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The Strange Rubbing Boulders of the Atacama
Geological Society of America ^ | October 11, 2011 | Unknown

Posted on 10/11/2011 3:03:04 PM PDT by decimon

Boulder, CO, USA – A geologist's sharp eyes and upset stomach has led to the discovery, and almost too-close encounter, with an otherworldly geological process operating in a remote corner of northern Chile's Atacama Desert.

The sour stomach belonged to University of Arizona geologist Jay Quade. It forced him and his colleagues Peter Reiners and Kendra Murray to stop their truck at a lifeless expanse of boulders which they had passed before without noticing anything unusual.

"I had just crawled underneath the truck to get out of the sun," Quade said. The others had hiked off to look around, as geologists tend to do. That's when Quade noticed something very unusual about the half-ton to 8-ton boulders near the truck: they appeared to be rubbed very smooth about their midsections. What could cause this in a place where Earth's most common agent of erosion — water — is as almost nonexistent?

About the only thing that came to mind was earthquakes, said Quade. Over the approximately two million years that these rocks have been sitting on their sandy plain perhaps they were jostled by seismic waves. They caused them gradually grind against each other and smooth their sides. It made sense, but Quade never thought he’d be able to prove it.

Then, on another trip to the Atacama, Quade was standing on one of these boulders, pondering their histories when a 5.3 magnitude earthquake struck. The whole landscape started moving and the sound of the grinding of rocks was loud and clear.

(Excerpt) Read more at geosociety.org ...


TOPICS: History; Science
KEYWORDS: atacama; boulders; california; deathvalley; geology; mysterysolved; racetrackplaya; rocks

1 posted on 10/11/2011 3:03:07 PM PDT by decimon
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To: decimon

That would be kind of cool to see in action.


2 posted on 10/11/2011 3:09:44 PM PDT by cripplecreek (ALCS/NLCS playoff thread http://www.freerepublic.com/focus/f-chat/2789907/posts)
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To: cripplecreek
Apparently, you have to have a case of Montezuma's Revenge, lay down under a truck, and wait for an earthquake.

I think I'll just take the guy's word for it. ;)

/johnny

3 posted on 10/11/2011 3:12:15 PM PDT by JRandomFreeper (gone Galt)
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To: decimon; Miss Marple; cpdiii; geologist; thackney

Geologist bump


4 posted on 10/11/2011 3:12:49 PM PDT by CPT Clay (Pick up your weapon and follow me.)
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To: decimon

Remarkable. I wonder if the same thing can be found in CA with similar frequency of earthquakes?


5 posted on 10/11/2011 3:12:57 PM PDT by JimSEA (The future ain't what it used to be.)
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To: decimon
I thought this might end up being something like what happens at The Racetrack in Death Valley...


6 posted on 10/11/2011 3:15:09 PM PDT by who_would_fardels_bear
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To: JimSEA

Yes, the sides of the heads of California’s lunatic legislator-rockheads have all been worn smooth. However, there is little danger of any brains leaking out.


7 posted on 10/11/2011 3:15:29 PM PDT by Hebrews 11:6 (Do you REALLY believe that (1) God is, and (2) God is good?)
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To: who_would_fardels_bear
That is interesting. Any backstory on how that rock came to be there with that track?

/johnny

8 posted on 10/11/2011 3:17:09 PM PDT by JRandomFreeper (gone Galt)
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To: SunkenCiv

On the rocks ping.


9 posted on 10/11/2011 3:18:00 PM PDT by decimon
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To: decimon
"Quade said. "How do you erode a landscape that is rainless?"

Wind blown sand comes to mind. Note the ripples in the sand in the pics. His example pics also were mostly spaced apart rocks.

10 posted on 10/11/2011 3:18:20 PM PDT by Deaf Smith
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To: decimon

I remember when an earthquake hit my area a year or so ago. I didn’t feel any vibration, but heard a rumbling/roaring kind of sound which I knew had to be a quake (didn’t sound like anything else, for one thing), and it was. It was all the rocks rattling along their joint planes and other fractures.


