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What would cause/allow a planet with very high gravity to have tall, sharp mountains?

Mountain height is generally capped off by gravity, erosion, and the mountains composition. On a higher gravity world, mountains likely wouldn't be able to get very tall or jagged, but I love the idea of a planet having harsh, steep terrain AND gravity high enough to make travel even more hellish for nonnative explorers.

Ideally, I'd have the gravity be 1.5-3 times that of earth.

For visual appeal, I'd also prefer the rocks making up the mountains and crust to be primarily black or dark grey in color.

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    $\begingroup$ The color of the rocks is entirely up to you. It's basically a narrative choice. Note humans are unlikely to survive long in high gravity. Our bodies (and most animals on Earth) need around 1g to function properly in the long run. We manage sustained periods of lower gravity better (but it's still not healthy in the long run), but sustained high gravity is a major no-no. $\endgroup$ – StephenG Mar 17 at 21:57
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Make the plate tectonics that throw up the mountains super aggressive.

[mount fitz roy[1]

https://en.wikipedia.org/wiki/Fitz_Roy#/media/File:Fitz_Roy_Chalten_Argentina_Todor_Bozhinov_2013.jpg

The process that lifts mountains on earth can lift some crazy jagged mountains. Gravity has got nothing on plate movements. Sure gravity is going to whittle them away via "mass wastage". Have them come up faster than that.

Your planet has super active plates. That also means probable frequent earthquakes and possible rapid motion upward from time to time. There is nothing better for a party of adventurers clambering over jagged mountains than to get shook up by an earthquake. Which would also loosen any snow that might have accumulated up there...

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    $\begingroup$ Keeping in mind that, geologically speaking, such tall mountains just won't last. $\endgroup$ – WhatRoughBeast Mar 18 at 3:36
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    $\begingroup$ A more agressiveness tectonic movement means more speed. In a high gravity environment the same forces will create sharped features will colapse them. Plus the weight of those features will make it drow into mantle, as well the subducted plate will drow faster too. $\endgroup$ – Rodolfo Penteado Mar 18 at 3:47
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    $\begingroup$ @WhatRoughBeast - yes. As on earth, sharp jagged mountains are young mountains. $\endgroup$ – Willk Mar 18 at 13:30
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    $\begingroup$ @WhatRoughBeast: Each individual one won’t last, but new ones are being created more frequently, so the overall situation of “plenty of jagged mountains” can last just fine. $\endgroup$ – Peter LeFanu Lumsdaine Mar 18 at 13:43
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A low density of mountain composition i.e. in the planet crust.

Maybe this planet hasn't got a asteroid bombardment during their formation and high dense materials compose the core, and light ones are in the surface.

Could be a cold planet, with ice and other volatile compounds mixed well in the rocks. The rotation of planet is also kinda slow and the cold atmosphere has weak winds, thus a weak aeolian erosion.

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  • $\begingroup$ Wind erosion is weak in comparison with erosion caused by glaciers' movement. A slow rotation will ensure the sublimation of volatiles and, depending on how long the day is, piling them high on the dark/colder side; if this happens, they will need to come down eventually. $\endgroup$ – Adrian Colomitchi Mar 18 at 1:09
  • $\begingroup$ @AdrianColomitchi depends of distance of planet to the star. That i meant with 'kinda slow' is something a bit more than Earth like too, not a Venus like one. $\endgroup$ – Rodolfo Penteado Mar 18 at 3:40

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