenting their journey. These tracks can measure several hundred meters in length.
This explanation was confirmed by a team of researchers in 2013 who used GPS and time-lapse cameras to monitor the rocks' movements. The answer to the multiple-choice question is D) Thin ice layers and wind.
