Tag Archives: coral reef

Windjana Gorge

Wednesday 11th to Friday 13th September

By this stage we were becoming old hands at breaking camp and we were soon on our way. It was 90km to the Gibb River Road and where  we headed west. We stopped at Imintji for some supplies. There was some smoke from bush fires to be seen but we never felt in any danger.

On the way from Monington to Windjana
Smoke from bush fires in the King Leopold Ranges

The Gibb River Road is largely dirt but it is characterised by occasional stretches of tar. Some of these are where the road is curvy but many others seem to be randomly distributed.

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Geological map of the Windjana Gorge area with our route to it from Mornington

As we got nearer to Windjana Gorge we recognised a well known head.

On the way from Monington to Windjana
Queen Victoria looks over Napier Downs

Shortly afterwards we passed a rubbish collection centre (where people can dump their rubbish from there cars and campers and keep The Kimberleys clean) and turned left towards Windana Gorge.

HERE is a link to our route from Mornington to Windjana. It is the GPS track I recorded en route. And linked to it are the photos taken with the actual spot they were taken! It is a .kmz file which you will need to save and then open with Google Earth.

The quiet camp site (i.e. no generators) was almost empty so we were able to get a good spot under one of the few trees on the site. It had a good view of the reason we had come to Windjana – the Devonian Reef!

View from our campsite at Windjana
View of the Devonian Reef from our camp site at Windjana

After setting up our tent and having a badly needed cup of tea, we set off in the evening light to have a closer look at the reef. The Lennard River has eroded its way through the reef but there is a shorter way into the gorge. This is through a short cave which runs through the reef.

The walk to the gorge
Chris taking the short cut through the reef to the Lennard River Gorge

We did not go far up the gorge as evening was approaching and there were a lot of freshwater crocs in the river who, while not deadly, need to be treated with respect! But we did see a fossil, possibly some sort of nautiloid. The books suggest that there are lots of fossils but we saw few – perhaps the good sites are not publicised so as to discourage collection by tourists.

Fossil in the reef
“Our” fossil in the reef – it looks very like the one on page 370 in Bulletin 145 (see below)

 

Thursday 12th September 2013

We were up at the crack of dawn and walked into Windjana Gorge. It was very quiet at this time and the gorge is rather beautiful.

HERE is the route and photos taken this day.

The banks of the Lennard River
The banks of the Lennard River

The banks of the Lennard River

The banks of the Lennard River, looking to the entrance of the gorge

This was the dry season so the river was very low and scarcely flowing. There was a great deal of sand so walking was uncomfortable for persons like us wearing sandals or thongs (don’t get too excited – that’s flip-flops for us Brits!).

The walls of the gorge
The walls of the gorge

Our reason for coming to Windjana was to look at the geology of the Devonian reef. The Geological Survey of Western Australia’s Bulletin 145 on the reef can be found HERE.

The bulletin will tell you far more than I can. Essentially it was a “coral” reef in the late Devonian period. Coral is in quotations as true corals were rare at that time but beasties which filled the same ecological niche were common and built something remarkably like a coral reef.

The Classic Face
The Classic Face. This is a panoramic shot created from five individual photos.

The following are links to the five photos which you can download. Warning: – they are large files! Photo 1Photo 2Photo 3Photo 4Photo 5.

At The Classic Face we see a cross section through the reef. If you think of the Great Barrier Reef you can see that The Classic Face is a well exposed equivalent.

The reef itself is the bit against which the sea works, forming breakers. Bits are broken off the reef and these fall seawards forming a dipping fore reef of bits of broken reef. And behind the reef is an area of protected, shallow sea – a lagoon, in which flat lying coral – the back reef, is deposited.  It gets uplifted (or sea level drops), eroded and then drowned again so another reef forms.

And then it all gets planed off so that the fore reef is at the same elevation as the reef.

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The Classic Face annotated. This is based on a sketch on page 351 of Bulletin 145

Above I have put in various boundaries taken from a sketch in the WA Geol. Surv. bulletin 145.  Consult this for an exhaustive discussion of the reef – it certainly impressed (and exhausted) me!

Freshwater crocodile
A Freshwater crocodile in the Lennard River

Having had a good look at the fossil reef we set off back to the camp site, passing many freshwater crocs.

Back at camp we set off for Tunnel Creek which is where a stream runs through the reef forming a tunnel which you can walk and scramble through. It sounds more impressive than it is. Photographically it did not inspire me at all and we have been to “better” caves.

At any rate I took no photos and my only memory is looking at the tour buses. Because of the high price of these tours most of the people on them are rather old, but with a sprinkling of young bloods keen to see the great outdoors. It must make for tensions between the young and fit and the old and creaky.

