How Do Caves Form?

hidden deep within the Vietnamese jungle province of kyeong bin lies a secret wonder of the world that is until 1991 when a local logger named Ho Khan made a spectacular discovery while searching for agarwood alone in the forest he became lost but soon stumbled upon a massive rift in the limestone mountainside out from the opening came billowing clouds the roar of rushing water could be heard and a strong constant gust of wind blew out from between the rocks for fear of the unknown ho Kahn explored no deeper than the entrance to this cave 15 years go by until in 2006 o Khan speaks with two members of the British Cave Research Association Howard and Deb Limbert who travelled to Vietnam to discover new caves intrigued by ho Kahn's description they seek him out and urge him to lead them to it but after many failed attempts Ho Khan could not rediscover what he had found by mistake all those years ago it's not until 2009 that by pure chance Oh Kahn finds himself back at the entrance of this cave wall on another hunt for wood this time he means sure to remember its exact location and contacted the Limbert immediately they returned to Vietnam as fast as possible and together with Ho Kahn and a team of other explorers they take man's first steps into the massive cavern in the mountains its uncovered that the cave runs nine kilometers deep into the earth with some parts reaching 200 meters high and 150 meters wide large enough to fly a Boeing 747 inside these dimensions make ho Kahn's discovery the largest cave on earth by volume coming in at over twice the size of the next two largest cave in total there's around thirty eight point five million cubic meters of empty space within this cave that's nearly the same amount of space as the Grand Canyon all hollowed out beneath the animate Mountains but this isn't the Grand Canyon this is hyung song Dule translating very roughly into English the name comes out as cave of the Mountain River this name comes from the fact that a stream of water pours out from the entrance of the cave a river seemingly coming from within the mountain itself miles deep into the cave jungles can be found inside it's to build lines which are basically breaks in the roof of the cave caused by sinkholes allowing sunlight to shine deep inside the earth exploring deeper inside this cave you can find stalagmites that measure up to 80 meters tall some of the tallest ever discovered even deeper and you can discover large cave pearls some the size of baseballs an occurrence so rare that you probably didn't even know cave pearls were a thing knowing all this I think it's safe to say hyung Seung Jun is not only a spectacular cave but also one of the most impressive sights on the planet but how exactly do caves like this form in the first place well to understand this process we actually need to start in the ocean you see sea creatures like crabs and corals as well as tons of microscopic organisms use the minerals dissolved in the ocean water to build their shells when they died their shells are left empty and fall to the ocean floor once this happens a few trillion more times the shells will begin to build up into a layer over time this layer of shells gets buried and buried and buried until it's under so much pressure that it becomes a single solid rock we call this rock limestone you've probably heard about it before and you've definitely seen it it's a grayish white rock found in many cliffs and mountains then depending on plate tectonics this limestone might get pushed above the sea and that's how we get limestone on dry land and in mountains if you're curious this is what limestone looks like under a microscope you can still see some of the skeletons of long dead sea creatures cool right okay so next we need to know what limestone is just a few seconds ago I explained that sea creatures take minerals from the oceans to build their shells and the primary material they do this with is called calcium carbonate this is a really good building material because it's strong and it's readily available in the ocean and can dissolve easily in ocean water so the materials get recycled and used by new organisms that's important remember that limestone dissolves easily even in weak acids lastly we need to know how the rain interacts with the atmosphere and the soil trust me this will all make sense in just a second so we all know how rain is made but for anyone who missed that day in school water from the ocean evaporates and maybe some water from trees of a bow transfer rates then this water collects and floats into areas of low pressures and low temperatures and condenses to become clouds if this moist air becomes too saturated with water some of it will precipitate out and fall to the earth that's what rain is but before that happens while still in the clouds the water molecules interact with the gases in the atmosphere some of the water will come in contact with carbon oxide and sometimes when they crash together they create carbonic acid a weak acid but still an asset then when this slightly acidic rain falls to the earth and travels through the soil it can pick up even more acids on the way down eventually this acidic water sinks to the water table and becomes part of the groundwater if this happens where there's a layer of limestone in the soil a slightly acidic groundwater can eat away and dissolve it until a cavity in the earth is created because again limestone dissolves easily even in weak acids this process can actually be remarkably fast in geologic terms hongseong doomed for example is only roughly three million years old that's younger than the famous Australopithecus fossil and human ancestor Lucy which is 3.2 million years old then Fisher's imperfections and sinkholes can create entrances to these hollow tubes beneath the ground and when they do you have a cave if the limestone is on the surface it can instead be carved into cliffs and other strange and unique shapes this type of landscape is called karst topography and the more rainfall and area gets the more karst topography can form and the greater number of caves and sinkholes there will likely be that's why Howard and Deb Lambert were in rainy vietnam looking for caves in the first place and that's also why it's no surprise that hongseong doom is where it is one of the wettest regions in the world now here's a rough map of where karst topography is to be found on earth you can see one of the biggest regions of karst topography is here in southeastern Asia right where Han Zhang Jun is to be found in this area you'll also find other strange karst formations like these famous mountains in China then over here in the United States is perhaps the second biggest patch of karst features and it's in this area that you'll find more famous caves like Mammoth Cave and Kentucky which is the longest cave on earth at over 650 kilometres long but let's go back to how caves form depending on the size and shape of the limestone layer a few different types of caves can be created but almost always a cave will have an entrance point where water can seep and called wallet and to point where the water empties out a spring in the case of Hong Hong doom the spring is actually what we'd consider as the entrance and thus wallets would be the two holes in the cave ceiling caused by sinkholes and that's essentially it there are two things I should know before ending however first while limestone is the most common Rock type for capes to Foreman any rock that dissolves in weak acids will form caves over time so deposits of rocks like dolomite gypsum and even marble can become caves given enough time but limestone is by far the most common second this is how solution caves are made and there are actually a few more types of cave in each one forms in a different way but solution caves are the most regularly occurring cave type so I figured that would be the focus of this video if you want to see another video on how any of the more rare cave types form maybe give this video a like and subscribe oh and I have a twitter now so if anyone is interested in getting updates when videos come out and such here's how to find me I'm not really used for the whole Twitter thing yet but you'll be able to find me on there from now on anyway I'll be back next week with another video thanks [Music]

Channel: Atlas Pro

Views: 479,920

Rating: 4.9692054 out of 5

Keywords: education, geography, science, cave, kave, caves, hang son doong, son doong, vietnam, viet nam, giant cave, biggest cave, largest cave, karst, karst topography, spelunking, geology, limestone, deer cave, asia, southeast asia, how caves form, how do caves form, what makes a cave, chemistry, mammoth cave, kentucky

Id: EX0q5I3-HZI

Length: 7min 21sec (441 seconds)

Published: Fri Aug 10 2018

Reddit Comments

[u/Cal1gula]

Really solid video. Hope you get some traction. Cross post it around for sure. Nice, succinct and easy to understand and interesting.

[u/johnlockefromhistory]

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