Geology of Minecraft: Caves!

Hello and welcome back in this episode we’re going to talk about caves and uh I’m gonna try something new at the end of the video I have some real life cave examples some uh stalagmites and stalactites and stuff that uh I’m gonna share with you so after punching trees

Exploring caves is probably the most fundamental part of playing Minecraft uh Cave generation was entirely overhauled in 1.18 and while this cave here was generated with the old generation uh we can go out a bit and check out the quote unquote new cave formations uh and uh and their biomes

So first up is a lush cave I really love this biome it’s great finding one of these when you’re caving it’s just like this little Oasis normally not many mobs spawn here because it’s all lit up but um didn’t really have much of an analog to real life caves well Mel’s

Caves have life in there normally they’re like eyeless fish and things like that that need to be in the dark uh the only areas where you’d find plants would be you know near the surface maybe at an opening or something like that because they need light to grow some

Caves that are open to the public have electricity in them and you can find you know some Moss or something like that growing in them so the Lush caves also have these stepped clay pools here and this reminds me of one of two things in real life

So first off if a cave has standing water in it like it has pools you can have the growth of minerals like right along the edge and that causes these little uh stepped kind of uh they’re called uh shelf Stones where they they kind of just form where the water is at

And as the water level changes then it can keep growing at these different levels but it more reminds me of stepped travertine that can form at a thermal pool like at a place like Yellowstone like trap travertine is a carbonate Rock uh like Limestone it’s normally associated with volcanic activity where

The groundwater is heated by a magma chamber and it dissolves some minerals on its way up to the surface and then when it cools down the minerals can precipitate from the water and you can form Ledges like this and I like that interpretation because this area would be like nice and warm

And heated from like the thermal Waters coming out okay we can return back and check the next one out drip Stone caves so sort of On The Other Extreme we have a drip Stone caves they feel dark and oppressive and convey a good sense of

Like what it feels like to be in a real life cave this biome contains large Columns of drip Stone as well as various sizes of pointed drip Stone you can also find larger Blobs of copper in these biomes and I’m I’m not really sure why uh I can’t really think of

Anything in real life to justify this and oars are a whole other video topic that I’m going to cover at some other time we will talk about the formation of caves like this a little bit later in the video but for now I’m just going to talk about the mechanics of the planet

Drip Stone and drip stone blocks that were added so the pointed drip stone blocks represent K formations primarily the stalactites and Stalag mites the uh classic waiter remember this is that the Stalag tights hold tight to the ceiling and the stalagmites might grow up uh to reach the stalactite with enough time

And uh below here the actual block the drip stone block this could represent some type of flowstone normally when water is coming down over a material like if it’s not dripping from something and it’s flowing over the side or Edge then it can just coat a rock and then

You get you know what we have called a flowstone there are tons of names for different types of cave formations but the general term for all of this is speleothem and I’ll be using that for the rest of the video so in Minecraft if a water source

Is above a point of drip stone block like this it’s a chance that the pointed drip Stone will grow down and that there’s the stalagmite below it can grow up possibly you know joining in the middle that in real life what is happening is that the water rain water is seeping

Down through the Rock and dissolving some minerals when that water comes into a cave it can evaporate and leave the minerals behind this is a very slow process in Minecraft the average growth rate is uh it takes about five game days for this block to grow once which is

About 73 meters a game year a Minecraft year and uh which blows away actual real life uh speleothem formation where the fastest a speleothem has been measured growing is 40 millimeters a year so you can also use the drip Stone to generate new water and lava sources by letting them drip into cauldrons

Um you know the water thing is a little bit realistic and the lava really you know is not lava would cool down if it was touching this stuff and you would form like little even if it could like get through and drip like this you’d form like little droplets of

You know obsidian or possibly Basalt or something like that also there’s the fact that we’re technically creating new matter uh in this process so uh we’ll just ignore ignore that uh violation of physics so the last use is for the conversion of mud to Clay uh great additions let me

Great additions to the game and it has a little bit of truth behind it the formation of clay uh cannons involve like the leaching of some minerals from soil like I mentioned in the uh the dirt episode but since we create mud from dirt in the game it would also have

Organic material and other um larger things like bits of quartz and stuff and you wouldn’t simply drain that out by you know just trying to draw water out of it you just have dry mud but still cool a little bit of Truth you know like other most things in Minecraft

