Travelling Australia - Journal 2013
May 2013

Lark Quarry Conservation Park
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Lark Quarry Conservation Park is the site of a stampede by dinosaurs about 100 million years ago when herd of dinosaurs drinking at a waterhole were disturbed by a large carnivorous dinosaur which chased them for food. About 3,300 footprints have been uncovered in the trackways and dinosaur movements deduced from footprints (evidence doesn't indicate whether the larger dinosaur did actually catch and eat a smaller one but it certainly tried).

Lark Quarry is 110 kilometres by road south of Winton. Facilities are very limited. The dinosaur trackway is inside a large, purpose-built building with a car park nearby. Camping is not allowed, food and drink are not available and visitors must take their own refreshments. Fuel is not available. There is no mobile phone coverage and there is no UHF system available (the Winton area has a duplex UHF channel 1 system but it does not reach Lark Quarry).

Entry to the park is free. Entry to an orientation centre beside the car park is also free (toilets are incorporated in the orientation centre). Access to the dinosaur trackways is available only on guided tours for which fees apply. A couple of prepared nature walks (one moderate/easy and 500 metres long, the other difficult and 3.5 kilometres long) allow visitors to look out at the surrounding countryside and at the plants.

trackway shelter
Purpose built building protecting the dinosaur trackway.
Skartopus australis footprints Footprints of Skartopus australis which is described as a chicken-size dinosaur which was up to 75 centimetres long (nose to tail) with a hip height of up to 22 centimetres and head height of up to 25 centimetres. These heights indicate a posture with the head stretched out and only slightly raised. It ate insects, frogs, lizards, eggs possibly fruit and berries

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The name Lark Quarry was assigned in honour of Malcolm Lark, one of the excavators who is believed to have moved more rock than any other worker while exposing the footprints.

What Was There?
When the footprints were laid down about 95 million years ago the area was part of a river plain with swamps and lakes full of mussels, lungfish and crocodiles. Surrounding lowland were covered with tree ferns, conifers and early flowering plants. Grass had not yet evolved. Heavy rain was common, annual rainfall of one or two metres has been estimated. The climate was humid and cool

The footprint site was then a stream leading into the lake where lowering water level had exposed a patch of partly dried mud. Rain fell after the tracks were made and the lake rose covering the tracks with water and laying sandy sediment over them. Later flooding covered the tracks with metres of sand and mud. More sediment was laid down in millions of years and was compressed into rock. Then erosion slowly removed the overlying rock and the footprints were found to be looked at now.

The footprints have been carefully analysed and the species of dinosaur leaving them behind identified. Species identification gave investigators an idea of the diet and habits of the animals involved as well as their sizes and hence the length of their stride.

The footprints were discovered in the early 1960s and the first one was excavated in 1971. The main excavation in 1976-77 exposed the large trackways. By chance the rock deposited on top of the tracks had not adhered to the lower layers and could be easily lifted off. Sections of rock have not been excavated and there may be more footprints to be exposed in future.

footprint footprint
footprint footprint
The footprints were initially named Type 1, Type 2 and Type 3 and these names are sometimes still used. Top left is a Type 1 print; this was made by the large therapod which caused the stampede and is about 50 centimetres long; identity unclear until 2011. Top right is a Type 2 print made by the medium sized herbivore, reaching 1.7 metres head height (Wintonopus latomorum). The lower photographs are of the most numerous Type 3 (Skartopus australis) which is a small (25 centimetres head height) carnivore.

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What Happened?
Analysis of the footprints tells a story of a herd of more than 150 two-legged forest dinosaurs coming to the water in the afternoon to drink. According to signage at Lark Quarry, one species, described as Type 2, was a carnivorous animal (Skartopus australis) about the height of a chicken (up to 25 centimetre high and up to 75 cm long) which ate eggs, insects and frogs but was too small to be a threat to the other, larger species which was herbivorous. This was present in several sizes; small to medium ones were 4.5 metres long with head height of 1.6 metres while the larger ones were 5.5 metres long with head height of 1.7 metres. This herbivore has been nominated as Type 3 and covers a range of sizes. Sometimes this animal is described as "emu size" but this term is misleading; head height of 1.7 metres conforms but a length of 5.5 metres seriously challenges "emu-size".

Analysis of the footprints has led to a narrative of events with forest dinosaurs congregated at the water edge when a much larger carnivorous dinosaur, known as a therapod and related to the larger and better known Tyrannosaurus, approached the lake. Judging by footprints the therapod tries to intercept the smaller dinosaurs near the water, prompting the smaller animals to run across the mud flat, all running in the same direction and crossing the tracks left earlier by the therapod. The conclusion has been drawn that they were fleeing from the threatening therapod; hence use of the term dinosaur stampede.

