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I'm gonna talk about a really, really cool lake, but first, some geology lessons.

On Earth, mountains and valleys tend to be formed by tectonic motions or volcanism, and then shaped by erosion (mostly water and wind erosion) back into their lowest possible forms. This is why the Appalachians are so much more rounded than other, spikier and younger mountain chains...

On Mars, there is some evidence of that process having taken place as well, but mostly only in the distant past. On Mars, there is a very weak atmosphere which can't really do much to erode away mountains or craters, and so they stay, but the tallest mountains, they tend to flatten out just to the force of gravity.

Take the Alba Mons and Olympus Mons for instance, Alba Mons is a much older volcano, and it has been stretched out by gravity, trying to deform the planet back into a sphere, but Olympus Mons is younger, and that process has only just begun for it.

The stresses of weight of Alba Mons on the surrounding lands has caused a series of striking tectonic features, huge rifts where tectonic pressure has deformed the land. Olympus Mons hasn't yet deformed to the same extent that Alba Mons has, but all of the mass of the Tharsis igneous provinces are being deformed in this way.

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The Himalayas and highlands of Asia, likewise, is a very high up region with a lot of mass causing some strain gravitationally, but more than that, on Earth, there's tectonic plates. Huge slabs of crust that tend to move together, one of these places is where Asia is tearing itself apart, this is a place that's home to the world's deepest freshwater lake, a lake so big that it's about the same size as all the Great Lakes combined...

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I'm talking of course, about the Baikal Rift Zone in Siberia. Lake Baikal is located where the Eurasian Plate and the Amur Plate have begun to diverge, and a massive, deep rift in the Earth has long since been filled by water.

Is Eurasia tearing itself apart because the continent is too heavy? Probably not, continents generally make up their height by being less dense than ocean crust, but even so they are still heavier than the surrounding regions. Perhaps this a factor in why plates move? Convection of heated rock in the mantle is also a huge factor, and so too is erosion and all those Earthly things, but gravitational deformation is also at play. And as we can see, on Mars it has had a big part in shaping the way that planet is well, shaped. But enough about tectonic stress, let's talk about this funky, tectonically created, deep lake.

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Lake Baikal is the world's oldest, deepest, and weirdest lake. It's DEEP. It's huge too, it stretches for nearly 400 miles (636 km).

Baikal is, by volume, roughly the same size as all of the Great Lakes combined.

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Baikal seals, or nerpa, are the world's only exclusively freshwater seal! They are a kind of Arctic seal and they are endangered.

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They've had a looong time to adapt to these conditions, too. The Great Lakes, which themselves are home to many species of animals which call them home, are only 20,000 years old.

Baikal is at least 25 million years old, by comparison. In its deepest depths it's got some actual hydrothermal vents because of the tectonic activity, and it is the only freshwater lake in the world to have these. Living in these vents are a variety of endemic species which live entirely without need for the light of the sun. Like the freaky depths of the ocean, but like, in a single lake. Weird looking sponges, mats of bacteria, and even some funky freshwater amphipods which are all endemic to Baikal all rely on these vents.

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These vents release methane and other gasses, which in frigid Siberian winters, the bubbles of methane will get trapped in the freezing ice around them, producing these beautiful, beautiful photos of what looks like thousands of spheres suspended in the ice.

Here's a gif of a guy breaking into one with a knife and catching it on fire with a match as all the methane burns up.

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Lake Baikal is truly unique. It's beautiful, ancient, and it's kind of unreal. If you didn't know about it before, now you do.

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@starwall does this absence of tectonic activity plus gravity almost on par with earth lend evidence to why there aren't many mountain ranges of note (that we know of) on Venus

@patience Venus does have tectonics, just not global tectonic plates like Earth does. Both Mars and Venus have some local tectonic stuff going on. Theories abound as to why Earth has tectonic activity such like it does, mostly it's chalked up to convection of the mantle.

@patience that definitely plays a factor in geology, for sure. erosion is far more efficient at spreading out a mountain chain than gravity alone ever could be... depending on the gravity of the planet that is.

@starwall owo *notices the moses-saunders dam in the map*

hey that's not too far from where i live

@starwall trying not to laugh at the shape of that cross-section ngl

@starwall I did not know, the name was vaguely familiar, but now I know more! thank you, that's really awesome! :D

@starwall Thakn you for this thread. Lake Baikal is amazing - I've actually seen it once from a train, passing by very slowly in spring when it was still frozen over. It feels incredibly big when seen from the shoreline.

