Poking a paddock with a screwdriver might seem an unlikely way to meet a 95-million-year-old monster, but that’s how it works in outback Queensland. It is just one way the Australian Age of Dinosaurs (AAoD) team combs the topsoil for fossils in Australia’s most fruitful dinosaur graveyard.
Every day and night out here lays bare the immensity of life and time. Above, the night reveals a full sweep of stars never seen in the glare of cities; pinpricks of light stretching across space from ages past. And below are the bones, a metre under our feet but eons before our time, waiting to whisper their ancient secrets to whoever comes to listen.
Over three weeks every midyear, volunteers head to outback Winton to take part in AAoD’s public Dig-a-Dino programme, run by local graziers and expert fossil hunters David and Judy Elliott. It’s booked out up to three years in advance and many of the volunteer diggers are old hands (known as ‘duggers’), some on their fifth dig. As Judy Elliott says, “They’ve got dinosaur dust in their veins.”
The Elliotts know all about that. While mustering sheep in 1999, David struck the stray bone that led to Elliot, one of Australia’s biggest dinosaurs. It also led, in 2002, to the couple founding AAoD, an award-winning, non-profit organisation dedicated to Queensland’s Cretaceous past.
Among many finds, AAoD’s greatest hit is the double-discovery of two new species, the 15 m sauropod Matilda, and Banjo, a carnivorous theropod. Their mingled bones show they died together, stuck in a billabong in a prehistoric waltz of death. In 2009 Matilda became Diamantinasaurus matildae, the first Australian sauropod classified since 1933 (alongside Clancy, a separate find). Banjo made his formal debut as Australovenator wintonensis, a 5 m terror with huge hook-like killing claws. To picture it, “cross an emu with a goanna,” says Queensland Museum’s Dr Scott Hocknull, one of three palaeontologists (‘palaeos’) at the dig.
Dig-a-Dino’s current headquarters is a private property 60 km beyond Winton, in Central West Queensland. Diggers occupy the shearers’ quarters, which caps volunteers per weekly dig at 13. The dry terrain is open grassland and clayey black soil all the way to the horizon, rarely relieved by pockets of scrub. In dinosaur days it was all pine forests, swamps and mudflats. Underfoot, the Winton Formation of dinosaur-bearing dirt, exposed by erosion, dates back 95-98 million years, when Australia was still fused to Antarctica and New Guinea.
Today’s site, a new one, is a short drive to where a bone was spotted eight months before. Scraping the surrounding soil exposes a femur fragment that Judy Elliott, queen of dinosaur jigsaws, quickly joins to the surface bone.
Telling stone from bone can be tricky, but the basics are grasped fairly easily. Dinosaur bone has a subtly distinctive texture, often honeycombed by air pockets, and is typically brown with white splashes of calcium phosphate. It’s easy to confuse with petrified wood or pyrite, but the ever-patient palaeos happily identify whatever the diggers turn up.
Anticipation rises as David Elliott drives a front-end loader over to gouge a knee-deep pit. “I’m excited now!” says Trish Sloan, AAoD lab manager. “The Matilda site looked like this and we were there four years.”
The day ends with two dozen cows ambling over to watch as the team, now wielding rakes and shovels, extracts more fragments before knock-off. After a convivial dinner at the shearers’ hut, palaeo Matt White rounds off the evening with a talk on ‘reverse engineering’ clues to Banjo’s hunting methods by studying the locking mechanisms of eagle talons.
The loader’s first scoop the next morning fetches another chunk of femur, now 68 cm but still incomplete. The site has been nicknamed Oliver – Oliver with a twist, it seems, as raising him raises more questions than answers. The missing articular processes (projections where bones connect) are the key to identity type and without these the palaeos can only wonder what broad type Oliver belongs to. The flattened shape rules out a theropod (their limbs are circular in cross-section), but as Hocknull says: “This end doesn’t look right for a sauropod, that end doesn’t look right for an ornithopod.” It’s a mystery.
Fossils found here were once thought to be all lag deposits – remnants of layers exposed by erosion – until David Elliott drew a connection with his century-old fences toppling over. The posts were rising through the ground at about 1 cm a decade – and the dinosaurs were doing the same thing.
“It’s soil rotation,” he says. “A swelling pressure in all directions.” Expanding when wet, the drying soil shrinks and hardens, forming cracks through which particles fall. Lower layers are displaced upwards, inching buried fossils to the top. This explains the counterintuitive rule of thumb that says less is more when searching for dinosaur bones above ground. One or two decent pieces may signpost a bounty below, but a lot – particularly well-worn bits – often means the rest emerged long ago to be weathered away.
Elliott draws on a lifetime’s knowledge of the land to paint a picture of Queensland’s Cretaceous days. “The dinosaurs we find here tend to be sauropods of around 20 tonnes. Ones that get to that size have less danger from enemies and they grow old. Old animals don’t travel far from water and when they stop moving they lose condition. If they fall in, they’ll get stuck. Nothing lasts long if it’s not preserved under water or in mud, and a larger animal is more likely to get bogged.”
The diggers sift and rake, the scientists interpret and catalogue and David Elliott enlarges the pit with the loader, making a mullock heap to be inspected later – speck by speck.
By mid-afternoon the pit, now waist-deep, has revealed promising pieces in the lower siltstone layer, including a curving stretch of rib. “Make little cliffs around it and work your way in,” Trish Sloan says, coaching the diggers to isolate their discovery by screwdriver power.
A bone this size, encrusted and potentially frail, needs jacketing. This means removal to the lab in its rock casing by being dug around and wrapped in foil, newspaper and plaster. Dig-a-Dino always includes a visit to the lab at the Jump-Up, a forested mesa 12 km from Winton, which AAoD calls home. A statue of Banjo, jaws agape, guards the reception centre – his real bones (and Matilda’s) are on show inside.
A short stroll away, the iron-shed lab stores a vast fossil stockpile. The work is mostly ‘prepping’ – helping dinosaurs from their jackets by removing encrusted stone with pencil-sized drills. “It’s like colouring in,” says preparator George Sinapius. After a ten-day course, volunteers can book in to prep whenever they want.
Once the dig is concluded, Oliver is added to the 20 years of work from 55 sites now awaiting preppers, although his scientific description is underway.
“Oliver turned out to be an exciting find, a juvenile sauropod with particularly well preserved bones,” says David Elliott. “We ended up with a couple of excellent dorsal vertebrae, as well as several ribs, a scapular, humerus, femur and foot claw.”
AAoD also manages Dinosaur Stampede National Monument at Lark Quarry, 110 km from Winton, where 3300 footprints of about 150 dinosaurs spatter an enclosed rock face. Forever setting in stone an action-packed incident from deep time, the tracks show a big carnivore spooking a mob of smaller dinosaurs, who bolt for their lives across long-gone mudflats.
Lark Quarry adds a compelling jolt of reality to those broken bones in the black soil, revealing something they actually did one day as living, breathing animals. But, just like Oliver’s remains, a sense of wonder is never far from the surface at the dig, either. More than one volunteer points to the rib they’re coaxing from the pit and says, “You’re one of the first to see this in almost a hundred million years.”
The sheer enthusiasm for finding unknown giants in their hideaways is infectious; the sense of the adventure’s cultural importance is palpable. It’s as if by unmasking these prehistoric Australians we may somehow better know our own place in the grand scheme of things.