Mystery Of Death Valley's Moving Rocks Finally Solved

Post Reply
Inyo
Posts: 14
Joined: Sun Jan 16, 2011 8:11 am
anti-spam detector: No
The middle number please (4): 4

Mystery Of Death Valley's Moving Rocks Finally Solved

Post by Inyo »

Yes, indeed. It's been solved, finally--how the mysterious sliding rocks of Death Valley National Park are propelled across the world-famous Racetrack Playa (northern sector of the vast desert park, formerly Death Valley National Monument, now with the assimilation of adjacent Wilderness lands in 1994 larger than the entire state of Connecticut).

Check out https://scripps.ucsd.edu/news/mystery-s ... first-time for the answers. While the actual scientific paper that documents with detailed specificity the discoveries has been embargoed pending formal publication in the appropriate professional scientific journal, the above link nevertheless provides a splendid general overview of the study. Be sure to click on the two videos over at the right of the text. Observe in time-lapse photography a rock actually moving across Death Valley's Racetrack Playa.

There are now two known explanations to account for the Racetrack moving rocks: (1) pebble-sized stones that leave behind trails in the mud float out onto the playa on rafts of ice (a scenario long-suspected, of course, but never definitively proved, though this specific method admittedly accounts only for the diminutive rocks, not the dramatic larger specimens that also create trails); and (2) for the larger rocks, the basic idea is that combined with a rare, substantial precipitation event over the playa, providing adequate rainfall to engulf, but not submerge the rocks scattered across the playa, you also need necessary freezing temperatures at night, just low enough to create thin, mere sheets of ice only a few millimeters thick.

Next, comes the morning--and, LIVE ACTION, indeed. What happens next is that you need a sun warm enough to partially melt the ice sheets that have formed around the perimeters of individual rocks: that is to say, sunlight preferentially heats the dark-colored stones to melt all ice in direct contact with them.

Yet, simultaneously, as ice gradually melts out on the playa, temperatures must remain moderately low enough to allow those now separating ice sheets to persist in patches, never entirely disappearing--so that when even rather mild wind gusts occur, the now isolated thin ice sheets begin to move, pushing against neighboring stationary playa rocks, eventually ramming the rocks, causing the stones to move ever so slowly--so slowly, in fact, that the researchers remark that you could be standing right next to one and probably never even notice that it's actually in motion; indeed, they postulate than perhaps several individuals during the historical past have actually been present when the rocks move under such restrictive weather conditions, yet could never detect the activity.

In conclusion, the investigators speculate that such a relatively rare combination of meteorological events conspires to slide the Racetrack Playa rocks no more than once every ten years.

http://inyo.coffeecup.com/site/dv/dvfossils.htm
My page, "Fossils In Death Valley National Park"
User avatar
Space Cowboy
Posts: 213
Joined: Fri Apr 10, 2009 3:59 am
The middle number please (4): 7

Re: Mystery Of Death Valley's Moving Rocks Finally Solved

Post by Space Cowboy »

That's cool.
Post Reply