If you’re not into the savage beauty of extraordinary rock formations, then there’s nothing here for you. Move on…
Oh, still here? OK, then.
Thursday 15 August – Before anything else, some geological background to the Kimberley.
I’ll be honest, I didn’t know exactly what “The Kimberley” meant, except as the highly scenic destination for a lot of cruise ships. Courtesy of one of the onboard lectures, I have learnt a few basic geological nuggets.
- Everyone knows that bits of the Earth’s surface have moved around; at one stage most of the land was in a single great mass which had since drifted apart. What I learned is that Australia is not just one of these drifting land masses, but is actually composed of multiple cratons – micro-continents – which over the millennia have crashed into each other and got stuck together – “sutured” in geology-speak.
- It’s a law of geology that rocks accrete vertically, oldest, therefore, at the bottom
- When lumps of land collide, unsurprisingly the bits of land at the edges do not have an easy time of it, and compete for superiority. One edge “loses” and is either forced underneath the other, (a process called subduction) or over it (obduction).
- The Kimberley is the verbal shorthand for the Kimberley Basin, a craton which collided with Australia and got stuck to it around two billion years ago.
So, you can see that the land round the edges of the Kimberly basin is going to be full of these subductions.
Still with me? Oh, goody!
Today we had arrived at Talbot Bay, towards the left-hand edge of the Kimberley Basin. One would therefore expect the rock formations to be somewhat tortured by this subduction/obduction process.
One would be right.
Here is what the area looks like under the serene gaze of Google Maps.
Geologically, though, there’s a lot going on.
The land has been buckled and twisted in a very unusual way. Erosion has worked its way through the more easily weathered layers, thus exposing those underneath.
OK, so what? I hear you cry. Well, you get to see some rock layers that are normally buried under millions of years’ worth of other rock. More to the point, though, the landscape is visually arresting, particularly now I’ve set it up for you.
So, there now follows a large number of photos of rock formations. You may care to leave at this point in the symposium, or, alternatively, to skip to the bottom where something slightly less dull happens.
We cruised around for a couple of hours, giving us a opportunity to take lots of photos.
I hope you can see the extraordinary angles the layers have been buckled to – some are almost vertical and others remarkably twisted and distorted.
This is my particular favourite – the colour of the rock just blazed from underneath the darkness.
The darkness in all of these images, in many cases just above the water line, is caused by cyanobacteria. These would normally be a blue green, but when exposed to the light they go into stasis and their colour changes to dark grey or black until they are covered by water as the tides go up and down.
Ah, yes. The tides.
The tides are the cause of a phenomenon that pulls in tourists from far and wide. Some of them like us, would be in boats; others would take seaplane tours, from platforms rather unattractively parked in the middle of the bay.
What attracts them is the behaviour of the tidal currents through a couple of gaps in the rock, one of which
is sufficiently narrow to create whitewater rafting-style currents.
But not for us, sadly.
Once again, that old devil moon was spoiling our fun; we were here at neap tide, so the thrilling flood looked more like, well, a dribble, really. It may not have looked like much, but the guides attempted to make things more exciting for us by jockeying for position in the stream.
Had we been here at spring tide, this is how it might have looked.
Now you can see why it’s called the Horizontal Falls.
It is – at the moment – a popular tourist activity to race up through the channel. Our Zodiacs did not, out of respect for the customs of the indigenous tribes, for whom this area, traditionally called Garaan-ngaddim, is a powerful, sacred place; their belief is that boats that pierce these gaps disturb Woongudd, the serpent who creates this wonder by gliding between the cliffs.
Others at the scene were less respectful.
This was a craft from the luxury cruising ship True North
which was in the area at the time.
The practice will fairly soon be banned. Out of respect for indigenous customs? Or because there was an accident a couple of years ago? Your call.
In any case, it was just as well that none of the passengers described in that accident fell into the water;
this was a very large crocodile which we spotted further up the bay.
As well as the croc, and a couple of crabs and mudskippers, which I totally failed to get decent pictures of, we saw a plant called the Kimberley Rose.
It’s a deciduous tree, also known as the Sticky Kurrajong, or Brachychiton viscidulus
to grown-up dendrologists.
The expedition wasn’t the dramatic thing it might have been at spring tide, but the area is beautiful and the rock formations very impressive.
The morrow holds in prospect a visit to Bigge Island. On the other hand, I’ve developed quite a severe sore throat. I hope that doesn’t presage anything unpleasant…