<p>Over recent geological history sea levels in the Arabian Gulf have fluctuated, leading to periods when sands are laid down, possibly above the shoreline, and periods when, with higher sea levels, carbonates have been deposited. The carbonates are more resistant to erosion and so form the plateau layer. The softer, weakly cemented, sandstones are more easily eroded by wind or wave and this leads to the carbonate layer being undercut. When the carbonate is unsupported it cracks and falls, but as large lumps of rock that litter the bottom of the slope. There are several papers with more detail of the coastal geology and processes in the area, <a href="https://www.researchgate.net/publication/285724202_Pleistocene_carbonate_seif_dunes_and_their_role_in_the_development_of_complex_past_and_present_coastlines_of_the_UAE" rel="nofollow noreferrer">e.g Kirkham, 1998</a>.</p>

CC BY-SA 4.0
2023-06-27T17:49:51.207Z
Hi @Andy! thanks so much for your kind answer.... all clear now! thanks for the suggestions as well. Cheers
Jefferson Gonzalez
CC BY-SA 4.0
2023-06-27T09:06:41.577Z
2023-06-27T09:06:41.577Z
Andy M
<p>I got to about the same idea as Andy M, but weighing the photo evidence slightly differently.</p>
<p>In the main, off-white, section of the exposed face, you can't see any of the the brown, resistant stones. But something similar is visible near the top of the cliff.</p>
<p>Note that the cliff has colour and texture banding parallel to the land surface (before the recent erosion). The band of source material is also parallel to the ground surface.</p>
<p>That looks like the development of a soil structure (in layers, parallel to the ground surface) and in particular a CALCRETE soil where (as Andy M says) carbonate minerals precipitate in the soil to form a hard band. This hard band is then protecting the softer material below from erosion until the hard carbonate blocks topple from the edge of the cliff. The soft material beneath is then rapidly washed away.</p>
<p>The formation of calcrete soils in historical time in the Middle East, particularly in Mesopotamia, has seriously damaged agricultural productivity since the region was the centre of the &quot;Fertile Crescent&quot;. Abu Dhabi is a little distant from this classical (in several senses) example of man wrecking the topsoil he depends on, but has a similar climate.</p>
<p>I remember the Monsoon arriving in Abu Dhabi, while working on a rig there. It went from 38° C and 10% humidity to 35° C and 90% humidity. In one day. Horrible!</p>

CC BY-SA 4.0
2023-07-12T10:38:17.100Z
2023-07-12T10:38:17.100Z
Rockdoctor
<p>I need some help with my grandson's school homework: can someone describe what's the phenomena behind the creation of these small stones at the plateau´s foot? why &amp; how are they created?</p>
<p>No big deal - an answer for dummies would be great!</p>
<p>Thanks in advance to all! Cheers<img src="https://i.sstatic.net/1bCqf.jpg" alt="enter image description here" /></p>

CC BY-SA 4.0
2023-06-24T22:15:18.290Z
If you give the location, it would encourage answers.
f.thorpe
CC BY-SA 4.0
2023-06-25T01:05:54.180Z
Close up pictures of the stones would also help. Some stones look like they could be few stones clumped together or a larger stone dividing into smaller fragments. Close up pictures would help with this.
Fred
CC BY-SA 4.0
2023-06-25T11:32:39.863Z
simple answer: erosion, without more information that's the best you are going to get.
John
CC BY-SA 4.0
2023-06-26T09:24:28.090Z
Scale is hard to tell. Is this in a river valley?
gerrit
CC BY-SA 4.0
2023-06-26T17:49:53.660Z
@f.thorpe: thanks for your answer; location is Abu Dhabi, UAE
Jefferson Gonzalez
CC BY-SA 4.0
2023-06-26T17:50:43.690Z
@Fred Appreciate your comments. Not possible to get a closer picture of the stones. Thanks
Jefferson Gonzalez
CC BY-SA 4.0
2023-06-26T17:51:09.913Z
@John Appreciate your answer... cheers
Jefferson Gonzalez
CC BY-SA 4.0
2023-06-26T17:51:48.650Z
@gerrit: no, it is close to a shore line, north-west Abu Dhabi, UAE
Jefferson Gonzalez
<geology>
How the small stones in this photo are created?
Jefferson Gonzalez
# How the small stones in this photo are created?

(Asked by: username_0 on 2023-06-24)

I need some help with my grandson's school homework: can someone describe what's the phenomena behind the creation of these small stones at the plateau´s foot? why & how are they created?

No big deal - an answer for dummies would be great!

Thanks in advance to all! Cheers![enter image description here](https://i.sstatic.net/1bCqf.jpg)

**Tags:** geology

> **Comments:**
> **username_1**: If you give the location, it would encourage answers.  
> **username_2**: Close up pictures of the stones would also help. Some stones look like they could be few stones clumped together or a larger stone dividing into smaller fragments. Close up pictures would help with this.  
> **username_3**: simple answer: erosion, without more information that's the best you are going to get.  
> **username_4**: Scale is hard to tell. Is this in a river valley?  
> **username_0**: @username_1: thanks for your answer; location is Abu Dhabi, UAE  
> **username_0**: @username_2 Appreciate your comments. Not possible to get a closer picture of the stones. Thanks  
> **username_0**: @username_3 Appreciate your answer... cheers  
> **username_0**: @username_4: no, it is close to a shore line, north-west Abu Dhabi, UAE  

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## 2 answers

### Answer by username_5 on 2023-06-27. Score: 2

Over recent geological history sea levels in the Arabian Gulf have fluctuated, leading to periods when sands are laid down, possibly above the shoreline, and periods when, with higher sea levels, carbonates have been deposited. The carbonates are more resistant to erosion and so form the plateau layer. The softer, weakly cemented, sandstones are more easily eroded by wind or wave and this leads to the carbonate layer being undercut. When the carbonate is unsupported it cracks and falls, but as large lumps of rock that litter the bottom of the slope. There are several papers with more detail of the coastal geology and processes in the area, [e.g Kirkham, 1998](https://www.researchgate.net/publication/285724202_Pleistocene_carbonate_seif_dunes_and_their_role_in_the_development_of_complex_past_and_present_coastlines_of_the_UAE).

> **Comments:**
> **username_0**: Hi @username_5! thanks so much for your kind answer.... all clear now! thanks for the suggestions as well. Cheers  

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### Answer by username_6 on 2023-07-12. Score: 0

I got to about the same idea as username_5 M, but weighing the photo evidence slightly differently.

In the main, off-white, section of the exposed face, you can't see any of the the brown, resistant stones. But something similar is visible near the top of the cliff.

Note that the cliff has colour and texture banding parallel to the land surface (before the recent erosion). The band of source material is also parallel to the ground surface.

That looks like the development of a soil structure (in layers, parallel to the ground surface) and in particular a CALCRETE soil where (as username_5 M says) carbonate minerals precipitate in the soil to form a hard band. This hard band is then protecting the softer material below from erosion until the hard carbonate blocks topple from the edge of the cliff. The soft material beneath is then rapidly washed away.

The formation of calcrete soils in historical time in the Middle East, particularly in Mesopotamia, has seriously damaged agricultural productivity since the region was the centre of the "Fertile Crescent". Abu Dhabi is a little distant from this classical (in several senses) example of man wrecking the topsoil he depends on, but has a similar climate.

I remember the Monsoon arriving in Abu Dhabi, while working on a rig there. It went from 38° C and 10% humidity to 35° C and 90% humidity. In one day. Horrible!


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