sand dunes

4 May 2016

Louis Hissink on sand dunes - provoked by Gary Gilligan's recent guest post. At .... we learn he was a geologist working in the deserts of western and central Australia. He was tasked with counting sand dunes in order to navigate (prior to GPS) so he got to learn a lot about them - and to realise the dunes were extraordinarily stationary. Unshifting. Just as well I suppose if you are going to count the sand dunes in order to know where in the desert you might be. As dunes are supposed to form as wind blown phenomena they should at least move around a bit. Nothing of the sort. They are paradoxically surprisingly unmoving.

Where did all the sand come from he asks. Some people suggest erosion rather than wind blown. Jury is out but dunes have been observed on Titan, a moon of Saturn. He mention's Harper's theory on desert formation but points out the theory fails to explain where the sand came from. However, the Australian Aborigines appear to have a tradition, or belief, that they actually witnessed the topography of Australia being changed - by the Rainbow Serpent. Whatever that might be. As they have lived in Australia for at least 50,000 years this is a distinct possibility. It is also clear that the Rainbow Serpent was firmly connected to the sky.

Topographically Australia is mostly low relief, even flat. Does this explain why so many of the drainage systems are blocked with sand - filling up streams and rivers etc. What did the Rainbow Serpent actually do? Did it carve out the channels and rifts in the ground (that streams then occupied) or did it provide the sand to block those channels (as Gilligan would claim). Hissink claims that not even torrents of water, or floods, are capable of shifting the sand blockages. This is a remarkable situation and the nature of the sand dunes he describes are completely at odds with mainstream views. He goes on to suggest the Rainbow Serpent was in effect a plasmoid cutting through the landscape by creating channels and rifts and in the process creating the sand that subsequently blocked the channels. It all sounds a bit like the lorg of the Irish god, the Dagda, pictured as a sort of contraption with its topmost part in the sky but running along the ground as if on wheels. This is also reminiscent of the Celtic concept of a heavenly plough creating furrows in the ground. As we are here into Indo European language origins we can visualise this as a universal theme - but did it give rise to the idea of ploughing the ground to plant seed. What came first - the heavenly plough or the human farmer?