Going underground: Walking Lava Tubes
A lava tube is a rather unique phenomenon experienced when flowing lava moves underneath the hardened surface of already cooled lava. When air gets trapped and the lava solidifies, what is left is long cave networks. It is like walking into a giant underground bubble. Leiðarendi is the name of the lava tube network we got to explore. It is considered a prime example of an Icelandic lava tube, with distinct layers of lava visible throughout, like rings in a tree.
We visited Leiðarendi on a cold November morning. Snow had recently fell, turning the lava fields a bright white, with snow-capped volcano peaks in the distance. After getting out the 4x4 we headed down a small untouched pathway to an open hole in the ground: the entrance. Including the guide there were just seven of us exploring the tubes. This small group certainly made the experience intimate and more special.
Once we had entered the tubes, the temperature changed instantly, the cold conditions of the snowy outside were no longer. Inside, the temperature was warmer and the further we explored, the more we forgot about the conditions outside. We wore helmets and head-torches throughout the exploration which was definitely required, as about 20 minutes in, the ceiling of the tube was much lower and we had to almost crawl through the network of tunnels.
The natural beauty of the caves was something we were in awe of. Stalactites hang from the ceiling, shimmering in the light from our torches. Delicate stalagmites are dotted around the floors everywhere you look. The sounds of the cave were something that struck me. The odd drip here and there but apart from that, the quietness felt as though we were the only people for miles. As it turned out, not only were we the only people for miles, we were the only living things (or so we were told).
Our guide was very knowledgeable and explained to us about the freeze thaw weathering that has occurred during the years in the tubes. This unearthed patterns that indicate various lava streams. The layers in the rock, showed us different types of lava as well as the lava flow. We walked on two different types of lava; Apalhraun and Helluhraun. Apalhraun is a spikey, loose, jagged rock that is caused by rapidly cooling lava being repeatedly torn by the fast flow underneath. This was the most common type in the caves. We came across Helluhraun later on in the tubes. The lava is much thicker and flows slowly, giving it time to harden as it flows. This leaves a smooth surface to walk on, just be careful you don’t slip like some of us did!
The picture above is of Apalhraun lava, note the sharp, jaggedness of the floor. On the walls of the tube you can see the the different layers of the lava flows. The picture below is of the more viscous Helluhraun lava. these lava flows greatly differ from one another.
Our guide also told us about the legends and myths of the tubes. It is well known in Iceland that trolls and the hidden people (elves) do not get on. The elves are said to live in the lava fields. In the lava tubes we saw an elf ballroom, the whole room sparkling due to the crystals in the lava. The guide told us that the chandelier on the ceiling was a "troll’s skull" as seen in the picture below.
Not many people are aware of the lava tube explorations before they go to Iceland but we would highly recommend it. We chose to do it on a whim but it turned out to be one of the best adventures of our trip to the country.