OZ +7: Built on sand...

Fraser Island is just beautiful.

It's made entirely of sand; in fact, it's the largest sand island in the world. This means that nothing should grow on it, as there's no soil, and no water should flow on it and there should be no lakes, because sand is porous.

But as Alan, our guide, pointed out. "Mother Nature finds a way..." (I think this was also Jeff Goldblum in Jurassic Park...) First, let's do plants. The island is virtually covered with forest...



Here's the primary school geography: this happens over thousands of years because very hardy salt-water loving plants colonise the dunes closest to the sea. They die and leave decomposing plant matter, which we all know becomes a thin layer of soil. A second wave of plants uses this to grown and so on... Eventually, the whole island is covered in many different types of forest...



Eventually, sand blown in from the eastern shore creates enormous, mile-long dunes which reclaim the forest and bury the trees...



Then we have lakes... There are two types on the island. One is formed because all the rain water which has ever fallen on the island soaks through the surface and forms a gigantic aquifer beneath the surface. Where the sand levels off to the top of the aquifer, water emerges. These are called window lakes, because they are a window on the water stored in the sand - 40 times more than all the water in Sydney Harbour.

The second type of lake is called a perched dune lake. There are only about 80 of these in the world and Fraser Island has 42 of them. The most touristy is Lake Mackenzie...



The sand is so white and the water so clear. (The sky is so blue as well, but I didn't want to start writing poetry by accident...) Perched dune lakes are high up and are formed when a sand bowl is lined with plant debris and effectively becomes waterproof. (Mr Miller, my secondary school Geography teacher would be so proud...)

All the roads on Fraser Island, or to give it its Aboriginal name, K'Gari, are sand roads and are hard going even in a 4WD. But the eastern shore, Seventy Five Mile Beach, is for all purposes, a motorway. Vehicles bomb up and down it, and legally, the rules of the road still apply - you have to drive on the left. Overtaking allowed...



The beach is also the final resting place of the SS Maheno - an Edwardian cruise liner built in Dumbarton. No-one died when she ran ashore in the thirties, but she was even more severely damaged when the Aussie Air Force used her for bombing practice...



For the moment, the wreck is stable and you can explore it close up, at least with eyes and cameras. The likelihood is that it will disintegrate and become dangerous within a few years and may have to be taken away or dismantled and buried completely. Enjoy it while you can...

OK, finally, streams - or creeks. Again, these form because of the pressure of the water held inside the island forces water out at sea level. They look strange because they have sandy river beds, but are beautifully clear. And the water is perfectly safe to drink, having been through the biggest and most effective sand filter in the world over a period of thousands of years.



There's so much to say about the island - no kangaroos, wallabies or koalas; but dingoes and monitor lizards and wolf spiders (2cm long and can kill you) in droves - all of which we saw. In the case of the spiders, on a night ranger-guided tour where you spot the spiders by shining a high-powered torch into the bush and look for the eyes shining back.

Creepy...