Realism of Mordoresque land

[Peregrine]

When I say Mordoresque I mean Mordor, Fire and Brimstone Hell, Muspellheim, Shadow Lands and so on.

In my medieval-themed non-Earth setting, an epic meteor hit the planet 50 millions years ago.

Could a meteor strike into a planet so deep that it leaves a crater that exposes the liquid magma to the surface of the planet? There is another thing to add, the radius of the meteor hit several volcanoes that existed before the meteor impact. This crater is of colossal proportions. It is the size of Switzerland.
Like in deserts, plants cannot grow in this crater because its too hot.

I am imagining this crater to have black soil, lakes of magma and some volcanoes.

The liquid magma is always exposed to the surface, but I wonder will the magma that comes in contact with the planet's surface be cooled after 50 million years like lava and turn into solid state, or will the magma lakes in that crater always be
lakes of forever-burning lava since the meteor made a crater so deep into the planet's "yolk".

 

[TheKillerBs]

Yes, but that would be a catastrophic event that would lead to mass extinction. You're talking about a crater that would be over ten times larger than the one in Yucatan, which is believed to be the one that gave the non-avian dinosaurs the deathblow.

 

[Peregrine]

Yes, but that would be a catastrophic event that would lead to mass extinction. You're talking about a crater that would be over ten times larger than the one in Yucatan, which is believed to be the one that gave the non-avian dinosaurs the deathblow.

I decreased it down to the size of Switzerland.

What if it happened millions years ago, in a "dinosaur age"?

 

[CupofJoe]

What if it happened millions years ago, in a "dinosaur age"?

Then you would have millions of years of recovery and evolution. There are a few lava lakes on Earth. They are tiny, a few hundred meters across but I think it should be possible to create a world where they were more common.
The "trouble" with impacts is that they tend to go from minor nuisance to planet killer fairly quickly depending on size, speed, composition, angle of impact, place of impact, time of year etc. And your readers will probably nit-pick any figures your give. You might want to look at something like The Deccan Traps. A series of huge volcanic events that probably did as much if not more to change the post-dinosaur world than the asteroid...

 

[TheKillerBs]

In all honesty, my advice would be to ditch the asteroid impact idea and go straight to the tectonic movements. I don’t know if I’ve said this before on one of the Mordor complaint threads but Mordor is plenty realistic already and if you have any problems with it you should also take it up with Asia.

 

[DragonOfTheAerie]

After millions of years, that crater would close.

That said, an impact that devastating would not just be a mass extinction, it would pretty much wipe out all life on the planet, I would think. Earth's crust is many miles thick. I have no idea how big an object would have to be to blast through the crust but it'd be an unimaginably devastating impact.

Probably go instead with a planet with more tectonic activity than Earth, and just have a constantly active volcanic region.

Edit: Upon some screwing around on Wikipedia, the meteor that ended the dinosaur age dug a hole into the crust 19 miles deep. On land that doesn't quite penetrate clean through the crust. Oceanic crust is a lot thinner but I'm not sure how an impact with the ocean would work differently.

About a crater the size of Switzerland, uhh...Switzerland is bigger than the Yucatán crater, but not by too much. and your object would have to be bigger (maybe? there are other factors) so that fits.

Idk whether it would wipe out ALL life, like i said earlier (there'd still be simple organisms at least) but it'd probably cause more problems than the object that killed the dinosaurs.

It still wouldn't remain consistently open, though, which kinda makes all my wikipedia-ing irrelevant.