On our way out we met a group racing through the cave and then passed a group of elderly who had got into the shade and were waiting for the young ones to come back so that they could get back on board the bus.

Also on the way to Tunnel Creek we stopped and helped a couple who had a flat tyre. Actually we did very little – we just stayed till they had the spare on and were good to go. We might have been of use if they had not been able to get the tyre on.

Bower bird nest
A Bower Bird nest at the camp site

Back at camp we found a group of people who had found a Bower Bird nest, right in the heart of the camp. The male bird builds and decorates an elaborate nest to attract a mate. I don’t know whether this one did the trick.

 

Friday 13th September, 2013

HERE is the route and photos taken this day.

The boab prison tree, Derby
The boab prison tree, Derby. A hollow tree used as a prison.

The only thing of interest on the long flat drive was the Prison Boab Tree near Derby. In the late 19th century workers were needed for the mother of pearl industry in Broome and other places along the coast. So Aborigines were “recruited” (enslaved might be more accurate) from the Kimberley and marched to the coast. To discourage defection they were kept in places like the prison tree overnight on their march.

Soon we were in Broome where we booked in to a hotel for two nights.

Geikie Gorge

Monday 26th August 2013

We found ourselves a powered site at the Fitzroy Crossing camp site and were much impressed with the facilities. I was able to do some work on my photos on the laptop.

Fitzroy geol map
Geological map of Geikie Gorge Area with our track for the day. The gorge is at the top right of the map.

We got up early and set off for Geikie Gorge National Park.

The strange name comes from the Director of the British Geological survey in the 1880’s. Archibald Geikie never visited Australia, never mind Geikie Gorge. It was named by Edward Hardman, one of the first white men to see the gorge, who had previously worked for the Geological Survey of Ireland and who wanted to be the Western Australian Government Geologist.

I surmise that his naming of the gorge was an insurance policy. At that time the Irish Geological Survey was a sub-office of the British Geological survey. When the Western Australian Government refused to appoint a geologist at that time he returned to Ireland and got his old job back. I presume naming a marvellous geological feature after a possible boss did not do his prospects any harm!

But the poor man died shortly after re-starting with the Irish Survey. And he had applied for and got the Western Australian Government Geologist job – news of his death reached Perth shortly after it had been decided to offer him the job!

Moves are afoot to rename the gorge by its local aboriginal name  – Darngku.

HERE is today’s route and photos. Open with Google Earth.

The first thing you notice when you get to the gorge is the visitor centre and signs indicating the various flood levels of the Fitzroy River. Indeed some of the recent floods have overtopped the building.

At Geike Gorge
Flood levels at the Geikie Gorge Visitor Centre

And when we set sail on the Fitzroy River we readily believed the claims of the flood levels. The gorge is cut in a Devonian reef – a coral reef except that abundant corals had not yet evolved. The responsible creatures were calcareous algae and coral-like stromatoporoids, There were some early corals but these were mostly solitary ones. The rocks therefore are almost entirely limestone and this weathers to a dark brown colour – except where it has been scoured clean by flowing water.  The “tide mark” on the cliffs is rather high!

At Geike Gorge
The flood level of the Fitzroy River is shown by the top of the white limestone.

The freshly washed limestone shows fantastic shapes. It has been eroded and dissolved and looks wonderful.

At Geike Gorge
The wonderful shapes of the Devonian reef limestone.

The National Park closes in the wet season as boating on the river would be rather unpleasant. Some of the wildlife would also find it unpleasant, especially the Fairy Martins who build their nests on the undersides of overhangs which become submerged in the wet. They have to get their young out of the nest before the first flood.

At Geike Gorge
Fairy Martin nests, built of mud, on the underside of an overhang.

The other noticeable wildlife in the gorge are freshwater crocodiles. There are lots of them! These are the “nice” ones – a danger to fish, not to humans, although I still wouldn’t like to be nipped by one. The “bad” crocs are the Salties who see humans as lunch – we didn’t actually see a single one of these in all our time in Australia.

At Geike Gorge
A Freshie resting at the base of the cliffs.

The trip along the gorge was good fun and we saw lots of cliffs, birds and their nests and lots of Freshies. And we saw Trickie Dickie Nixon!

At Geike Gorge
In the wet of 2011 the water got up to Nixons nose!

Back in Fitzroy Crossing we paid my speeding fine at the Post Office – paying the fine was almost as easy as breaking the speed limit.

Then to the Crossing Hotel and saw a queue waiting for the bar to open! Most were aborigines. We looked at an Aboriginal Art exhibition at an adjacent gallery then bought some decorated boab nuts from an aboriginal gentleman sitting and working in the shade outside.

The Boab Nut Carver
Bob the boab nut carver.