But I think overall good addition okay and so we have one more biome to check out And that is the deep dark I don’t have too much to say about this biome geologically I just wanted to include it include it for completion’s sake um obviously it’s just a made-up biome and I really can’t think of what the skulk represents it’s kind of like a

Mycelium sort of thing mushroom but um I think it has more there’s more to come for this and the the ancient cities so you know there’s lore implications for this and but that’s a different video so we’re done with the biomes but there is one more thing to talk about

There is another type of feature that was added in 1.18 and and those are noise columns they can be they’re biome independent so any large room cave can have these columns and they vary from thin to thick let me turn the lights on so thin columns like single block or you

Have these thicker columns that are here behind me they’re made to look like joined stalagmites I think that’s the points leg mites stalactites but they aren’t placed after the room is generated they’re just left during uh World Generation so they still have all the rock types that would have been

There if the room was solid so obviously this is there’s some issues with this you end up having oars you can even have dirt in some of these columns and it would have been really nice if they would have came in here afterwards after a generation and maybe just replace

These entirely with like one rock type so either rock or deep slate but there’s issues with having caves in deep slate period like geologically accurate so and I’m going to talk about that a little bit later but uh I do think these are a good addition I I think the caves are

Better to have them even the way they are even though it’s uh you know it’s not accurate head back so now that we’ve looked at the caves from the inside I thought it would be interesting to look at the caves from the outside this is the same area that I used in the

Igneous rocks video but I added some commands that will let us fill in the caves and then we can remove everything else so I’m going to run a command here and then wait for it to finish okay it’s complete so I’m going to remove the igneous rocks and the oars

And then we can start taking away everything else okay so I think I have everything removed we can start removing the trees and the grass and if you’re doing this at home this can be a bit finicky it depends a lot on the machine you’re using and I don’t

Know I’ve had some problems with it but uh I’m trying to keep everything able to be done in vanilla Minecraft in this world so uh so your experiences May uh may vary okay so now I’m going to remove all the dirt down below and then we can start removing the stone actually I’m

Going to grab the map put in my off hand all right so now we start removing the stone and we can start revealing the caves so moyang has three different names for the cave types that they that they added and those are spaghetti noodle and cheese

I don’t know why they used Noodle and spaghetti those are both I mean spaghetti is a type of noodle I would have picked two different noodle names Maybe let me remove the Deep slate as well let’s see deep slate go all right so you can kind of see the

Shape revealed on the mat they kind of wind around they kind of loop all over the place they go you know up and down through elevation they can all connect to each other so they can all intersect in different spots we have the I think this is a spaghetti

Cave here it’s rather thin and then over here we have a noodle cave it’s a bit thicker sometimes they’ll just stop all together they’ll uh just dead end there’s one down here yeah there’s a one here you can see that doesn’t go all the way down it just

Stops and over here we can see one of the keys caves so like swiss cheese like the big holes that are in it these can be really varied in size the ones that are in this area are on the smaller size from what uh from what I’ve seen but all

Right I’m gonna reset the area and we can continue on our cave Journey so a word of caution if you are using the World download which is being provided for this one the reset over here is particularly finicky I’m using a structure Block in a way that it really shouldn’t be used

And it might crash the game um I’ve used it on a couple different machines sometimes it works just fine sometimes it’ll crash out and only reset like half the area and then you have to like hit the button again and then maybe it’ll crash and fill more and you might

Have to do that a couple times but I’m gonna try it and see I recommend hitting the button and then taking your hand off the mouse until you see trees over here or your game crashes so we’ll see what we get and it crashed okay so it crashed you can see part of

It loaded and part of it uh didn’t finish I’m going to run it again and let it sit I think the answer for this in the future is maybe I can divide this up and so it does like this like slowly kind of like how it reveals

Things that it it fills it back in it’s entirely dependent on how many blocks it’s replacing back to the original state so if I just remove you know the trees and then reset it it does it works like no problem but I’ll figure something out from the future all right let’s head back

All right as we go outside we do have one more cave-like feature uh in the game and that’s the Ravine you can find these at any levels they can be exposed on the surface or entirely buried in real life a ravine is just a narrow Valley cut by a river the Minecraft

Ravines tend to like narrow down on both ends and they remind me more of like a some sort of fracture that’s opened up and maybe lower wise this reveals something about the uh catastrophic history of uh Minecraft worlds so commonly in real life I think people think of three caves three types of