When the initial footprint analysis was done in the 1970s the workers had to match dinosaur bones found at other sites with the footprints which were the only evidence they had. In the case of the larger Therapod which caused the stampede they used an accepted ratio between foot size and leg length which gave an animal with hip height of 2.5 to 6.6 metres although a more precise identification was not possible and the animals identity remained unknown.

In June 2006 the Australian Age of Dinosaurs Museum in Winton discovered a fossilised carnivorous dinosaur which was eventually named Australovenator wintonensis. Pending a formal scientific name the nickname of "Banjo" was assigned and has stuck in general conversation. Banjo was bipedal and equipped with ferocious teeth and vicious claws on short forearms but preliminary indications were that it was not tall enough to have been the Lark Quarry predator.

During 2009 and 2010 more of Banjo's recovered bones were processed at the Australian Age of Dinosaurs Museum. It became clear that this dinosaur had much larger feet and shorter legs than expected and could possibly be the Lark Quarry predator.

Bone processing then concentrated on completing foot and leg bones so the foot and leg could be reconstructed. Using imagery of the bones, staff at the Age of Dinosaurs Museum were able to digitally render the skeleton, muscles, skin and scales in 3D and this electronic model was used to make a life-size latex-foam model. As the final step, all filmed as part of a television documentary, the model was put into the tracks at Lark Quarry to see how well it fitted. The fit was so close that the identity of the Lark Quarry predator was accepted as Australovenator wintonensis, more widely known as Banjo.

Banjo A statue of Australovenator wintonensis outside the Australian Age of Dinosaurs Museum near Winton. Note the mouth full of teeth and the short arms with ripping claws. This is believed to be the species causing the dinosaur stampede now displayed at Lark Quarry.

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Getting There
Lark Quarry Conservation Area is 110 kilometres by road south of Winton. The road is clearly signed leaving town and distinctive red and yellow signs along the road report progress; there are "LQ" markers every ten kilometres so drivers are aware of their progress.

Leaving Winton and crossing the Western River's numerous channels the road runs across flat grazing land. At the time of this trip (May 2013) there were cattle grazing nearer Winton but sheep were more common further away. Although the sheep were head down eating something it was hard to see any grass on the stony plains they were on. Somebody later commented that the sheep looked like they were eating pebbles. Most of the road is unfenced and the stock often grazed near the road with associated risk of being startled by a vehicle and running onto the road, in reality sheep especially usually run away from the vehicles. Kangaroos and emus are commonly seen

Sign These brightly coloured signs are placed at several places along the road re-assuring travellers they are going the right way.

The road has an excellent bitumen surface and runs in long straight stretches several kilometres long until it reaches the foot of the jump-up (the mesa); the bitumen continues up the hill (reaching 245 to 250 metres) then the bitumen ended at the top of the hill 44 kilometres from Winton.

Open grassland with scattered timber common on the lower plain is replaced by thicker vegetation with trees to three and four metres high. Sheep could no longer be seen grazing. The gravel road was wide and had quite a good surface (but gravel roads can deteriorate quickly under traffic loads). Grids along the road marked the different properties the road passed through; all grids were well graded (but that doesn't mean they will always be well-graded). Along the gravel road were three sections of bitumen each four kilometres long and signed as "Overtaking Opportunities", a fourth stretch of roadworks in progress appeared to be another section of four kilometres of bitumen under construction.

airstrip sign Emergency airstrip sign. The straight section of road to be used as an airstrip is around the bend.

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The southern section of bitumen had been configured as an emergency airstrip with 1.5 kilometres of road wider than the rest, straight, and with vegetation cleared well back on both sides. Wide sections on both sides of the road at the ends of the 1.5 kilometre "runway" provided space for an aircraft to turn around.

Short sections of bitumen have been laid at the intersection of the roads to Carisbrooke Station and to Lark Quarry.

Lark Quarry Conservation Area car park
23° 00' 59"S, 142° 24' 46"E, elevation 236 metres.

Turn-off to Lark Quarry
23° 01' 39"S, 142° 27' 14"E, elevation 245 metres.

Emergency airstrip - southern end
22° 58' 16"S, 142° 29' 14"E, elevation 265 metres.

"CSI Lark Quarry" by Dr Scott Hocknull in Australian Age of Dinosaurs Journal Issue 10, January 2013, pages 24 to 39, describes the process of confirming Australovenator wintonensis as the Lark Quarry predator.
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