The paleontology lab processes fossils large, like this diprotodon skull that’s almost a metre in length…
To microscopic fossils from small marsupials or bats – these are micro-bat skulls.
Everything needs to be sieved…
Sorted (sometimes via microscope, as with these tiny teeth and jaws)…
And then classified. This generally involves comparing the fossils to known species. Teeth are the most useful fossils for classification as they are unique for every species.
This is the lower jaw of a small marsupial species, similar to a kangaroo.
And this is another diprotodon jaw, but for a much smaller species as it fits in a 10 x 10cm box.
These fossils may then be formally described as part of university research. The best go to university or museum collections. It’s this kind of research that helps paint a picture of what ancient Australia was like thousands and millions of years ago.
It’s been over 4 years since I made the field trip to the fossil sites of Riversleigh in North West Queensland. Back then, I helped the research team search for potential fossils in the limestone. The more bone-rich chunks of limestone were then bagged and sent to the University of New South Wales for further analysis.
It’s only last September that I had the opportunity to visit the paleontology labs at the university. And here are some of those bags of limestone!
And the limestone chunks themselves – with the bone chunks marked out.
Some of the fossil chunks can get quite large. All of this excess rock and dirt needs to be dissolved or washed away to reveal the fossils themselves.
To extract the fossils the rock chunks are immersed in a weak acid solution, similar in strength to vinegar. When limestone is placed in acid, the limestone dissolves, releasing carbon dioxide – that’s what’s bubbling away there.
Here’s what happens after a soak or two. Obviously, this is a process that needs to be repeated many times until the fossils are released, hence there were many, many tubs all over the lab.
It really hit me that we were going home when we came to the edge of the Gregory River – the boundary of the Riversleigh fossil fields.
This was my last glimpse of the lush, green oasis by the Gulf rivers.
It was also exciting the slip through the water like that. And the water was relatively deep too.
Half way back to Mt Isa, we passed by the gates of this station. It reminded me of Mr Thornton in North and South.
We glimpsed a couple of cowboys mustering cattle in the dusty yards, but I was most curious about whether the station was founded by a Mr Thornton or not. It would be rather exciting if a Mancurian industrialist did turn pastoralist in the Australian outback. It would be quite a story, anyway.
And that is the end of my journey to the Gulf. I’ll be back soon with a post about somewhere much closer to home.
On the way, we saw plenty of Brahman cattle, the main breed in the Gulf Country.
They’re not incredibly elegant, but they are hardy, and seem to have more common sense than other cattle breeds. For example, when faced with approaching motor vehicles, they know to get out of the way quick enough. Even the little ones.
The end of the week came all too soon – it was time to go home. At Riversleigh, the palaeontologists bagged all their specimens.
And then put them in the 4WD’s to bring back to Adels Grove.
There, they put the bags on to palettes, which will eventually be taken back to Mt Isa, and then transported by train back to Sydney.
For them, it’s really just the beginning of their discoveries – the extraction, and then the identification and write up are all still ahead. They certainly have enough work to tide them over until next year’s trip to Riversleigh.
There were quite a few species blooming in the Dry, only I wasn’t sure which were natives and which were introduced (and so a weed). Which, do you think, is which?
Isn’t it funny that they’re all a shade of pink-purple, out here in the arid areas?
Glimpsing their haul from the previous day, I saw that all the significant finds were neatly marked for sorting and transportation. There were piles and piles of rock, exposing jaws, teeth, and vertebrae.
A jaw bone.
Cross-section of bone (from a giant leg?).
As the morning drew on, the pile of ‘potential’ rocks grew, but as a novice, I couldn’t identify anything without professional help. Later, I found out that the team had found the jaw of a nimbadon (a sheep-sized diprotodon), but unfortunately for me it had already been bagged-up, ready for transportation.
What were inside those rocks? It was frustrating that unlike at Wellington Caves, where the fossils were preserved in loose sediment that could easily be washed away, extracting fossils from limestone required time and effort. I guess it’s like the difference between digital and film photography. Wellington was like digital photography, where you could almost instantaneously view your finds. However the fossils in Riversleigh limestone, like developing film, required the rocks to be transported back to the labs at UNSW, where they would be submerged numerous times in a weak acid solution. Eventually the limestone would dissolve to reveal the bones inside it. Like an expectant photographer developing film, hopefully I can one day visit UNSW to get a glimpse of this year’s finds. It would really round-off my Riversleigh experience.
I got to see more of the dig team in action the next day when we visited a site called South GAG Plateau. Early in the morning, there was a lot of scanning for potential sites. It also meant the carrying of equipment, including crow bars.
Unfortunately, there wasn’t anything being blown up that morning, so Lizard, the bushy-bearded explosives expert, wasn’t called to do anything more strenous than haul a few rocks.
That didn’t stop the eager palaeontologists and volunteers from wielding sledgehammers, crow bars, geo-picks, and shovels in an effort to extract more rocks.
After breaking the limestone into manageable chunks, they would carefully examine each piece to see whether it had bone (and hence ‘potential’).
What were inside those rocks?
At the working site, there were plenty of recently extracted rocks to look at, with plenty of bone.
But there were also plenty left in the ground. Like this cluster of bat bone fragments.
And things that weren’t even mammalian, like this stromatolite.
But the prettiest things were the flowstone from now eroded caves. They had some impressive swirls.
From above, the Riversleigh landscape seemed a bit uninspiring at first. It had none of the extraordinary coloured and shaped sandstone from Kakadu and Central Australia, or any extraordnary trees.
It was only up close that I learned to appreciate the different species. The gums with their pale trunks – different from the ones found in the Red Centre.
The acacia bushes, in bloom.
And other unusual flora.
But most common were the tuffs of spinifex. Sometimes they made eye-pleasing patterns on the hillside.