@starwall I knew about it but, it turns out, it’s even cooler than I realised!

@starwall lake baikal is really great, I've only visited in summer once, but this was an amazing experience. Although due to temerature it's not that great for swimming :-)

@starwall
Is it true that soviets buried plenty of nuclear waste in it?
And that some nuclear test were also realised there or close by?

@rmdes @starwall Honestly, I have never heard of that. Probably somebody has mixed it up with a big paper factory, that did cause lots of harm. However, it was closed down in 2013.

@SeventhMagpie
I really want you both to be right but a simple Google search with "Nuclear Waste Baikal" is telling a completely different story sadly :/
@starwall

@rmdes @starwall I don't see a completely different story. Also it has nothing to do with the Soviet era. Basically, it's about the recent initiative to redact the law about what is prohibited in the area. Hence, it would enable building a waste processing facility not far from the lake for Angarsk Chemical Plant waste + waste remaining from the Pulp & Paper factory.

@rmdes @starwall Nothing has been built yet, no facility. Besides, even if it were built (I hope not), it's not supposed to dump anything in the lake.

People are concerned that something *might* happen at some point, a leak or something. And that hazardous substances might get into Bailkal.

Irkutsk and Buryatia authorities are concerned with this, too. At the moment nothing is being built. The recent discussion with Buryatia reps was in the middle of July.

@rmdes @starwall The biggest issue at the moment is waste that's left from that paper factory closed in 2013. It has not been processed yet, so the next flood might result in a catastrophe.

It's not radioactive, but it's no less dangerous.

@SeventhMagpie
I'm not speaking about last year or recent stuff. I'm speaking about the hundreds if not thousands of nuclear test Russia, USA, China, France did for over decades.

Some information points toward the notion that Baikal may have been polluted. Nuclear waste isn't normal waste, it doesn't disappear just like that. Every nuclear country messed up with dangerous tests for decades. Nuclear Tests were & still are an ecocide.
researchgate.net/publication/2
@starwall

@rmdes
Cannot argue about nuclear tests. These should definitely be stopped.

However, your link refers the work about pollution of soils in the great Baikal area (which is not just the lake itself, but a big area including two regions). They point at Semipalatinsk tests in 1953 and 1956, which resulted in some radioactive fallouts due to winds.

There is no plenty of nuclear waste buried *in* Baikal.

@starwall

@rmdes
The biggest threat as of now is waste left from the paper factory, like I've already said.

Authorities cite lack of technology, lack of agreement, other reasons. But the longer it is stuck there, the greater is the risk that something might happen and it will get washed directly into the lake. And it's chemicals, so it's not much better than radioactive waste.

This is much more dangerous than soils polluted by fallouts 70 years ago.

@starwall

@SeventhMagpie
I agree this is an immediate danger, I hope it will be well managed.
@starwall

@rmdes
I hope so, too. It's really important that discussions about this situation continue, and that local reps and activists keep pushing.

However, I'd prefer for authorities to stop talking and start doing something already, you know.

@starwall

@rmdes No, it's actually pretty well known to be one of the cleanest lakes in the world. The Soviets did dump plenty of nuclear waste into a different, smaller lake though, Lake Karachay.

@starwall I knew Lake Baikal since I developed an interest of reading and maps (i.e. since I was 5 years old). But that tidbit did always elude me.

@starwall Thanks for this thread. I remembered reading about it many years ago. Absolutely beautiful place.

@starwall not true! The other species is the endangered Saimaa ringed seal!

@piebald This is mostly true, but Saimaa aren't exclusively freshwater, or at least they didn't used to be until getting so endangered. Nerpa are the only "true" freshwater seals

@starwall afaik they both diverged to be exclusively freshwater seals around the last ice age, which yes is "fairly recent"

@starwall oh fuck yes this thread owns
I read an issue of National Geographic all abt lake baikal as a kid and it’s always fascinated me

@starwall Still blown away by how DEEP Baikal is. I honestly had no idea it was this extreme!

@starwall gotta love how baikal is cropped out of the preview in that diagram just to maximize the holy shit moment

@starwall this is aweseome. when i see picks like this, i think i have to go down there and see if there is a hole to the center of the earth, or something, but i know it would scare the tar out of me because there are sure to be monsters down there lol

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