11 posted on 10/11/2011 3:22:33 PM PDT by hellbender
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To: JRandomFreeper
The best theory is that the dry lake bed becomes more slippery during wetter times and that the winds can then push the rocks along slowly but surely.

Many people have gone out there, some even living out there for short spells. I don't think anyone has actually seen a rock move, but I could be wrong about that.

12 posted on 10/11/2011 3:22:40 PM PDT by who_would_fardels_bear
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To: decimon

http://photojournal.jpl.nasa.gov/catalog/pia04997
Mars seems to have them too.


13 posted on 10/11/2011 3:44:13 PM PDT by Deaf Smith
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To: who_would_fardels_bear

“The Racetrack in Death Valley...”

My first thought as well.


14 posted on 10/11/2011 3:49:15 PM PDT by beelzepug ("Blind obedience to arbitrary rules is a sign of mental illness")
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To: JRandomFreeper

Read a different theory couple months back that frost/condensation was enough to freeze around the rock at night and cause “expansion” in the soil up to about an inch into the soil hence moving the rock (very, very) a little at a time. Still doesn’t explain why one direction is usually observed however..


15 posted on 10/11/2011 3:53:45 PM PDT by Michael Barnes (Obamaa+ Downgrade)
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To: JRandomFreeper

Poltergeists


16 posted on 10/11/2011 4:05:18 PM PDT by Darteaus94025
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To: decimon
Mysterious Moving Coffins
17 posted on 10/11/2011 4:15:57 PM PDT by Oatka ("A society of sheep must in time beget a government of wolves." –Bertrand de Jouvenel)
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To: Oatka
Mysterious Moving Coffins

A zombie with a sense of humor.

18 posted on 10/11/2011 4:23:07 PM PDT by decimon
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To: decimon

Bump for reference. Interesting....


19 posted on 10/11/2011 4:48:23 PM PDT by MeneMeneTekelUpharsin (Freedom is the freedom to discipline yourself so others don't have to do it for you.)
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To: decimon
Boogie Boulders! ...cool
20 posted on 10/11/2011 4:58:06 PM PDT by tophat9000 (American is Barack Oaken)
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To: decimon

“the average boulder has experienced 50,000 to 100,000 hours of bumping and grinding while waiting for that nonexistent train.”

Well, at least they have something to keep them busy. Naughty boulders.


21 posted on 10/11/2011 5:02:19 PM PDT by Squeeky ("Truth is so rare that it is delightful to tell it. " Emily Dickinson)
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To: Michael Barnes

The condensation under a rock on the flat is influence by the direction the sun rises and the nearness of a land rise such as seen behind the rock in the picture. The condensation reduces the coefficient of friction of the rock on the flats soil and the weight of the rock effects the size of the ‘channel walls’, up to a point sustainable by the formation of cie crystals in the condensation enriched soil. ... The side-walls will be noticeable but never high no matter how large the bolder etching the channel.


22 posted on 10/11/2011 5:05:39 PM PDT by MHGinTN (Some, believing they can't be deceived, it's nigh impossible to convince them when they're deceived.)
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To: Michael Barnes
The condensation under a rock on the flat is influence by the direction the sun rises and the nearness of a land rise such as seen behind the rock in the picture ... thawing is related to amount and direction of suns rays. The condensation reduces the coefficient of friction of the rock on the flats soil and the weight of the rock effects the size of the ‘channel walls’, up to a point sustainable by the formation of ice crystals in the condensation enriched soil. ... The side-walls will be noticeable but never high no matter how large the bolder etching the channel.
23 posted on 10/11/2011 5:06:47 PM PDT by MHGinTN (Some, believing they can't be deceived, it's nigh impossible to convince them when they're deceived.)
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