<p>Per <a href="http://what-if.xkcd.com/94/">yesterday's What-If</a>,</p>

<blockquote>
  <p>If you make a building too big, the top part is heavy and it squishes the bottom part.</p>
</blockquote>

<p>In the context of Tibet, what this means is that rock has a yield strength: pile it up high enough and it will break (via earthquakes); and if you make a big enough pile, especially of continental material, then the concentrations of radiogenic isotopes will be high enough to significantly raise the temperature - and lower the strength - of the rock in question.</p>

<p>In the case of Tibet and the Himalaya, height <em>increase</em> is due to north-south shortening as the Indian plate impacts the Eurasian plate, i.e. the Tibetan plateau initially formed via exactly the same process as the Himalaya. In order to get an approximately stable height, this increase has to be balanced by <em>decrease</em>. The principle processes causing decrease in height in Tibet are:</p>

<ul>
<li>east-west extension (see. e.g. <a href="http://rsta.royalsocietypublishing.org/content/327/1594/379.short">Dewey <em>et al.</em> (1988)</a>, <a href="http://sp.lyellcollection.org/content/19/1/113.short">Tapponnier <em>et al.</em> (1986)</a>), typically along strike-slip faults: this is clearly visible not only in <a href="http://www.geo.arizona.edu/~ozacar/tecton~1.htm">geological maps</a> but also in aerial/satellite photography</li>
<li>erosion rates increase as topography becomes higher, especially in areas of active mountain-building, in part through <a href="http://www.sciencedirect.com/science/article/pii/S0012821X02007252">a change in which erosion processes are favoured</a></li>
</ul>

<p>That the Tibetan plateau is of such uniform height corresponds neatly to calculations suggesting that this is the maximum possible height for such features if they are of typical crustal composition.</p>

CC BY-SA 3.0
2014-05-04T11:35:36.843Z
Neat. Especially the last paragraph :-)
Semidiurnal Simon
CC BY-SA 3.0
2014-04-30T21:40:56.773Z
2014-04-30T21:40:56.773Z
kaberett
<p>Although I basically understand, that how the Himalayas formed, it has always confused me how did the vast high Tibetian Plateau came into existence behind it? And what would be its future, is it expected to remain as such for a long time?</p>

CC BY-SA 3.0
2014-04-25T17:48:00.063Z
I am unsure about the tags, please add them ..
Sawarnik
CC BY-SA 3.0
2014-04-26T01:56:05.527Z
Appears that there might not be a single reason, but many reasons depending on where in the plateau you are looking at; for example, [http://geology.gsapubs.org/content/41/4/439.abstract](http://geology.gsapubs.org/content/41/4/439.abstract)
blunders
CC BY-SA 3.0
2014-04-29T16:57:22.827Z
There's the handwave-y version that says "rates of orogenic growth and rates of erosion eventually balance, because higher things are exposed to more erosion", plus simple issues of rock strength. However, I'm a volcanologist not a structural geologist; nonetheless if you'd like me to expand on this let me know and I'll type something proper up.
kaberett
CC BY-SA 3.0
2014-04-29T17:26:29.980Z
@kaberett Ok :)
Sawarnik
CC BY-SA 3.0
2014-04-30T22:16:57.047Z
I can't recall if crustal delamination is applicable to the whole plateau or not.
Siv
CC BY-SA 3.0
2014-11-18T11:42:30.780Z
This question: http://earthscience.stackexchange.com/q/2827/725 gives a nice link about a new discovery concerning the Himalayas.
Gimelist
<tibetan-plateau><orogeny>
What is the current theory about the formation of Tibet?
Sawarnik
# What is the current theory about the formation of Tibet?

(Asked by: username_0 on 2014-04-25)

Although I basically understand, that how the Himalayas formed, it has always confused me how did the vast high Tibetian Plateau came into existence behind it? And what would be its future, is it expected to remain as such for a long time?

**Tags:** tibetan-plateau, orogeny

> **Comments:**
> **username_0**: I am unsure about the tags, please add them ..  
> **username_1**: Appears that there might not be a single reason, but many reasons depending on where in the plateau you are looking at; for example, [http://geology.gsapubs.org/content/41/4/439.abstract](http://geology.gsapubs.org/content/41/4/439.abstract)  
> **username_2**: There's the handwave-y version that says "rates of orogenic growth and rates of erosion eventually balance, because higher things are exposed to more erosion", plus simple issues of rock strength. However, I'm a volcanologist not a structural geologist; nonetheless if you'd like me to expand on this let me know and I'll type something proper up.  
> **username_0**: @username_2 Ok :)  
> **username_3**: I can't recall if crustal delamination is applicable to the whole plateau or not.  
> **username_4**: This question: http://earthscience.stackexchange.com/q/2827/725 gives a nice link about a new discovery concerning the Himalayas.  

---

## 1 answers

### Answer by username_2 on 2014-04-30. Score: 11 | Accepted answer

Per [yesterday's What-If](http://what-if.xkcd.com/94/),

> If you make a building too big, the top part is heavy and it squishes the bottom part.

In the context of Tibet, what this means is that rock has a yield strength: pile it up high enough and it will break (via earthquakes); and if you make a big enough pile, especially of continental material, then the concentrations of radiogenic isotopes will be high enough to significantly raise the temperature - and lower the strength - of the rock in question.

In the case of Tibet and the Himalaya, height *increase* is due to north-south shortening as the Indian plate impacts the Eurasian plate, i.e. the Tibetan plateau initially formed via exactly the same process as the Himalaya. In order to get an approximately stable height, this increase has to be balanced by *decrease*. The principle processes causing decrease in height in Tibet are:

* east-west extension (see. e.g. [Dewey *et al.* (1988)](http://rsta.royalsocietypublishing.org/content/327/1594/379.short), [Tapponnier *et al.* (1986)](http://sp.lyellcollection.org/content/19/1/113.short)), typically along strike-slip faults: this is clearly visible not only in [geological maps](http://www.geo.arizona.edu/~ozacar/tecton~1.htm) but also in aerial/satellite photography
* erosion rates increase as topography becomes higher, especially in areas of active mountain-building, in part through [a change in which erosion processes are favoured](http://www.sciencedirect.com/science/article/pii/S0012821X02007252)

That the Tibetan plateau is of such uniform height corresponds neatly to calculations suggesting that this is the maximum possible height for such features if they are of typical crustal composition.

> **Comments:**
> **username_5**: Neat. Especially the last paragraph :-)  

---

