Saturday, August 18, 2012

The Sailing Stones of Death valley..!!

The Racetrack Playa is a place in Death Valley National Park in California USA. It is a dry lake bed 1130 metres above sea level and some 4.5 Km long. The bed is also incredibly flat with the height differential between the north and south ends being a mere 4cm.When it rains, the dark Dolomite mountains that surround the Racetrack funnel the water onto the lake bed, creating a shallow lake. The incredibly hot temperatures of the area quickly evaporate the lake and cracking the mud to leave a fascinatingly regular mosaic type pattern on the dried lake bed floor.

The track lengths of some of the "Sailing Stones" are incredible.
(Source: wikipedia)

What are "Sailing Stones"?

The lake bed is also home to some rocks - But these aren't just ordinary rocks - These rocks move. Nobody has ever seen them move, and nobody knows how or why they move - but move they do.
They are known as "Sailing Stones", and when they move, they leave trails and tracks behind them, sometimes hundreds of metres long. Occasionally the tracks take the form of furrows which have been gouged out of the surface mud. Sometimes they will move with other rocks in parallel. Sometimes one or more will change direction abruptly and for no apparent reason. Sometimes the lines are as straight as a rule, other times they curve in large majestic sweeps.The rocks are not all tiny tiddlers either. Some Sailing Stones can weigh as much as a man. the weight of the individual rocks, or the resistance of the surface they are travelling on seems to have no effect on the Sailing Stones ability to move, or the distance they can cover.

"Sailing Stones" Movements

Sailing Stones seem to move only every couple of years, and the courses of the individual tracks can take a number of years to develop. The tracks have no standard direction or length, and the paths of different rocks often cross.Occasionally Sailing Stones will even turn over during their travels, as evidenced by the changes in the tracks they leave behind. Sometimes, two rocks that are similar in weight and size will travel together as "companions" before one rock inexplicably stops and lets it's companion travel on alone.

"Sailing Stones" Theories

One theory suggested by geologists was that Sailing Stones moved by the action of the wind when the ground was still muddy after a deluge. But this does not take into account the fact that the rocks do not all travel in the same direction (which one would assume to be the case if they being pushed by wind), and that they also travel at the height of summer when the ground is baking dry.One of the largest "Sailing Stones" to be studied by geologists was given the name "Karen". This was a 29 by 19 by 20 inch lump of Dolomite weighing 700 pounds that had created a straight track 570 feet long on the dry lake bed. When geologists went to check on Karen in May 1974, they were surprised to discover that the rock had just disappeared!There was no way that the rock could have been stolen or moved artificially because the truck needed to do so would have left it's marks in the soft lakebed surface.A sighting of Karen was claimed to have been made in 1994 some 800 metres away from the playa. The stone was eventually found in 1996 by San Jose Geologist Paul Messina.

And so the mystery of the "Sailing Stones" continues. While theories and guesses about this strange phenomenon abound, it is safe to say that nobody really knows - because nobody has ever seen them move.