00:00Glenn, I've heard all sorts of theories as to how these circles were made, including
00:13that they were somehow put there by aliens. You're not a proponent of the alien theory
00:18though, are you?
00:19No, certainly not aliens, Tim. Three more plausible theories. The first one was made
00:25by Professor Ted Bryant from Wollongong Uni, must have been about 20 or 30 years ago. His
00:32idea was that tsunamis that hit the coast here every now and then, the tsunamis have
00:37vortices in them, and these vortices are strong enough to remove the top layer of rock. And
00:46as the vortices spin, they remove the rock and form these circles. But that doesn't make
00:53sense because the circular structure actually goes below the surface. If you have a look
00:59at the side, the cross section of one of these circles, you can see that it goes down into
01:03the sediments. And so we've spelled that one. The second one is massive concretions. The
01:10structures are too big for a concretion. The concretion works out from the centre and moves
01:17out to the outside. These are too big for that. The third idea is that they were formed
01:24from shaking. Now the culprit is a dike just over here. It's quite a wide dike. It must
01:31be four or five metres wide. And when it was intruded, it's liquid magma. It's been forced
01:38up into the sediments. And as it's forced up, it creates a localised earthquake. The
01:45sediments shake as it's intruded and we get these circular structures forming. Similar
01:52to if you've got a wheelbarrow of concrete and you give it a bit of a shake, you get
01:57these circular formations in the concrete. The same thing has happened here in the sediments
02:02but it's on a much greater scale. So it's that dike which is the culprit of these circular
02:10structures. Are you 100% certain or do you think it's still a bit of a mystery? I can't
02:14be 100% certain but that's the most plausible explanation.
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