Caves and there’s plenty of other types of caves but I’ve made a little diorama for the The Big Three first up is a karst our solution cave these can have the speleothems uh in it these are normally dissolved out of rock and so this would area would have all

Been Stone you normally it’s Limestone possibly well I should say a carbonate Rock like Limestone or maybe an evaporite Rock which I haven’t talked about but that’s another topic and groundwater is coming through and dissolving The Rock and leaving a space so this is where my issue with the my technical issue with

The Deep slate caves is that slate as a rock is is much harder it has much harder durable minerals and it’s not dissolvable by a weak acid and so you don’t find caves you don’t find solution caves in a slate environment okay next we’ll talk about a glacial cave

This is where you have a glacier and you have some water melting and flowing down and then it’s on top of rock and then the water will flow along the rock normally melting more ice and you leave a space here and develop you know a cave sometimes these are called people refer

To these as Ice Caves technically that’s incorrect an ice cave is just a cave that is cold enough to form ice and the correct term is glacial cave we have one more to talk about and that’s a lava tube so when there is an eruption and lava is

Flowing on the surface if there’s enough of it and the conditions are right the outside of that lava flow can cool down and Harden while the interior is still flowing and so that outer shell also helps to insulate the interior and the rest of the lava can flow out and you leave this

Uh like open area in here I’ve uh I’ve been in a couple Lava Tubes um trying to remember there’s one in uh outside of north of Flagstaff Arizona in the U.S that you that tourists can go into it’s a really neat experience uh kind of scary though so like I said

There are other types of caves um but these are the big three and karst are the most common by far in the world and they were present where I grew up as a kid I spent a lot of my childhood playing uh in the woods and in sinkholes

Uh which are another cave formation feature like after a cave matures to a certain point the roof can become weak enough that it collapses in and then you have what’s called a sinkhole forming where things can start falling down into the cave probably not the safest thing for me to

Be doing as a kid but it was fun so if we go over to this area we can learn a little bit more about how these karst caves form and this was one of the when I had the idea for doing this series this is one

Of the first things that I thought about would be cool to do so bounce up here all right so down below us we have a village and they have a well and there’s a stream we can take a slice out of this ground and Rise it up

And I’ve edited this so it’s more of a simplistic version of real life not a Minecraft uh slice the stone here represents Limestone and there’s a fracture represented by Cobblestone and I’ve added a layer of granite down at the bottom to act as our basement rock and every place on Earth has some

Igneous rock underneath this us at some depth sometimes it’s from the surface all the way down to the mantle other places there’s lots of other rocks before we we get to it but that’s another topic for another video which there’s been a lot of those this episode

So this might not be intuitive but uh Limestone can be saturated with water all rocks have spaces in them some more than others for example generally Sandstone has a lot Limestone has some Granite has very little at some depth the Rocks beneath you are saturated with

Water and we call that the water table I am going to use a stripped warped stems and prismarine to represent that here you can see that the well water is the same level as the groundwater and that’s true like at a steady state uh just looking at a slice

And there’s a whole discipline of hydrogeology that deals with all of this stuff groundwater and all the all of its interactions that I’m not going to get into here this is just a simplistic model about caves the groundwater here is an equilibrium with the Stream So if

The stream erodes down and the water level goes down then the water table also will will drop and equal out to the stream this is dependent on climate and a ton of other things and again we’re talking about geologic time so years decades centuries however long it

Takes but all right let’s get back to actually talking about caves as rain falls from the sky it can absorb CO2 from the atmosphere and it forms carbonic acid it’s a weak acid and then when that rain water soaks into the ground it can react with the Limestone

And this is dependent on a lot of things but under the right circumstances a cave can form and now if the water table drops and there’s still water making its way down into the cave the water could have some of those dissolved minerals in it it’s already going through some limestone

And there’s spaces in the cave that are dry you know it’s uh not under water and in those areas that water can start to dry out and we can have speleothems form this is not true for every cave there are plenty of caves that are entirely dry and have no uh speleothem formation

But this is just this is just one case and so as time advances you can have more and more of the cave dissolve and as the water level drops this can happen lower and lower in the system you can still have some uh dissolving underneath depending on how you have water flowing

