so many changes in direction...
Posted on 08/29/2014 3:15:01 PM PDT by Brother Cracker
Ending a half-century of geological speculation, scientists have finally seen the process that causes rocks to move atop Racetrack Playa, a desert lake bed in the mountains above Death Valley, California. Researchers watched a pond freeze atop the playa, then break apart into sheets of ice that — blown by wind — shoved rocks across the lake bed.
Until now, no one has been able to explain why hundreds of rocks scoot unseen across the playa surface, creating trails behind them like children dragging sticks through the mud.
“It’s a delight to be involved in sorting out this kind of public mystery,” says Richard Norris, an oceanographer at the Scripps Institution of Oceanography in La Jolla, California, who led the research with his cousin James Norris, an engineer at Interwoof in Santa Barbara, California. The work was published on 27 August in PLoS ONE1.
(Excerpt) Read more at nature.com ...
Rocks on ice wouldn’t leave such a deep impression. The video isn’t very clear, (I wonder if that’s deliberate?) but I see no ice near the rock. I sure hope the scientist who made this ‘discovery’ isn’t a relative of yours...
You have to understand the wind there is pretty intense, up to 70 mph on a regular basis. Even on a nice calm day there was wind out there, much more so that I ever expected.
so many changes in direction...
Isn’t a very good example of the power of wind?
-I sure hope the scientist who made this ‘discovery’ isn’t a relative of yours...
Actually, my relatives preferred their rocks of ice with a little Scotch.
Do you need to stand in the washtub full of ice cubes and water and have your old lady pour snow down the back of your neck again?
A review of the weather data showed that a rare winter storm had dropped about 1 1/2 inches of rain and seven inches of snow on the region in late November. The playa was transformed into a shallow lake where the GPS stones recorded movements on sunny days with light winds following nights of sub-freezing temperatures.
James Norris' photographs put it all in perspective. Panes of ice hundreds of feet across and as thin as 1/4-inch thick blew into rocks. The rocks slid along the slushy, slippery mud on trajectories determined by the direction and velocity of the winds.
Desert claypan mud has little structral strenght
-do love a good mystery!
The problem with a good mystery is that when it’s solved it’s no longer a good mystery.
Figure 8. Racetrack Playa phenomena. Parts show: (a) thin windowpane ice over-riding a recently moved rock (January 9, 2014), (b) water creeping onto the low gradient northern shore of the pond during the December 20, 2013 rock movement (~11:15 am), (c) ice windrows on the eastern shore of Racetrack Playa near the weather station (~1 pm, December 20, 2013); ice panels are ~2–3 mm thick and mixed with mud and rocks scoured from the pond bottom, (d) rock carving a wake through ice that is moving left to right; open rippled water in the foreground (January 9, 2014). Images have been cropped but not otherwise edited. doi:10.1371/journal.pone.0105948.g008
If this theory holds, then it could be scaled up to show how the monoliths used in the erection of Stonehenge were transported by ice and wind from their origins.
Hey, as long as the crappies are biting..
I’ll roll in the snow nekkid if I can fill a bucket full of slkabbers.
LOL! Yeah, you got it bad. Looking forward to it myself... For the first time in a long time.
Up here is mostly perch and pike when the shallow lakes and sloughs freeze over... Once the big ice comes in, then it's whitefish, trout, and kokanee... Always get down to Flathead Lake for some Mackinaw, but that's mostly for the dog.
Why is it that customarily, when in close quarters in an ice house for most of a day, that beans or chili are what is on the stove? The logic of that has always escaped me...
Right, the pressure of a strong wind acting on a flat piece of ice could result in substantial forces being applied to the rocks. I could see the rocks being pushed along in slippery mud by these forces. Probably not big rocks but certainly, or conceivably, smaller rocks. I think their report specifically states that it’s smaller rocks that are moved.
And what’s the alternative theory....aliens?
The rocks are about the size and shape of my Dad’s big Masonic Bible. So they are not “small rocks”. At least if you were tossing them...
And the theory has always been that they slid along the mud when it rained. Like anywhere else out there, the mud would be very fine and slippery. This is the first time I’ve heard the ice sheet theory.
Well I mean Bible sized or smaller as opposed to boulders. I could easily imagine flat pieces of ice subject to strong or even moderate winds being able to generate the kinds of forces that could move smallish rocks across a slippery mud surface.
If this theory holds, then it could be scaled up to show how the monoliths used in the erection of Stonehenge were transported by ice and wind from their origins.>>>>>>>>>>>>>
I could go for a theory that the men and women then poured water to let freeze and slide the monoliths over the frozen water. But I would not say that the theory is a complete explanation for the mystery of the moving rcoks of the desert.
The tracks show they bear too much weight for that to be the complete theory.
Despite the name, death valley is a lively place. :’) Y’know, I think this has been posted before...
I'm inclined to agree...it would appear that any amount of wind and ice facilitate and assist the phenomenon, but are not the entire cause.
Maybe its a process similar to glaciation, a movement that creates small moraines, sort of a mini bulldozer effect.Glaciers are ice that have a melt under them because of presure that facillitates the sliding movement.BUt this is not jhow the rocks move altogether.
Perhaps we do not completely understand how glaciers move
either, or we might know more readily how these stones move.
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