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One of the cities in my world, known as Kerkapeze, is situated in a location I just realized I'd have to be very creative to justify: it lies on a narrow plateau between two high but very small mountain ranges nowhere near a plate boundary. Here's some screenshots of the city (which I spent waaaay too much time making with Civ6 mods) for reference: Kerkapeze (South POV)

Kerkapeze (West POV)

Kerkapeze (East POV)

This is all located in the Argentolian desert, a vast, flat area forming a sort of neck sticking out of the east end of the Tauropean Plate with an elevation of generally around 1500-2000 feet above sea level. However, I needed these mountains here to force the two rivers to diverge at the proper point for the city to be built in the hourglass-shaped area between them. However, the mountain ranges aren't all that big, because I needed the rivers to eventually converge further downstream. Here's a Koppen Climate map of the Argentolian Desert so you can kind of see how big these two mountain ranges are compared to both the city and the entire desert region:

Argentolian Desert (Koppen)

I do not have a tectonic map made of the region, so you'll just have to take my word for it here. The desert is bounded by convergent plate boundaries in the north and south, where you can kind of see the edges of bigger mountain ranges if you look closely at the koppen map. The issue here is that the mountains near Kerkapeze are nowhere near these plate boundaries and rise suddenly out of a very flat area, so I would need to find a way to justify the existence of these mountains. If it's even possible to begin with, how could high, small, isolated mountain ranges form in areas with no nearby plate boundaries?

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    $\begingroup$ Mountain ranges are create sometimes on top of plate boundaries, but also quite often at some distance from them. For example, the Pyrenees, the Alps, the Carpathians and the Caucasus would qualify as high mountain ranges created by tectonic activity, but they are quite far from the plate boundaries which pushed them up. For example, consider the Tatras, the most spectacular part of the Carpathians: where is the closest plate boundary? $\endgroup$
    – AlexP
    Mar 24 at 13:33
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    $\begingroup$ Those mountains could easily be tectonic in origin, mountains created by plate boundaries can be fairly far away, look at he Rockies or Altai. but the region looks fairly small, like smaller than Rhode island. so you could be close to the plate boundary. Any map you can see a city on is small scale. I suggest adding a bit of scale if it is bigger. $\endgroup$
    – John
    Mar 24 at 15:04
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    $\begingroup$ +1 For the Civ 6 screenshots $\endgroup$ Mar 24 at 20:46
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    $\begingroup$ Look at the geology of the Chinos Mountains in the Big Bend area of Texas. An isolated 7000’ mountain range in the middle of a large flat plain. $\endgroup$ Mar 25 at 5:17
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    $\begingroup$ @BruceWayne the Koppen map was made in Photoshop and the city maps were made in a HEAVILY modded run of Civilization VI $\endgroup$ Mar 25 at 16:52
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If it's even possible to begin with, how could high, small, isolated mountain ranges form in areas with no nearby plate boundaries?

You asked for no nearby plate boundaries. This means that there should be no plate boundaries now, or today. But, what about plate boundaries in the very distant geological past?


Your very red map looks remarkably like the Ural mountain range: enter image description here

These mountains formed during continental collision that happened 300 to 250 million years ago.

It is very safe to say that there is no plate boundary at this present time.

The earth is scattered with remnants of previous plate boundaries, which do no exist any more. This is exactly what has happened in your Argentolian desert.


Let's look closer.

enter image description here

I marked two rivers that flow on each side of the range. They are actually part of the same river system. But it doesn't take much to separate them into two distinct rivers. Just increase the elevation a bit at that place in the middle, and the river stops flowing there. That's exactly where you put your city.

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    $\begingroup$ The Urals are many things, but "very high" they are certainly not. $\endgroup$
    – AlexP
    Mar 24 at 13:28
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    $\begingroup$ @AlexP a thousand metres might be a fraction of the Himalayas, but when put in a flat plateau, they would be "very high" to many people. And, if not high enough, go back 50 million or 100 million years. Then, they will be much higher, and still 200 million years away from when it was active, sitting comfortably within the "not plate boundary" zone. $\endgroup$
    – Gimelist
    Mar 24 at 13:33
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    $\begingroup$ Upvoted. Just observing that we have the Pyrenees and the Tatras etc. as present day examples of high mountain ranges created by tectonic activity which are quite some distance from the plate boundaries which pushed them up. $\endgroup$
    – AlexP
    Mar 24 at 13:38
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    $\begingroup$ This answer is correct, but it just gives examples rather than explaining the actual geology. I would just suggest adding some more details onto how this actually happens - the cratonic shields. Another good link - en.wikipedia.org/wiki/… $\endgroup$
    – Sachin
    Mar 25 at 9:13
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The high mountain range is the result of a violent impact on the opposite side of the planet. As a result of the shock wave propagation summing up with the ejecta from the impact landing on site, the other side of the planet gets this "bump" in a region which otherwise would not have any significant elevation.

