<p>Rapidly!</p>
<p>Galle is a large (230km) crater. In the processes that occur in the aftermath of a massive impact, deep rocks can be pushed up. Often this creates a central peak, but it can also form a ring structure, as in this lunar crater:</p>
<p><a href="https://i.sstatic.net/vk7MC.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/vk7MC.png" alt="enter image description here" /></a><br />
<a href="https://en.wikipedia.org/wiki/Schr%C3%B6dinger_(crater)" rel="nofollow noreferrer">Schrödinger</a>, a large (312km) crater, near the south lunar pole.</p>
<p>The <a href="https://www.sciencenews.org/article/how-ring-mountains-forms-inside-crater" rel="nofollow noreferrer">Chicxulub crater</a> also has a similar ring structure. These complex crater structures form very rapidly, in a matter of minutes, as a result of the flow of rocks.  At the pressures and forces which occur in an impact, rock flows like a liquid.</p>
<p>The modelling of complex craters is difficult (it is hard to do an experiment!) but one reasonable model is that the ring forms as a wave generated by the collapse and terracing of the crater walls meets a second wave generated from the centre, as a central peak (which had previous formed) collapses.</p>
<p>The rings, as in the case of Schrodinger, may be incomplete, or reduced to just an arc and a couple of isolated peaks. : )</p>

CC BY-SA 4.0
2021-12-31T14:43:19.743Z
So there were two rings, and the inner one was reduced to an arc from erosion?
usernumber
CC BY-SA 4.0
2021-12-31T15:27:22.833Z
or the inner ring only partially formed, perhaps due to differences in the underlying rocks.  The process of crater formation is incompletely understood.
James K
CC BY-SA 4.0
2021-12-31T10:55:32.080Z
2021-12-31T10:55:32.080Z
James K
<p>In the <a href="https://en.wikipedia.org/wiki/Galle_(Martian_crater)" rel="nofollow noreferrer">Galle crater</a>, there is a mountain range that is shaped like a circle segment that makes it look like a smiley face. How did this mountain range form? Is it a central ring that formed with the crater that then got partially eroded away? Or did it form after the crater? Or something else?</p>

CC BY-SA 4.0
2021-12-31T19:54:32.517Z
Are you asking about Galle on the Moon or Galle on Mars?  https://en.wikipedia.org/wiki/Galle_(lunar_crater)    https://en.wikipedia.org/wiki/Galle_(Martian_crater)
M. A. Golding
CC BY-SA 4.0
2022-01-02T08:48:26.350Z
@M.A.Golding There already is a link in the question to the wikipedia page of the crater I am talking about
usernumber
<geology><crater>
How did the mountain range form in Galle crater?
usernumber
# How did the mountain range form in Galle crater?

(Asked by: username_0 on 2021-12-31)

In the [Galle crater](https://en.wikipedia.org/wiki/Galle_(Martian_crater)), there is a mountain range that is shaped like a circle segment that makes it look like a smiley face. How did this mountain range form? Is it a central ring that formed with the crater that then got partially eroded away? Or did it form after the crater? Or something else?

**Tags:** geology, crater
> **Comments:**
> **username_1**: Are you asking about Galle on the Moon or Galle on Mars?  https://en.wikipedia.org/wiki/Galle_(lunar_crater)    https://en.wikipedia.org/wiki/Galle_(Martian_crater)  
> **username_0**: @M.A.Golding There already is a link in the question to the wikipedia page of the crater I am talking about  

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## 1 answers

### Answer by username_2 on 2021-12-31. Score: 4

Rapidly!

Galle is a large (230km) crater. In the processes that occur in the aftermath of a massive impact, deep rocks can be pushed up. Often this creates a central peak, but it can also form a ring structure, as in this lunar crater:

[![enter image description here](https://i.sstatic.net/vk7MC.png)](https://i.sstatic.net/vk7MC.png)  
[Schrödinger](https://en.wikipedia.org/wiki/Schr%C3%B6dinger_(crater)), a large (312km) crater, near the south lunar pole.

The [Chicxulub crater](https://www.sciencenews.org/article/how-ring-mountains-forms-inside-crater) also has a similar ring structure. These complex crater structures form very rapidly, in a matter of minutes, as a result of the flow of rocks. At the pressures and forces which occur in an impact, rock flows like a liquid.

The modelling of complex craters is difficult (it is hard to do an experiment!) but one reasonable model is that the ring forms as a wave generated by the collapse and terracing of the crater walls meets a second wave generated from the centre, as a central peak (which had previous formed) collapses.

The rings, as in the case of Schrodinger, may be incomplete, or reduced to just an arc and a couple of isolated peaks. : )

> **Comments:**
> **username_0**: So there were two rings, and the inner one was reduced to an arc from erosion?  
> **username_2**: or the inner ring only partially formed, perhaps due to differences in the underlying rocks.  The process of crater formation is incompletely understood.  

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