<p>I have run across many pictures of rocks that look like almost perfectly carved columns. For example: the Twyfelfontein Organ Pipes, the Basaltic Prisms of Santa Maria Regla, and the waterfall Svartifoss (pictures included on this link: <a href="http://www.touropia.com/natural-rock-formations/" rel="nofollow noreferrer">http://www.touropia.com/natural-rock-formations/</a>). All of the rocks I have seen that look like this have been basaltic. Is this shape caused more by how the rock originally formed, its mineralogy, or how the rock was eroded?</p>

CC BY-SA 3.0
2017-01-29T06:43:21.513Z
You are asking too much with one question - each formation has it own story & one simple answer doesn't fit all of them. The columnar structure of basaltic organ pipes is due to there mineralogy & how they cooled. Wave Rock is an exposed granite dome that has eroded by water running of the top of the dome & largely down one side of the dome to form its current shape - it's much smaller that pictures of it suggest. The sedimentary formations & pillars have their appearances due to erosion.
Fred
CC BY-SA 3.0
2017-01-29T06:46:03.687Z
For the columnar basalt, see [Giant's Causeway geology](http://earthscience.stackexchange.com/q/4881/725) and [Basalt vs. columnar basalt](http://earthscience.stackexchange.com/q/7981/725). As this is basically the same rock formation (just elsewhere in the world) I am voting to close this as duplicate.
Gimelist
CC BY-SA 3.0
2017-01-29T18:36:00.647Z
https://www.youtube.com/watch?v=c3TpGtUZEjc
MaxW
CC BY-SA 3.0
2017-01-29T18:45:08.970Z
https://www.sciencedaily.com/releases/2008/12/081216104325.htm
MaxW
<geology><mineralogy><erosion><igneous>
What processes cause basalt to form a columnar structure?
Kristina L
# What processes cause basalt to form a columnar structure?

(Asked by: username_0 on 2017-01-29)

I have run across many pictures of rocks that look like almost perfectly carved columns. For example: the Twyfelfontein Organ Pipes, the Basaltic Prisms of Santa Maria Regla, and the waterfall Svartifoss (pictures included on this link: <http://www.touropia.com/natural-rock-formations/>). All of the rocks I have seen that look like this have been basaltic. Is this shape caused more by how the rock originally formed, its mineralogy, or how the rock was eroded?

**Tags:** geology, mineralogy, erosion, igneous

> **Comments:**
> **username_1**: You are asking too much with one question - each formation has it own story & one simple answer doesn't fit all of them. The columnar structure of basaltic organ pipes is due to there mineralogy & how they cooled. Wave Rock is an exposed granite dome that has eroded by water running of the top of the dome & largely down one side of the dome to form its current shape - it's much smaller that pictures of it suggest. The sedimentary formations & pillars have their appearances due to erosion.  
> **username_2**: For the columnar basalt, see [Giant's Causeway geology](http://earthscience.stackexchange.com/q/4881/725) and [Basalt vs. columnar basalt](http://earthscience.stackexchange.com/q/7981/725). As this is basically the same rock formation (just elsewhere in the world) I am voting to close this as duplicate.  
> **username_3**: https://www.youtube.com/watch?v=c3TpGtUZEjc  
> **username_3**: https://www.sciencedaily.com/releases/2008/12/081216104325.htm  

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## 0 answers

