Queensland Road Trip, May 2022
Let’s go on a road trip! Come with us to Townsville and west on the Savannah Way to Karumba on an adventure in far north Queensland.
Around 190,000 years ago a giant shield volcano on the McBride Plateau erupted, forcing 23 cubic kilometres of lava to the earth’s surface. The fast moving lava flowed into a river bed and continued across the plain for 160 kilometres. While the outer layers cooled quickly and solidified, the molten lava inside continued to flow away, leaving huge basalt tunnels behind. The volcano is now known as Undara, which means long way in the local Ewamian language – the lava flow is the longest in the world.
Over time some of the tunnels collapsed, forming sheltering spaces for dry rainforests. The intact lava tubes provide the perfect habitat for dark-dwelling fauna like microbats, insects and small amphibians.
Undara and the lava tubes are now part of Undara Volcanic National Park and the wider McBride Volcanic Province, which contains 164 volcanos. Safety issues mean the lava tubes are only accessible on guided walking tours. Some contain high levels of carbon dioxide and many are difficult to negotiate.
Our guided walk started at Mikoshi Lava Tube, 46 metres long, 14 metres wide and 11 metres high. With a sturdy cable in hand for safety, we clambered down a jumble of fallen rocks to the floor of the tube.
Sunlight streaming in from each end shone across the walls of the tube, highlighting the layers of solidified lava.
At 293 metres, Wind Tunnel was much longer and the light only penetrated a few metres at either end.
We made our way into the tube by torchlight, carefully following in our guide’s footsteps.
She explained the geology of the tube system, her torch showing where the lava had moved and settled. In some places streaks of red iron oxide and white silica created beautiful marbling on the walls while elsewhere the stone was pockmarked with burst air bubbles.
A colony of little bent-wing bats lives in the darkest part of Wind Tunnel. We could hear them all the time, rustling and moving about on the ceiling eight metres above, but we only saw them for the briefest of moments. The guide lit up the roof for just three seconds; enough for us to see them but not enough to disturb their daytime rest.
As we left Wind Tunnel there was time for one last glance back into this natural wonder. It was hard to imagine that not so long ago, in geological terms, this was filled with a river of molten rock.
Joining Jo for Monday Walks