Have you ever heard of Racetrack Playa? My guess is probably not. But that’s not the real surprise. A dried up lake located in Death Valley National Park has quite an interesting mystery. There are rocks that slide along the flat dried up land. No one has ever seen them moving in action. However, there is proof of many of these rocks of all sizes that leave a trail along the ground. There are previous and current studies going on to understand this phenomenon.
Death Valley National Park is located in Death Valley, CA. This playa, which is a dried up lake, is about 4 kilometers long and 2 kilometers wide. The ground is immensely flat. The ground type is made up of all clay and silt, with hexagonal mud cracks covering the whole area. This place only gets about 3 to 4 inches of rain per year. When rain does come, the ground becomes a thin layer of slippery mud.
How do these rocks move? That is what scientist and geologists have been trying to understand. There are a few solid explanations that are possible.
The first possible explanation is the wind. Death Valley can get wind speeds of up to 90 miles per hour. The winds move southwest to northwest and most of the rocks slide parallel to this direction. Wind is definitely a factor for the moving rocks.
Another explanation might be humans or animals. But there is visual evidence that disputes this claim. Pictures taken show absolutely no tracks related to living beings.
There happens to be one more possible explanation. As rain comes it yields a slick mud surface. With the winds help to push the rock in motion the mud will let it slide.
I put my money on the wind moving these rocks alone. Since no one has seen or recorded the rocks moving, my best judgment has to go with the wind being the critical factor.
Sliding rocks in Racetrack Playa relate to Earth Science in many ways. We just studied rocks last week and this week we have been studying different types of soil. The silty clay ground makes it very dry and dusty. This phenomenon deals with the earth’s terrain and the rocks on it. I think this is a very interesting mystery. I hope we find out soon how these really move.
by: DAN GASAPO
http://geology.com/articles/racetrack-playa-sliding-rocks.shtml
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