How Winton's dinosaur footprints were saved from the Queensland floods

Updated

The race to rescue 95-million-year-old dinosaur footprints from the elements in the Queensland outback.

Welcome to Karoola: a property around an hour-and-a-half's drive from the town of Winton in central west Queensland.

In this part of Australia, a single farm can be the size of a small nation.

Today, the area is drowned in floodwaters after recent devastating rainfall across Queensland. Karoola itself received around half a metre of rain.

But step back to last September and it's a completely different story.

Scattered among the tussocks of spiky grass are traces of animals unable to survive, like the skull of a young red kangaroo lying in the dirt, scraps of ruddy fur still clinging to the bleached bone.

We're certainly in the right place to find evidence of long-dead creatures, but it's not kangaroos we want.

Our items of interest are almost 100 million years old.

They're dinosaur footprints, stamped in a sandstone slab on a parched creek bed.

A find of a lifetime

The Winton Shire's current population hovers around just 1,600, but it is home to a disproportionately large slice of Australian history.

Banjo Paterson penned Waltzing Matilda while visiting a cattle station in the area in 1895. A quarter of a century later, Qantas was born at the Winton Club in town.

And geologically, this region is a dinosaur goldmine.

Let's turn back the clock 95 million years. The Australian continent, not long broken free from Antarctica, was inching its way towards the equator.

What is now western Queensland could not have looked more different.

Lush, green floodplains covered with forests and ferns attracted insect- and plant-eating dinosaurs which, in turn, drew the carnivores.

Sometimes, if one of these beasts died on a mudflat, gently rising and falling water would cover the corpse in sludgy sediment.

Over aeons, that sludge turned to sandstone and the bones and teeth within became rock.

Now erosion has sloughed away the softer sandstone, exposing the fossils and, in some cases, allowing them to be literally picked off the ground.

Mike Elliott knows the thrill of finding them better than most.

His family owns Karoola and, with their other two properties, their range covers around half a million acres.

Mike's father was a prolific fossil hunter, once finding a big dinosaur bone sitting exposed on top of a ridge.

And as a youngster, Mike remembers scanning the property for bones while he and his father were out rounding up livestock.

"I think we spent more time looking at the ground than we did mustering these flaming sheep!"

He hands me a dinosaur tailbone, one that was discovered on Elliott land. And even now, fossickers can find slabs of petrified wood — remnants of forests that grew here 95 million years ago — strewn over the dusty ground.

But despite having ridden over this part of Karoola plenty of times over the decades, neither Mike nor his dad knew about the footprints in the creek bed.

The end of the trackway, peeking out from under a layer of sand at the bottom of a dry creek, was first spotted by an eagle-eyed caretaker a couple of years ago and subsequently confirmed to be dinosaur footprints by a palaeontologist.

A larger swathe of the trackway has been exposed since. Massive floods in March 2018 swept away more sand but, in the process, cracked a patch of the precious prints.

Saving the damaged area is what has drawn a 20-strong group of palaeontologists and enthusiastic volunteers to Karoola, most travelling thousands of kilometres from Victoria for the privilege.

And while water may have helped bring the prints to light, it could also mean the end for the crumbling section.

"We never know when we're going to get the next big flood," Mike says.

So begins an excavation of a lifetime: to remove the damaged section of the trackway and relocate it to the Australian Age of Dinosaurs museum on the other side of the town of Winton.

No instruction manual for a job like this

Three types of dinosaur wandered over and left their footprints on the mudflat all those years ago.

There was a tiny insect-eater that scampered around on two legs ...

... a slightly larger two-legged animal that ate plants ...

... and a sauropod — a massive, lumbering, four-legged herbivore that looked a bit like a brachiosaurus.

Sauropod footprints are few and far between in Australia, and these — each of which is around a metre wide — look to be some of the best-preserved sauropod tracks in the country, if not the world.

This is not your average dinosaur dig and it requires an equally unusual health and safety briefing.

Leading it is the museum's operations manager, Trish Sloan: "But everybody calls me Tricky."

Alongside the standard warnings about the dangers of heat and local wildlife — plus the arduous work itself — there's another menace lurking.

There is a "bush dunny" at the dig site, which is nothing more than a wooden box with a circle cut in the top, placed over a hole dug in the soil.

"Redbacks love it," Tricky tells the group, "and you're not going to use it until I come back with an empty can of surface spray."

Coordinating the logistics of the dig itself is David Elliott. David and his wife founded the Australian Age of Dinosaurs museum in 2002.

Like Mike — his second cousin — David's a grazier out here, and an old hand at the fossil game. Among other discoveries, David famously found bones belonging to Savannasaurus elliottorum on his property, Belmont, near Winton in 2005.

But until this dig, David's excavation experience was limited to fossil bones, not footprints.

It's not just inexperience working against him — there's time pressure too. He only has two weeks or so to lift the footprints away from the creek bed, onto a truck and into the safety of the museum, because that's how long he has the volunteers' helping hands.

It's too big a job to do alone.

But that didn't stop David from experimenting with a few ways of lifting 95-million-year-old, water-damaged sandstone before the volunteers arrived.

"We really want to preserve the integrity of the tracks — we don't want to just tear them up and go and plonk them on the ground somewhere," he says.

