We took a tour to the larva tubes. They were interesting. Ok they look like caves and as caves goes there was no stalagmites or stalagmites growing. There were no animal bones imbedded in the wall or ground. There was no wall painting to marvel over. Sounds pretty boring doesn’t it? When you take a step back and think: 190,000 year ago the earth trembled as a volcano erupted sending lava flowing down the mountain. The air would have been thick with clouds of volcanic cinders and ash. The boiling lava would have carved a course of less resistance by flowing though the waterways sending steam to fill the air.
The caves are more interesting now.
To make the tube the lava flowed gently, like hot oozy think custard. When a slight slope to the land the lava move slowly, allowing the top part of the lava to cool forming a crust. More volcanoes added their own layer to help build a strong roof and the scorching lava continues on its way forming the tunnels. Over time the waterway reclaimed its old way. It washes away everything it could. Then one day thousand of year later someone comes along to find the tubes and though they were smart for doing so.
What surprised me was how natural the caves still were. A walk way had been laid to protect the ground and that was it. Tree roots hang from the roof or ran along the ground. There was not great embellishment to light up this or that.
The ranger pointed out different features with his torch, like natural art on the roof and walls. Or the lines on the wall left by the flowing larva.
He pointed out different marks on the wall and asked us what we thought they looked like. I said a love heart for one and he told me no one had suggested that before and that I was being romantic. He said most people say ‘a map of Australia’. I know it isn’t the best photo I have taken but I couldn’t see Australia in it.
We walked though one tube but it was in two sections and under a tube bridge. The tubes were only found because part of the tunnel had collapsed. (Many of the tubes still lay unexplored.) The tours run all year round and take about 2 hours. They run even in the wet season. Some times the tubes are filled with water, then depending on the depth of the water whether you take a swimming tour or a boat tour. I am pleased it was dry season. I don’t know how I would have gone walking waist deep in water into a dark cave not knowing what was lurking in the depth of it.
Facts about Undara
- Flow rate of lava – 1000m 3/sec, which is equivalent to 1500 semi-trailer loads per minute or enough to fill Sydney Harbor in 6 days.
- Area of landscape covered by lava – 1550km2.
- Amount of molten rock – 23.3km3
- Temperature of lava – up to 12200
- Direction and distance of flow – more than 90km to the north and 160 km to the north-west
- Aboriginal meaning of Undara – ‘long way’
- Undara is the longest lava tube system in Australia, and the longest recent lava flow from a single volcano in the world.