An example of this is visible on Mercury

When Mariner 10 flew past Mercury, it caught an immense impact basin lying half in and half out of sunlight, which they named Caloris. Even with only half the basin visible, scientists knew it was one of the largest in the solar system. Geologists had to wait more than 25 years to see the rest of Caloris, and when they did it turned out to be even bigger than they had thought. But the fact that Caloris was only half in sunlight was fortuitous in one sense, because it meant that the spot on Mercury that was exactly opposite the area of the Caloris impact was also partially in sunlight. That spot looks weird. In fact, this area has been referred to since Mariner 10 as the "weird terrain" on Mercury. And MESSENGER's orbital path has finally taken it over the weird terrain to get a good view: The MESSENGER photo doesn't make it immediately obvious what is going on geologically, but it does confirm that this "antipodal" terrain looks different from other areas of Mercury. But why should terrain antipodal to Caloris look unusual? [...] the point on Mercury that's farthest from the Caloris impact actually gets magnified effects;

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    $\begingroup$ On earth it creates a volcanic hotspot. $\endgroup$
    – John
    Mar 24 at 14:44
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    $\begingroup$ "violent impact on the opposite side of the planet" - this kind of calamity would greatly exceed the size of Chicxulub event and likely turn an Earth-like planet uninhabitable for some time. $\endgroup$
    – Alexander
    Mar 24 at 17:10
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    $\begingroup$ @Alexander That might not matter, depending on how long "some time" was: if habitability returned before the bump was flattened, you'd have your anomalous terrain. $\endgroup$
    – IMSoP
    Mar 24 at 21:14
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    $\begingroup$ @IMSoP agreed, but this event would likely throw the planet back to Precambrian level. If humans are supposed to naturally evolve of this planet, its timeline would be questionable. $\endgroup$
    – Alexander
    Mar 24 at 22:12
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They are constructs.

mountains of madness https://www.deviantart.com/corwin-cross/art/Mountain-of-madness-432428687

At the Mountains of Madness H.P. Lovecraft

“Moulton’s plane forced down on plateau in foothills, but nobody hurt and perhaps can repair. Shall transfer essentials to other three for return or further moves if necessary, but no more heavy plane travel needed just now. Mountains surpass anything in imagination. Am going up scouting in Carroll’s plane, with all weight out. You can’t imagine anything like this. Highest peaks must go over 35,000 feet. Everest out of the running. Atwood to work out height with theodolite while Carroll and I go up. Probably wrong about cones, for formations look stratified. Possibly pre-Cambrian slate with other strata mixed in. Queer skyline effects—regular sections of cubes clinging to highest peaks. Whole thing marvellous in red-gold light of low sun. Like land of mystery in a dream or gateway to forbidden world of untrodden wonder. Wish you were here to study.”

Your preternaturally high mountain ranges are ancient constructs, pushed out of the ground by a prehuman race. They are much weathered in these latter days and were higher yet originally. People in your world may or may not be aware of the provenance of these mountains. Maybe someone should go explore them?

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    $\begingroup$ Oh, my, how can I just from a glimpse of the answer's title can tell that it's from @Willik :) $\endgroup$
    – Alexander
    Mar 24 at 17:28
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    $\begingroup$ I was thinking about the city. Of course it is built on top of the old abandoned prehuman city, which ancient humans found to have robust if somewhat eerie buildings. Those buildings are now largely covered over the millenia by the rising city. Deep excavations may turn up... interesting things. $\endgroup$
    – Willk
    Mar 24 at 21:13
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Here is a diagram of the Pacific tectonic plate on Earth:

Pacific plate map

If you look in the upper-middle area, you can juuust about see the islands of Hawai'i, a looong way from those plate boundaries.