And because the sandstone slab is relatively thin — "only around a foot thick" — he first tried slicing underneath the rock into the sandy soil below using a chainsaw.

It was slow going, not to mention dangerous. He soon gave that up.

Next, he tried drilling holes through the slab and lifting it on steel rods threaded through.

But "the sandstone is so dry and so fragile, it's just crumbling", David says.

"I thought, we're going to put this on a trailer and drive it about 90 kilometres up to the museum ... by the time we get to the other end, it's going to be in a bucket."

So the new plan is to treat the tracks like big dinosaur bones: chip away underneath the footprints until they are attached to the ground by a thin base.

Forget what you've seen in Jurassic Park, where palaeontologists gently whisk sand away from fossils with brushes. This is hard yakka, requiring brute force that only a jackhammer, power saws and David's trusty chainsaw can bring.

The prints are covered in plaster and, when that's dry, the trackway sections snapped off and driven away.

Once at the museum, they'll be put back together like a jigsaw in the same orientation they were found on Karoola, and the plaster jackets will be removed from what David calls a "once-in-a-lifetime find".

New chapter in Australia's dinosaur story

But even before the plastering begins, there's plenty of science going on up the other end of the trackway.

Steve Poropat, a palaeontologist at Swinburne University, has a crew of researchers at the site from Victoria and South Australia to examine the sauropod tracks that aren't at risk of being damaged, along with the other two, albeit much smaller, sets of footprints.

Like many people, Steve was obsessed with dinosaurs when he was a kid. Unlike most, he turned it into a career.

For him, working on the Karoola trackway is a dream.

"You don't know how to contain your excitement," he says of how he felt upon seeing the footprints for the first time.

And they are exciting. The footprints have retained exquisite signs of ancient anatomical features.

You can see ripples and cracks where the sauropod pushed its foot into the mud, the texture of which was like potter's clay at the time.

Then, when the beast lifted its giant foot to take the next step, it dragged its claws in the mud — yes, those enormous dinosaurs had toenails — and the blob of mud that stuck to the sole of its foot dropped back into the nearly metre-wide footprint.

The claw scratches and mud blobs are clearly seen in the trackway, even today.

After taking measurements, sketches and more measurements, Steve and his team crunch the numbers to work out the creatures' heights and how fast they were travelling over the muddy terrain.

They calculate that the set of tiniest tracks — around 15 dainty, three-toed footprints, each around 4 or 5 centimetres wide — was left by a chicken- or turkey-sized dinosaur trotting along at a decent clip, about 10 to 11 kilometres per hour.

"Definitely not at full tilt, but a fair pace. Especially considering it's crossing a mudflat — it probably didn't want to stop, or else it would have gotten bogged," Steve says.

There weren't quite enough footprints to find out how fast the middle-sized dinosaur moved, but its "minimum height was 50 centimetres at the hips, we think it was probably taller".

And the sauropod?

"This is really cool," Steve says.

"Each [footprint] is 3.3 metres from the next one. Based on that, you would imagine, well, the animal's got to be at least 3.3 metres tall at the hips to take such a long stride, so fairly sizeable.

"And of course, because it's a long-necked sauropod, the head would be even higher."

The beast wasn't in a hurry, either.

"In this case, it's going at a nice slow pace — around 5 kilometres an hour," Steve says.

He suspects the sauropod species was Diamantinasaurus matildae, and measured around 18 metres from nose to tail tip.

Even the ground beneath the trackway tells a story.

Lisa Nink, a PhD student at Flinders University studying Australian megafauna, notices different coloured layers as she helps scoop out the sediment underneath the footprint slab.

"This is important because as well as how the dinosaurs moved, we also like to know about the environment they were living in," she says.

"By extracting sediment samples from within the footprints themselves, it gives us an idea of what the environment was like when the dinosaurs were walking through there."

Detailed analysis of those sediment layers may yield pollen grains, for instance, to tell palaeontologists about the plants that once lived there.

Safe and sound

At the end of each long day, everyone heads to the nearby property of Elderslie, where they're staying in the shearers' quarters.

Besides being next to Dagwood Station, where Paterson wrote Waltzing Matilda, Elderslie also happens to be a famous fossil property.

It's the discovery site of three of Australia's 20 or so dinosaur species — Australovenator wintonensis, Wintonotitan wattsi and the aforementioned D. matildae — which were unveiled in 2009.

After dinner, the group gathers around to chat about the day to the soundtrack of an acoustic guitar strummed outside.

And after two weeks — well, more like three in the end — the most delicate part of the trackway, the region at risk of water damage, is safely shifted to the Australian Age of Dinosaurs Museum.

The rest of the trackway will eventually make the trip to the museum too, but it's more stable so there's less of a rush.

Steve is relieved and happy that the most delicate section is finally sheltered and intact.

"To get it all out of the ground … is fantastic," he says.

This won't be the last time that a landmark discovery emerges from this region's mighty cycle of wet and dry.

The Winton Shire has all the right ingredients to present palaeontologists with more dinosaur footprints, and there's a hell of a lot of land out there.

With the restless assistance of the elements, it's just a matter of when they're unearthed.

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Topics: science-and-technology, palaeontology, dinosaurs, fossils, winton-4735

First posted