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During a nature walk inside an old abandoned quarry I stumbled upon strange spirals that appear to be naturally formed.

What could cause this spiral formation? Is it a known phenomena?

Earth spiral 1

Earth spiral 2

To clarify , the images are from the same place , but made with difference of couple of days. I took the photos during Winter time in Israel.
The Quarry was abandoned decades ago, so i don't think that this is a result of the working equipment.

Also i have been looking at photos of crop circles but it looks like the two are not related.

Alexander
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  • Welcome to EarthScience.SE! I am not sure whether this question is actually in the scope of Earth Science. It might fit better to Biology.SE? – daniel.heydebreck Oct 26 '17 at 21:19
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    @daniel.neumann There are geological features which can control vegetation growth patterns on the surface, so I think it's plausibly in scope. Hard to tell before we actually know the answer, of course :). – Pont Oct 26 '17 at 21:31
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    Had trouble telling, are these indeed pictures of two separate occurrences? Seems some of the features somewhat lineup, but tough to be certain they're the same. You used the wording "a spirals", which could go either way. If they are two separate occurrences, interesting how the path cuts through both at about the same relative location. Important? – JeopardyTempest Oct 27 '17 at 00:53
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    I agree with @Pont that this question is in scope. – gerrit Oct 27 '17 at 10:03
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    What was being quarried? I suspect this was produced by equipment while the quarry was still active. – Spencer Oct 28 '17 at 00:04
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    Anything about the kind of quarry? That or its name may give us clues about the way material was dug/brought out. You are also not telling us what part of the quarry you took these photos. Please [edit] your question. – Jan Doggen Oct 29 '17 at 18:51
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    Dod Law Quarry Site - Bronze Age Carved Rock – Keith McClary Oct 29 '17 at 20:24
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    Maybe it used to be a pole in the center and a goat tied to a rope. As the goat is grazing around the pole it's winded up and get shorter. If the goat is often tied to the same place it might stick to the same spiral path? (Or some similar process, maybe a dog with a chain scratching the ground or something that is tied to a pole but blow around in the wind.) – user2821 Oct 29 '17 at 21:14
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    Would be pleased to see more pictures of the wider area and/or info on what kind of quarry/where you were too. Also interested... are they actually spirals, or concentric circles? Hard to be sure. – JeopardyTempest Oct 30 '17 at 01:02
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    The Quarry is very old , looks like it was abandoned 20 ~ 30 years ago maybe more, i guess they where quarrying rocks . I will try to get to the place and take larger images of the area. – Alexander Oct 30 '17 at 07:34
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    I believe this to be a mechanical effect perhaps due to a piece of tracked equipment spinning on the locked track. It appears that the organic soil layer has been removed in the spiral and the grass is only growing where there is sufficient solution. Difficult to see if it is truly a spiral or whether it is distorted concentric circles. –  Nov 01 '17 at 19:24
  • It's interesting, and if you have time to make quadrants with squares of string and to draw the exact pattern on paper, you could measure it and have a better chance of finding the cause. – bandybabboon Nov 02 '17 at 18:51

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I came across this photo from Mount Calavera, San Diego County, California. It is described as rock art and is also found in the floor of a quarry. The spiral pattern, including the vegetation, is very similar to your photo. In your photo it looks like the rocks have just been removed.

enter image description here

Rocks appear to affect the soil moisture available for vegetation by shading. From a study in Southwest China investigating the influence of bare rocks on soil moisture:

•We found that bare rocks influenced the surrounding soil moisture by shading.

•The effect degree of rocks to surrounding soil moisture correlated with its shape.

•Soil moisture on the north side of the rocks was significantly higher than others.

•The location at 15 cm north of the rocks was ideal site for plantation restoration.

Source: http://www.sciencedirect.com/science/article/pii/S0341816213003123

Is it possible that rocks used to be placed in a spiral pattern in your photo that allowed the vegetation to take hold?

  • This one is caused by humans manually piling rocks to make shapes. you – Spencer Nov 04 '17 at 23:25
  • @Spencer: Yes, it is caused by humans manually piling rocks. But by manually piling rocks they are, likely inadvertently, increasing soil moisture in the shadows of the rocks. –  Nov 05 '17 at 01:14
  • My comment was much longer than that, but somehow it got lost! The point was that your example is probably not comparable to OP's -- if you look at Google Earth in the vicinity of this "geoglyph" you'll see several others: hearts, the word "GOD", and other whims of the creator. – Spencer Nov 05 '17 at 15:20
  • Nothing in OP's photo gives us any evidence that somebody once piled rocks there. Until OP gives us more information about the site, we have to assume it's a leftover from the industrial activity that went on there. I too am in the "rolled hose" camp until I see something to convince me otherwise. – Spencer Nov 05 '17 at 15:25
  • @Spencer: It looks like the rest of your original post was attached to another answer somehow. I appreciate your opinion and due understand that the rocks placed in this area are created on the whims of the creator. I just found it very interesting that vegetation was only growing near the rocks, in a spiral pattern, in the photo I provided. I provided some additional information to possibly explain how this occurs and do appreciate any discussions. I agree that without more information from the OP, we may never know. –  Nov 05 '17 at 15:41
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You have two options ice segregation/frost heaving or humans screwing around.

Frost heave can produce some really unusual yet regular shapes, spirals included. Frost heave and ice segregation is when freezing ground water pushes more on larger rocks sorting them out of finer material.

Humans messing around can leave spirals intentionally (crop circles, environmental artists) or unintentionally (tethered animals, cropmarks, storing large diameter hose). Given it is a quarry it would not surprise at all if a rolled up air or suction hose was sitting there long enough to alter the sediment or vegetation and we are seeing the marks left over after it was moved.

John
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Given that it's a quarry then at a guess the grass is growing over areas that are cut into the bedrock more deeply than the non-grassed areas, this means that there is a trench that holds a little more soil and water than the relatively bare rock outside of the cuts like a cropmark but smaller and more extreme.

Ash
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  • That's a good thought, but why would anybody cut a quarry in a circular pattern? – userLTK Nov 04 '17 at 19:09
  • @userLTK I figured it was the turning footprint of a tracked vehicle of some sort, the tracks would cut shallow gouges into the rock every time the vehicle made the turn. – Ash Nov 06 '17 at 09:57