Underground but oftentimes the dissolution happens near the top of the saturated area but in the end you can have multiple levels of cave formation happen sometimes the water level can go back up and then you can get flooded caves again we find that in some of the drip Stone

Caves in Minecraft have I’ve been you know re-flooded eventually um maybe the roof of a cave becomes too weak because too much of a too much of it has dissolved and you can have a sinkhole form and so the Cave the Cave roof collapses and everything falls down

Into the cave and then this stuff can be can be moved by water and you can have more events that cause uh more sinkholes and more collapses to form you can also dissolve all the way out into the side of a cliff or uh out to a stream and

Then you can have access to like the cave from either the the side or or the top and so I don’t have a fancy way of getting rid of this uh no animation it’s just gone uh but uh behind it back with these Hills here these actually remind me of a fully

Evolved karst topography so the the last stage of cave development is basically the entire cave system is collapsing and you’re left with the areas that where caves end up becoming valleys and the high spots were where the caves weren’t there’s some really great examples of this in China if you Google um

Karst topography uh you can find some really great pictures of it online all right so that’s everything I have built to uh show you if I forgot something or got something wrong or you have questions leave a comment and I’ll get back to you I’m providing a world

Download for for the whole geology world for the first time um think of it as a beta or maybe even an alpha because there are some things that are just left incomplete and I’m working on things you know here and there I’m not trimming the world size either

Yet so it’s about one gig download and when new episodes come out of the geology stuff I will probably end up deleting the old versions online I’ll try to update the links so that it’s always act the the most current version but it just takes up a lot of space on

My storage and so I will try to replace it but if you try to download this later at some other time and the link is broken look for a newer episode and that’s probably where the an active a real link will be at I hope you guys enjoyed it

And like I mentioned at the beginning I have some real life examples of spill your thumbs to show you and so if you don’t want to mix your game and real life any more than this video already has I’ll uh I’ll see you next time otherwise I’ll be right back

So I don’t really have a setup to record anything in real life yeah so this is just my phone and a temporary setup but here’s a few spelia thumbs that I wanted to share with you and first off I’ll say that all of these were collected for research they are not my personal

Samples they’re property of the University I work at and you really shouldn’t collect these because take a long time to uh to grow and they’re quite special just where they’re at first off pretty generic looking uh Stalag type stag tights are normally more pointed

If I focus it at the end here you can actually see where it started maybe as a soda straw formation and then it grew out mostly in this direction and then there’s like this white ring where maybe there was environmental change that changed in the water that caused this uh

This different color to grow and then the final like layer outside I don’t know where most of these came from this one specifically is labeled uh okay it was collected in 1987 from a Cenote so probably some place in the Yucatan Peninsula second is this interesting piece here it actually broke off and

It’s cutting a tube but if you can see the actual growth lines this is another Stalag type so it would have been growing down this way but you can see all the little growth layers as it was growing on and then you can see right here some event happened I actually

Broke it so you can see how these lines truncate against it so something broke off and then it started to grow again and it continued to grow and have you know this second life uh that it grew on until we uh collected it so for research purposes we would take a

Sample like this and we could sample uh points along here we can uh date this we can look at isotopic values across here and actually learn something about the environment that it grew up in I thought this sample was a pretty interesting looking it actually looks a

Lot like the drip stone blocks we have in Minecraft it’s a flowstone it’s very thin and you can still see a growth pattern in it so you can kind of see that it was started out over here and then it grew along like this path as it grew outwards

So here’s one of the most interesting ones or my opinion is the most interesting one I should say that all of these I wasn’t involved with the research for any of this and I so I don’t actually know where they were where they were even collected from in some of the cases but

Like in the video in the early like in the Minecraft video These normally grow like in a dry cave or there’s no water uh present it’s you know water dripping through the cave and not something that’s a cave that’s flooded but for this one it had grown in the inside here

You know it’s probably something like a normal stalactite but water level then so it’s growing from this end you know is growing down this way and then in a dry cave and then water level will came back up and then all of these calcite crystals

Here grew on the edge of the uh of the stalactite so kind of like um rock candy uh if you could grow that like you don’t want to stick in your kitchen it’s kind of like that where all these crystals grew and then some other point water level went back down and

Then you know we were able to come back and Sample it those are the samples I’m sharing this time I might do this more in other videos for other things but I hope you enjoyed the video and I’ll see you next time bye