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/sci/ - Science & Math


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3960687 No.3960687 [Reply] [Original] [archived.moe]

Sailing stones, sliding rocks, and moving rocks all refer to a geological phenomenon where rocks move in long tracks along a smooth valley floor without human or animal intervention. They have been recorded and studied in a number of places around Racetrack Playa, Death Valley, where the number and length of travel grooves are notable. The force behind their movement is not confirmed and is the subject of research.

>> No.3960695

Bob Sharp and Dwight Carey started a Racetrack stone movement monitoring program in May 1972. Eventually thirty stones with fresh tracks were labeled and stakes were used to mark their locations. Each stone was given a name and changes in the stones' position were recorded over a seven year period. Sharp and Carey also tested the ice floe hypothesis by corralling selected stones. A corral 5.5 feet (1.7 m) in diameter was made around a 3 inches (7.6 cm) wide, 1 pound (0.45 kg) track-making stone with seven rebar segments placed 25 to 30 inches (63 to 76 cm) apart. If a sheet of ice around the stones either increased wind-catching surface area or helped move the stones by dragging them along in ice floes, then the rebar should at least slow down and deflect the movement. Neither appeared to occur; the stone barely missed a rebar as it moved 28 feet (8.5 m) to the northwest out of the corral in the first winter. Two heavier stones were placed in the corral at the same time; one moved five years later in the same direction as the first but its companion did not move during the study period. This indicated that if ice played a part in stone movement, then ice collars around stones must be small.

>> No.3960698

Can it be wind? Smooth valley floors are ideal places for strong winds. It can also account for changing directions.

>> No.3960702

Ten of the initial twenty-five stones moved in the first winter with Mary Ann (stone A) covering the longest distance at 212 feet (65 m). Two of the next six monitored winters also saw multiple stones move. No stones were confirmed to have moved in the summer and some winters none or only a few stones moved. In the end all but two of the thirty monitored stones moved during the seven year study. At 2.5 inches (6.4 cm) in diameter, Nancy (stone H) was the smallest monitored stone. It also moved the longest cumulative distance, 860 feet (260 m), and the greatest single winter movement, 659 feet (201 m). The largest stone to move was 80 pounds (36 kg).

Karen (stone J) is a 29 by 19 by 20 inches (74 by 48 by 51 cm) block of dolomite and weighs an estimated 700 pounds (318 kg). Karen did not move during the monitoring period. The stone may have created its 570 foot long straight and old track from momentum gained from its initial fall onto the wet playa. However, Karen disappeared sometime before May 1994, possibly during the unusually wet winter of 1992 to 1993. Removal by artificial means is considered unlikely due to the lack of associated damage to the playa that a truck and winch would have caused. A possible sighting of Karen was made in 1994 a half mile (800m) from the playa. Karen was rediscovered by San Jose geologist Paula Messina in 1996.

>> No.3960706

>>3960698
"A balance of specific conditions are thought to be needed for stones to move:

a saturated yet non-flooded surface,
a thin layer of clay,
very strong gusts as initiating force, and
strong sustained wind to keep stones going"

So probably yes. Still though, read the paragraph about Karen in my last post

>> No.3960715

I find it hard to believe wind can do this. Sounds like something a scientist says when he has know clue what the fuck is going on.
Put up a big box around one of the fuckers, then we'll see if it's wind or not.

>> No.3960721

>http://www.youtube.com/watch?v=u1hoiHvOeGc
Water is blown across the surface of the desert, freezes, and drags the stones frozen within the ice across the the ground.

>> No.3960725

>>3960706
It's pretty comical how this is described. Thanks for posting it.
>>3960715
>Sounds like something a scientist says when he has know clue what the fuck is going on.
Well, I don't pretend to have a clue. Wind was only my hypothesis (a guess).

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