<p>I'm interested in the limiting factors on the height of mountains. There is a very good explanation at <a href="https://www.quora.com/How-tall-can-a-mountain-become-on-Earth-Neil-deGrasse-Tyson-says-Mount-Everest-is-about-as-tall-as-a-mountain-on-Earth-can-grow-%E2%80%9D-but-Mauna-Kea-is-significantly-taller-about-15-than-Everest" rel="nofollow noreferrer">https://www.quora.com/How-tall-can-a-mountain-become-on-Earth-Neil-deGrasse-Tyson-says-Mount-Everest-is-about-as-tall-as-a-mountain-on-Earth-can-grow-%E2%80%9D-but-Mauna-Kea-is-significantly-taller-about-15-than-Everest</a></p>
<blockquote>
<p>The actual lithospheric limit to mountain height averages about half the height of Everest, which is why Fourteeners are so famous in Colorado. Mountains that exceed this limit have local geologic circumstances that make their height possible, e.g. stronger or denser rocks. In the case of Everest and the Himalayas, you have a geologic situation that is very rare in Earth history. The Indian plate is ramming into the Eurasian plate with such force that instead of just wrinkling the crust on either side into mountain ranges it has actually succeeded in lifting the Eurasian plate up on top. So the Himalayas have double the thickness of the average continental plate, thus double the mountain height that would be considered &quot;normal&quot;.</p>
</blockquote>
<p>That seems to make perfect sense, providing a logical explanation for why the Himalayas and Rockies are both the height they are.</p>
<p>But what about the Andes? Chimborazo 6268 m, Cotopaxi 5897 m, Aconcagua 6962 m, all considerably higher than the 14,000 feet (4270 m) suggested to be the normal limit. And this is not a case of two continental plates colliding. It's a continental plate and an oceanic plate, so the explanation that applies to the Himalayas cannot apply here.</p>
<p>How do the Andes manage to be as tall as they are?</p>

CC BY-SA 4.0
2021-05-13T19:32:40.127Z
@Universal_learner No. That derives an order of magnitude estimate from the basic properties of the materials, but says nothing about the quoted argument regarding particular mountain ranges, or why the Andes appear to be an exception.
rwallace
CC BY-SA 4.0
2021-05-13T20:23:17.560Z
@Earthworm I don't know where the Quora poster got it from, but I got it from the Quora post. The argument made by that post, sounds plausible, but I'm not a geologist; is it actually incorrect? And I would definitely like to know how the situation differs when mountains are above a subduction zone.
rwallace
CC BY-SA 4.0
2021-05-14T05:09:20.263Z
https://doi.org/10.1126/science.1148615
Gimelist
CC BY-SA 4.0
2021-05-19T08:42:39.977Z
I do not understand who is saying what, but the original lectures from deGrasse Tyson can be found here:
http://www.infocobuild.com/education/learn-through-videos/astronomy/my-favorite-universe.html
EarlGrey
<geology><geophysics><plate-tectonics><mountains><mountain-building>
How do the Andes get so high?
rwallace
# How do the Andes get so high?

(Asked by: username_0 on 2021-05-13)

I'm interested in the limiting factors on the height of mountains. There is a very good explanation at <https://www.quora.com/How-tall-can-a-mountain-become-on-Earth-Neil-deGrasse-Tyson-says-Mount-Everest-is-about-as-tall-as-a-mountain-on-Earth-can-grow-%E2%80%9D-but-Mauna-Kea-is-significantly-taller-about-15-than-Everest>

> The actual lithospheric limit to mountain height averages about half the height of Everest, which is why Fourteeners are so famous in Colorado. Mountains that exceed this limit have local geologic circumstances that make their height possible, e.g. stronger or denser rocks. In the case of Everest and the Himalayas, you have a geologic situation that is very rare in Earth history. The Indian plate is ramming into the Eurasian plate with such force that instead of just wrinkling the crust on either side into mountain ranges it has actually succeeded in lifting the Eurasian plate up on top. So the Himalayas have double the thickness of the average continental plate, thus double the mountain height that would be considered "normal".

That seems to make perfect sense, providing a logical explanation for why the Himalayas and Rockies are both the height they are.

But what about the Andes? Chimborazo 6268 m, Cotopaxi 5897 m, Aconcagua 6962 m, all considerably higher than the 14,000 feet (4270 m) suggested to be the normal limit. And this is not a case of two continental plates colliding. It's a continental plate and an oceanic plate, so the explanation that applies to the Himalayas cannot apply here.

How do the Andes manage to be as tall as they are?

**Tags:** geology, geophysics, plate-tectonics, mountains, mountain-building

> **Comments:**
> **username_0**: @Universal_learner No. That derives an order of magnitude estimate from the basic properties of the materials, but says nothing about the quoted argument regarding particular mountain ranges, or why the Andes appear to be an exception.  
> **username_0**: @Earthworm I don't know where the Quora poster got it from, but I got it from the Quora post. The argument made by that post, sounds plausible, but I'm not a geologist; is it actually incorrect? And I would definitely like to know how the situation differs when mountains are above a subduction zone.  
> **username_1**: https://doi.org/10.1126/science.1148615  
> **username_2**: I do not understand who is saying what, but the original lectures from deGrasse Tyson can be found here: http://www.infocobuild.com/education/learn-through-videos/astronomy/my-favorite-universe.html  

---

## 0 answers

