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I am curious as to what physical geographic features would be present on a plateau 10km above sea level. The Tibetan plateau is only 4km above sea level, so would more than doubling the height exaggerate the geographic features we already see in Tibet, or would new and strange climates and temperature start to form?

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  • $\begingroup$ Welcome to worldbuilding. Your question is pretty unclear: the title asks for several things, while the body for something completely different. Can you clarify? You can take the tour and visit the help center for guidance. $\endgroup$ – L.Dutch Jan 22 at 13:04
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    $\begingroup$ Please, try to put 1 question per post. Your edits are making the question too broad. $\endgroup$ – L.Dutch Jan 22 at 13:08
  • $\begingroup$ Welcome to the site, John. Please note that the Worldbuilding SE is dedicated to providing detailed answers to specific questions you have while developing your fictional world. As is, this question is asking several different, unrelated things: geography, climate, and evolution. I would suggest editing to reduce your area of interest in this post to just geography, then asking follow-up questions for the other two subjects. This may be closed as too broad. Feel free to take the tour and check out our site culture. $\endgroup$ – Frostfyre Jan 22 at 13:17
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    $\begingroup$ Since most mammals (including humans), birds and higher plants won't be able to live on the plateau, the climate is of little importance... $\endgroup$ – AlexP Jan 22 at 13:55
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    $\begingroup$ I see through the edit history that this question has been fairly broad at times and had other questions combined with it. The current edit looks pretty good though and I think the question should be left open. $\endgroup$ – Cyn Jan 22 at 15:24
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10km is waaaaaaay too high. On your world-building dashboard you have taken one of the dials, thought about turning it up to 11, and instead turned it up to 48.

But it is an interesting experiment to think about: what are the physical effects here?

  • Too heavy for the crust/mantle to support: The Himalaya and tibetan plateau are the biggest features Earth can support. Their height is facilitated by continental collision that can push up the thickened crust against the HUGE desire to sink down into the mantle like an icecube bobbing in a glass of water. You need a fundamentally different kind of tectonics to support this kind of feature, meaning a planet that is either old or small, such that it has cooled off and has a thick elastic crust atop the viscous mantle (eg. Mars).
  • VERY COLD: The atmosphere is, on average, 6.5K colder per Km elevation. So you are 65 Kelvin colder than sea-level on that plateau.
  • Not even normal atmosphere: 10km is near a point we call the tropopause, meaning the atmosphere is so thin that its temperature is no longer kept in a normal thermal distribution by collisional dynamics, and is instead radiatively-dominated. That doesn't actually affect much if you're living in it -- just feels like cold, thin air -- but I want to highlight HOW thin and cold that air is.
  • Messes up global winds: 10km wall? I can't even picture what than plateau does to airflow. Blocking global air circulation with an insane Rossby wave on the leeward wide? huge hurricane force gusts as air descends off the edge of the plateau? Some continual push of air to the outer edge of the plateau? Very disruptive to the global system.
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    $\begingroup$ do you have any evidence to backup your claim 'The Himalaya and tibetan plateau are the biggest features Earth can support'? $\endgroup$ – BKlassen Jan 22 at 17:35
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    $\begingroup$ Lots of bits of geology (look at rocks) and geophysics (maths on the probable behaviour of tectonics). GeoPhys: The speed of the collision between India and Asia was achieved by a dual trench system, which is unusual and therefore about the fastest a continental collision will ever get. We also see a lot of compensation mechanisms in how East china deforms instead of further elevation in the main plateau that suggests the you will struggle to gain further elevation. Not my exact field, but I saw some of the latest work in the 2012-16 period. $\endgroup$ – Mark_Anderson Jan 22 at 18:26
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    $\begingroup$ Geology: Mountain roots are a unique pressure-temperature scenario that produces unique metamorphosis of rocks. The extremis in P-T space is recorded in the minerals and rocks left behind. We can find these rocks in uplifted Himalayan material (see: mountain duplexes) and elsewhere as the remnant of ancient mountain ranges. These rocks back up the idea that the Himalayas are as tall things get to within meaningful error :). +1 for a good question. $\endgroup$ – Mark_Anderson Jan 22 at 18:32
  • $\begingroup$ very cool, thanks for providing reasoning, may want to consider adding this to your answer in case the comments ever get removed since its good information $\endgroup$ – BKlassen Jan 22 at 19:30
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According to this source, the climate up there would be extremly harsh, at temperatures around -35°C with strong winds. Because of the thin air in these heights, those may won't feel as strong as at ground level. Nothing would be able to survive in such heights, as this is even worse than the arctic climate.

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  • $\begingroup$ "Nothing would be able to survive in such heights, as this is even worse than the arctic climate." Living being survives in arsher environment than the arctic climate (namely the void of space, with more extreme temperature), so you might want to rephrase that part of your answer. No complex lifeform as we know it would survive. $\endgroup$ – Nyakouai Jan 24 at 15:29
  • $\begingroup$ I don't really get your point... but feel free to suggest an edit, I'll probably accept it. $\endgroup$ – miep Jan 24 at 21:01

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