Detour To Vatnshellir Cave
August 1, 2019 Filed under Curious
“Welcome to the Vatnshellir caves! We will be your guides into this amazing place.”
These caves were formed by an eruption from a volcano that is now known as Purkholar crater. The volcano is a stratovolcano, which means it is an especially explosive type of volcano, and it is said to erupt once every 2000 years, and the last eruption was 1800 years ago. So, you can bet we are all keeping watch!”
“Make sure you have your flashlights and helmets, and keep your pockets closed because if you drop something down there it will be very hard to find. You can take plenty of pictures but you can’t take any souvenirs please.”
“The way these caves were formed is, there was an eruption and lava flowed down a bunch of riverbeds and valleys, making lava rivers. The top layer of the lava was exposed to the cold air and solidified, and made a thin crust over it, while underneath there was still molten lava flowing, trapped under the top layer. When the eruption stopped, the rest of the hot lava gradually drained out. You will see some evidence of this in the cave.”
“Okay, let’s divide into two groups. When my group is inside, I’ll ask the last person to close the door behind them. You’ll have to slam it pretty hard. Then lock it, because we don’t want random people sneaking in after us and hiding inside!”
“Get one or two steps away from the bottom of the stairs, and the cave opens out. Take a look around with those flashlights!”
“The area we’re standing in is pretty big, because a lake of lava accumulated here before it moved on. But to get in here you’ll notice we had to walk uphill. So, where did the lava come from? Well, look at the stalagmites.”
“The ones along the walls over there are no longer growing, and they’re actually close to 8000 years old. They were formed when the walls of the cave were really hot, just after the lava left. But on this one section of wall, the stalagmites are relatively new, and growing. They are being formed by dripping water.”
“So the lava flowed through and emptied out, and these first stalagmites formed, and then the water dripping through the cave slowly made these other stalagmites grow and eventually they sealed up the part of the tunnel where the lava came from. There’s probably a bunch more caves beyond this wall, and one day we might explore them.”
“Unlike caves in other parts of the world, there are no animals in here. There are no bats in Iceland, or lizards or snakes, and no birds nest in here. There isn’t even anything for insects to eat. But there is bacteria. And some of the different colors you see on the walls here are from different kinds of bacteria. Don’t worry, none of them are harmful.”
“So, we tourguides call these two formations Homer and Marge, because they look a little bit like the cartoon characters. How long do you think it took for them to grow here? Any guesses?”
“Those are some good guesses, based on the age of the caves, but the formation of both Homer and Marge was actually something closer to 48 hours. There are different processes happening at different rates in the cave, and some are very fast.”
“So, one of the reasons we call this formation The Thumb is because it could be part of a giant hand. See the other formations just there, a bit like fingers? And if there’s a giant hand, it must be attached to a giant body. So we like to pretend there is a big troll here, trapped in the rock. Look further up the wall there. Doesn’t that big boulder look a little like a troll head?”
“Now, this big boulder fell down from the ceiling about 8000 years ago, when the cave was cooling off. It weighs about 30 tons. That same cooling made the cracks all along the ceiling that you see here. So, it might look like the whole thing is ready to come down any minute, but fortunately that’s not so.”
“Alright, now come along with me and we’re going down this next set of stairs, into the deepest part…”
“Okay, now, we’re going to try an experiment. I need everyone in the group to turn off all their electronic devices that make light. Even the ones with just a little red indicator on them or something. Then I want you all to turn off your flashlights. We’re going to turn off all the lights in here and we’re going to wait a while, and we’ll see if your eyes can adjust to the ambient light.”
“Is everything turned off? Alright, I’m going to turn off my flashlight now. But first, close your eyes, and keep them closed until I say to open them. It will be about a minute, so the eyes have plenty of time to adjust. Ready? Here we go.”
“Okay, open your eyes! Hah, there’s absolutely no change huh! Hold up your hand, directly in front of your face! You can’t see it at all, can you! That’s because it is absolutely, 100 percent pitch dark in here. There is zero light. None. This is what it’s like in these caves, all the time, when we aren’t here. Pretty amazing huh? While it’s dark let’s also listen to the sounds of the caves. They make a music all their own.”
“… Okay, let’s turn on our lights again. Get ready. You might want to close your eyes again so it’s not a big shock.”
“And that completes the tour! Now let’s make our way up to the surface! Make sure to post all about it on your Facebook and your Instagram and things, so more people learn about us. Sorry there’s no wifi down in the caves.”