So, here's a first selection of the many beautiful rock types and formations on offer - these are all from the Wadi Rum area.
As you can see pretty clearly here, there are lots of levels of rocks in Wadi Rum - the mountains there are mainly sandstone, a kind of sedimentary rock which is made by layers of sand settling under water. Sandstone is pretty soft and is easily eroded into different shapes, which is what makes Wadi Rum's mountains so varied and beautiful. Under the sandstone is a base of much older and harder granite, and you can see this base layer in some of the mountains - this is part of the darker band at the bottom of the mountain above ...
Here is a closer look at some layers - you can see how different the layers are, which is apparently because of different conditions when the layers were being created. In this photo, in the bottom section are hundreds of very fine layers which were made by a very gentle lapping sea. Then you can see that the section above, where the hand is, does not have the same layers and has little stones in it - this shows much more turbulent conditions for a period of time. Then there's a different section again, with less even layers and some higgledy-piggledy lines above that (not the correct geological term I'm sure...). So each layer has a story to tell about the earth and the weather millions of years ago ... how cool is that!
Here are a couple of examples of different kinds of erosion in the sandstone - I love the way that some of the mountains look like they've had wax dripped all over them, and others look like they've been munched by small (or not so small) burrowing animals. Both the dripping and hole effects are different types of something called tafoni, which means 'small caverns' in Italian and is to do with water dissolving some of the calcium in rocks and drawing it out. It reminds me of some modern art - and can anyone else see a monster's head in the photo on the left? Or is that just me ...
This is a different kind of weathering of sandstone, where the lower layers weather faster than the upper ones and make mushroom-shaped stones. I've included this here because they look good and also have the best geological name I've come across so far - they're called hoodoos!
And here we have our (temporarily) resident geologist in front of some 'desert varnish' - this is when a sandstone surface is covered by a thin dark coating which looks like some kind of staining. It's actually caused by colonies of bacteria that live on the surface of rocks and deposit black and red oxides on the the rock surface. Apparently it can take 10,000 years for a full coating to build up ... and over the centuries these coatings have been scratched by passing nomads with all sorts of pictures and inscriptions, such as the Thumadic inscriptions on this rock (about 2,000 years old). Do you remember covering coloured paper with black wax crayon and then scratching a picture out of it? That kind of thing ...
And then there are the real and fake fossils ... in the above photo are what looked like some kind of tubular plant or possibly animal remains fossilized in a rock. To be honest, while there were definitely other kinds of fossils in the same area, we were not sure if these were really fossils or simply 'concretions' - which in sandstone is when minerals are deposited unevenly in the sandstone (any soft-rock geologists or fossil specialists out there who can help?) In the picture below, the bobbly bits in the rock (another non-geological term I think) are definitely concretions. (Don't know what kind of finch this is by the way, again if anyone can help?)
Next week - pretty stripy rocks ...
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