I cannot begin to imagine what the first people who saw Uluru thought about it, nor can I remember reading what the first Europeans to see it thought. I have never actually seen it myself (I only got as far as Mount Conner, which is impressive itself), but living in Alice Springs for a while made me feel like I had seen Uluru, as it is plastered everywhere you look; a by-product of the tourist trade, I suppose.
Geologists know that Uluru is composed of arkose, a rock type like sandstone, but with a greater proportion of the mineral feldspar (as opposed to quartz) among its grains. This is a fairly unusual type of rock as far as sediments go, because feldspars weather and decay (to clay mostly) much, much faster than does quartz. This indicates that the arkose forming Uluru, was laid down relatively quickly. It was deposited in the Early Cambrian (about 540 million years ago) and the source of the sediment was from the uplifting of the Peterman Ranges, some distance to the South. Appropriately, this uplift event is called the Peterman Ranges Orogeny. As a sediment, the arkose was laid down with the bedding planes at or close to horizontal, but they have been tilted by significant folding and faulting of the crust, so that now the bedding planes are almost vertical. This faulting and folding event is termed the Alice Springs Orogeny and it occurred some 200 million years later, about 350 million years ago1.
The preceding paragraph is a very brief explanation of what geologists know about the formation of Uluru. However, when in Alice Springs, a colleague told me that a bus driver had told his busload of tourists that Uluru was a large meteorite that happened to plonk itself in the middle of the desert. Unfortunately, we never found out who the driver’s company was, so we were unable to at least attempt to set them straight. I say attempt, because people are not always amenable to being put in touch with reality2.
Some years later I bumped into a tourist who had been to Uluru and wondered how it got there. His explanation that he had formulated was that Uluru was a fossil termite mound. This was not as silly as it sounds because he had come to this conclusion after seeing ‘the brain’ on the side of the rock. That formation on Uluru does look like an excavated tunnel system, not too different to parts of some weathered termite mounds you see over central Australia (there is a whopper, at least 4 metres high and 3 metres in diameter on the Plenty River Highway). This tourist assumed that like many dinosaurs, termites were much larger in the distant past. After explaining to him what we do know about the formation of the rock, its age and the evolution of animals (termites weren’t around in the Cambrian, having evolved some 300+ million years later3), he apparently went away happy with having learnt something. It makes you feel good when someone thanks you for informing them.
Although his formulation may sound silly, he was actually using a method approaching that of science to come to a conclusion. He didn’t know much and his evidence was limited but he used his own observations to interpret what he was seeing. He, however, was not wilfully ignorant like so many who deny the understanding provided by science. When he realised that a geologist had more evidence and therefore greater knowledge of Uluru’s origins, he jettisoned his theory and embraced the modern geological understanding. That is in a nutshell, how science works. If evidence is available that shows a theory is incompatible with that evidence, you dump it and formulate a new one. The understanding we have doesn’t make Uluru any less of a marvel. Indeed, its history adds to its wondrousness.
Sources
- https://parksaustralia.gov.au/uluru/pub/fs-geology.pdf
- http://www.blotreport.com/australian-politics/first-brush-denialism/
- https://en.wikipedia.org/wiki/Termite
Many years ago I was watching some sort of quiz show on TV. The question was “what rock type makes up Ayer’s Rock?’–before the name Uluru came into general use. I cannot remember what the contestant said, but the “correct” answer given by the compere was granite–mind boggling, Incidentally I would have thought the source of the sediments making up Uluru was at least in part to the west. The Olgas (Kata Tjuta) comprise a breccia of similar composition to the arkose making up Uluru, but is much coarser and must have been derived locally. It depends on exactly where you are stratigraphically but the blocks at the Olga are boulders rather than sand sized.
Jim,
I hadn’t heard that one! I’m not sure of the age relationships between Uluru and Kata Tjuta. As far as I understand it, and as you say, Kata Tjuta is composed of conglomerate and the bedding is still horizontal. So, to say they are part of the same sedimentary system is difficult to demonstrate.
Well at one stage it was probably granite. I you go back far enough it was gas. Lol. Back in better days when on a BMR geol mapping trip I went to Uluru with a field hand who wanted to climb it. I’d already done it but on arrival at the start point he talked me into accompanying him. Trouble is I’d left my boots behind at camp and was wearing thongs! But young and stupid I thought okay (spent a lot of my early teens in bare feet) . Needless to say as soon as I got to the slightly steeper bit I had to discard the thongs. The combination of gravity, the friction from the coarse rock and my softish feet meant I had two large (and painful) blisters on the balls of my feet by the time we reached the top.
Jon,
I too have ended up with two massive blisters on the balls of my feet, but it was from a much more enjoyable pub-crawl around Copenhagen.
Only discovered after the hop-based anaesthetic wore off?
Jon,
I’d prefer not to admit anything!