February 22 - the Great Artesian Basin

For a while now, we have been travelling over or on the edge of the Great Artesian Basin (GAB) - what an amazing phenomenon (the GAB, not our travels!). On our way to Yowah today we came across a series of mud (or mound) springs near Eulo. Such pressure-release valves as these, are a feature of the GAB - that’s a bigger story which I will leave to you to pursue for homework! Needless to say the water of the GAB ‘bubbling’ up through natural springs, such as these, or through drilled bores, is the life blood of arid inland regions like this and further south and west. 

If you think about it, much of the water of the GAB is really ‘fossil’ water having collected over millions of years. And because of the ageing process as well as high temperatures and pressure, the chemistry of the water is different to that of rain and surface water. As a result and because of  the relative isolation of most springs, they are habitat to some unique plant and animal species most of which are listed as endangered and thus protected. Fascinating creatures really, for example the ‘water-holding frog’ that spends most of its life underground sealed in a waterproof cocoon and the shield shrimp. 

The spring we saw was pretty dry, but the tops of the mud springs are usually soft and jelly-like (although the mound spring we found along the Oodnadatta Track some years ago had water in it - perhaps a different kind of beauty). However .... these mud springs occasionally explode making a sound loud enough to be heard for many Km. And no we are not going to hang around to experience it! 

My head is hurting - too much to absorb!

One of the mud springs at Eulo

Worth a read

Yapunyah tree Eucalyptus ocrophloia

The trees are pretty stressed here and so was Lindsay - bloody flies!

The Yapunyah tree (Eucalyptus ocrophloia) is gorgeous. When I saw these I thought they were Desert bloodwoods, which I love, but no.  These beauties seem to love to live near water. Their upper trunk and branches are a deep glossy red-brown. Their flowers are so abundant and rich in nectar, beekeepers from across Australia bring their hives to Eulo to collect the rich honey. I must look for it!