Here's a second image, showing the depth of the Pacific:

Bathymetry of the Pacific

You can see there's a long streak of seamounts stretching all the way from Kamchatka to Hawai'i. This is caused by the Hawai'i hotspot, a plume of of rock in the mantle that causes volcanism at the surface even far from a plate boundary.

You can use this same mechanism. You can handwave the hotspot starting and ending, too... no-one is quite sure about their nature, so you've got a lot of wiggle room here. What you end up with is a streak of mostly extinct volcanic mountains, pontentially with live new eruptions at the end, if that's what you wanted.

You can certainly get quite large mountains this way... Mauna Kea sticks up 4000m above sea level, but more like 10000m from the ocean floor to its peak.

Hotspots under continental crust might well behave differently, but you should still be able to get what you want.

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    $\begingroup$ Hot spot tracks look very different to the mountain range that OP was showing in his diagram. They only look like the Hawaii-Emperor chain when underwater. When in the continents, they form magma of the type that blows up everything and doesn't really make mountains. The Yellowstone caldera and related volcanism is an excellent example. $\endgroup$
    – Gimelist
    Mar 24 at 12:29
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    $\begingroup$ The EAR, being a rift is, by definition, a plate boundary. $\endgroup$
    – Gimelist
    Mar 24 at 12:37
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    $\begingroup$ @Gimelist it is a plate boundary being formed. There's a plume underneath it, driving its formation. $\endgroup$ Mar 24 at 12:37
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    $\begingroup$ Well, plate boundaries don't form in an instant. It has been forming for many millions of years now. It is sufficiently old that in the north part of it there's actual oceanic crust (Red Sea) separating continental crust (African and Arabian plates). It is actually made up of lots of tiny plates with fuzzy boundaries between them. I think it's safe to say that it is a plate boundary, at the moment. In any case, the topography formed in a rift-style tectonic setting would differ to that of a hotspot track, and differ to what OP wants. $\endgroup$
    – Gimelist
    Mar 24 at 12:47
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    $\begingroup$ @Gimelist right, they don't form in an instant, implying that at some point there was a plume with geological changes above it before rifting occurred. $\endgroup$ Mar 24 at 13:17
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Another possibility is erosion. An area with two different types of rock and over time one is gone and the other remains, like Uluru in Australia.

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    $\begingroup$ The tepui are another good example of this sort of thing (and present wonderful opportunities for "lost worlds" on the top). $\endgroup$ Mar 24 at 12:30
  • $\begingroup$ Oh, I've wanted to go there for a while. Another example are Karsts. $\endgroup$
    – Allan
    Mar 24 at 12:33
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    $\begingroup$ expanding this with a more detailed description of what creates it would make this better. examples include Devil's tower, Mount Conner, ect. I want to upvote this but as is I don't think most laymen will understand. $\endgroup$
    – John
    Mar 24 at 14:56
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Paektu Mountain between North Korea and China is not situated at either a plate border nor volcanic hotspot like Hawaii.

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    $\begingroup$ This answer would be better if you could explain why the mountains do exist. I think that's what the OP is looking for. $\endgroup$ Mar 24 at 19:51
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    $\begingroup$ @JBH Your right, but what I saw about it it's some super complicated geology stuff, that I didn't really feel confident about explaining. But wanted to add the name, so he at least could look it up if it sounded interesting $\endgroup$ Mar 25 at 8:03
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I have no basis or example to share for this, but could a small mountain area be created by debris? That is, perhaps some form of extra-planetary objects that somehow land quite slowly (so they don't explode and cause a crater), and all land nearby to each other.

I have no idea if this is possible, but what if such an object were a large rock, which is on an elliptical orbit, on a different orbital plane to the planet. It forms like this, and only millions of years later the two objects find themselves intersecting each others orbits and colliding. Since they're both orbiting in the same direction around their star, their speed of impact is slow, and perhaps somehow the smaller of the two ends up "lumped" on top of the larger planet, perhaps breaks up a bit into smaller chunks and then erodes and settles in over the next couple of million years.

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    $\begingroup$ You are thinking of "contact binary" and I don't think it would occur for a planet. If anything, it would be shredded when it got inside the Roche limit. There's an old question discussing that. $\endgroup$
    – JDługosz
    Mar 24 at 22:02
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    $\begingroup$ The only way you'll get something to land slowly is if it's got parachutes or rocket engines. Anything unpowered is going to hit Earth's atmosphere at 11 km/s or faster. $\endgroup$
    – Mark
    Mar 25 at 20:18

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