Sunday, March 11, 2007


How does a geologist decide where to go for a holiday? He just looks at a geological map for something unusual, a type of rock different from the usual sandstones that Australia's made of. Granite, for example, is hard and so weathers slowly and is left sticking up after the sandstones have disappeared. Many of the headlands and islands along the coast are granite, or volcanic.

Undara, a volcanic area about 700km north of Moranbah, is world famous for its lava tubes. Lava erupted here less than 200,000 years ago, an eyeblink in Australia's billion year old landscape. Undara's lava didn't explode into the air like many volcanoes, because it contained less dissolved gas. Instead it flowed like water, flooding across the landscape and swirling around hills of 300 million year old granite, until it reached a river 160km away. The lava flowed through a network of tubes which kept it warm - it cooled only 1 degree per 10km. Once the eruptions stopped, the tubes were left empty, much as they are today.

The roof has collapsed in some sections, creating cool, damp pockets of rainforest in the hot, dry highlands. Because the lava flowed away, the volcanoes themselves are fairly flat, and are known as shield volcanoes. Much easier to climb than some of New Zealand's monsters!

Getting to Undara was a two day drive. I went north from Moranbah via some dirt roads, and found an old town called Mt Coolon. Before the Depression, Mt Coolon was a thriving gold mining town with a population of over 2500. Now only 50 or so hardy souls live there - it was 43 degrees when I got there! The remains of an old gold smelter dominate the town - an old chimney and rusted boilers and cogs lie to one side. I wandered around, before ducking into the cool, dark pub (also c.1920s) for rehydration and information on the town. It's less than two hours from Moranbah, so I'll definitely go back one day and poke around some more.

After Mt Coolon it was out to the sealed roads, and north to Charters Towers. CT is also an old mining town, but it's also a farming centre and so hasn't shrivelled up like Mt Coolon. A good polace to pitch the tent for a night. Right below the fruit bats' favourite tree, it turned out!

Ruins at Mt Coolon

Thunderstorm east of Charters Towers

Remains of a chimney on the hill above Charters Towers. It was destroyed during WW2, as it was considered a hazard to aviation.


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