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Canadian Deb Bain found marrying an Australian and coming to live on his sheep farm in western Victoria “very cool”. But what’s even cooler, says Australia’s former Rural Woman of the Year, is the gentle rise that gives the family’s property 50 kilometres west of Ballarat its name, Stockyard Hill.
Unassuming in size and shape, Stockyard Hill is, nevertheless, a volcano. Its technical name is a maar, a crater created by large explosions when hot magma came in contact with ground water. A maar characteristically fills with water to form a shallow lake. I visit the crater is dry, as if defying the definition.
In Deb and David Bain’s home hangs a photograph showing the crater filled with water after rain.
Researcher Julie Boyce has identified up to 23 ‘new’ volcanoes in Victoria.
Stockyard Hill lies within what geologists call the Newer Volcanic Province, stretching from Melbourne to Mt Burr, northwest of Mt Gambier in South Australia. Within this enormous field are 437 known volcanoes. “Volcanoes have a very distinctive morphology (shape),” says Julie, and she’s right; once you know what to look for, you start seeing them everywhere.
Such as within Melbourne’s commuter belt, at Organ Pipe National Park, near Calder Raceway. Its spectacular hexagonal columns of basalt are part of a massive lava flow that filled a valley about one million years ago. The car park sits on top of a scoria cone. This now almost unrecognisable volcano once threw gas-rich molten rock in explosive eruptions into the air.
Heading north on the Calder Highway, I get only as far as Diggers Rest before getting sidetracked, down small country roads. Ordinary solitary hills become, with knowledge, something else. Imagine ash clouds mushrooming; lava exploding out of vents; rivers of molten rock burning everything in their path.
In Lerderderg State Park, a rough track leads to the top of Mt Blackwood. Clumps of basalt, overgrown with grass, make walking difficult but also identify it as a volcano.
The view is over the thick bushland. Behind it lies the spa country, where mineral springs feed a booming tourism and wellness economy. Volcanoes also dominate the landscape. More than six million years ago sticky lava oozed out from vents in the Macedon Ranges, congealing in places and forming large domes, of which Hanging Rock and Camels Hump are eroded remnants.
Volcanic riches unknown
“I’m amazed lots of Victorians don’t even know they have volcanoes here”, says Julie Boyce. “It’s one of the best volcanic areas in the world. We have lava shields, we’ve got scoria cones, we’ve got tubes that you can walk through. There is a vent at Mt Eccles (near Portland) where you can abseil down into it.”
Just a few kilometres north of Hepburn Springs is another extinct hill of fire, Mt Franklin. The crater, once a hellish place, is now an idyllic picnic and camping spot with large shady trees.
Past Mt Franklin, the route to Clunes is down small country roads. Along one, the unsealed Ullina-Kooroocheang Road stand the prominent Mt Kooroocheang and Mt Moorookyle. Their dome shapes identify both as volcanoes.
In Clunes, the story is about gold mining, but keep heading west towards Lexton and volcanoes again gain the upper hand. Mt Mitchell and a handful of small cones, most of them topped with wind turbines, enter centre stage.
The meaning of dry-stone walls
All along this tour, dry-stone walls of basalt rocks are sure-fire indicators of the local volcanic nature, such as at Stockyard Hill. Long stone walls, expertly built in the 1850s by the Dunns, an Irish family, announce the homestead and give clues to the geology of the place, which plays a vital role in Deb and David Bain’s fortunes. “Our farm is dominated by the volcanics,” says David. “Our limitations are due to the volcanics and all our advantages are due to it, too.”
From Stockyard Hill the route keeps west, past Dunkeld and down to a prominent volcano at Penshurst: Mt. Rouse. The panorama from the top of this volcano is breathtaking. To the north is the jagged skyline of the Grampians. To the south the flat plain ends at the Southern Ocean, 60 kilometres away. To the west a solitary mountain focuses the view, while to the east the plains and hills fade into the late evening haze.
Even for those with no geological interest, the view is stunning. For those in the know, however, it is a revelation because you are looking at one of world’s largest basalt plains. The prominent lone mountain in the distance is a volcano called Mt Napier, 20 kilometres south of Hamilton. The distant hills to the east are also born of fire.
As is Mt Rouse, below which lies Penshurst, a place of pilgrimage for volcanophiles thanks to its excellent Volcanoes Discovery Centre, the only one of its kind in Australia. Mt Rouse is special indeed. “The 300,000-year-old volcano,” Julie Boyce says, “erupted three chemically distinct magma types, as a lava field from gas-poor magma and scoria cones from gas-rich magma, from at least eight vents.” She made this complex volcano the centrepiece of her PhD.
Then there is Mt Napier and a 15 kilometre-long lava flow down the Harman Valley. An unusual feature here is the Wallacedale Tumuli, around 50 basalt mounds that rise like solidified bubbles up to 11 metres above the lava flow. West of Mt Napier are the Byaduk Caves, again volcanically created. And then there is Mt Eccles with its crater lake, a lava canal and a natural bridge.
Mt Rouse’s eruption has influenced other places, too.
Near Port Fairy is Tower Hill, a state game reserve to which visitors flock to watch kangaroos, koalas, black wallabies, echidnas, emus and a large array of birds in a natural setting. Yet this peaceful and idyllic park is the result of unimaginable violence. It is also John Sutherland’s “office”. A guide at Tower Hill, he explains: “This volcano started about 35,000 years ago and erupted with a crater about three kilometres in diameter. When the magma pushed up, it went into the ground water.”
The collision of super-hot magma with this water had dramatic consequences. “Magma is over 2000 degrees,” John points out. “Water boils at 100 degrees and steam takes up 2000 times the space of water.” The result was apocalyptic. Colossal explosions ripped the ground apart, sending enormous ash clouds in to the sky. At the rim of the crater, these ash layers are exposed for everyone to see. Ash, says John, was deposited all the way to Warrnambool.
Signs of restlessness
Are we likely to get a repeat performance soon? Deep underground there are signs of restlessness. “We call it an active volcanic province,” Julie Boyce says, “because around the southern areas and around the central highlands we get carbon dioxide from the mantle. Surveys show that there is a little bit of a partial melt. So the mantle is very hot and there are signs that it is still active.”
On the way back to Melbourne, a short detour at Terang leads to Noorat, the birthplace of writer and humanist Alan Marshall. For volcanophiles however, Mt Noorat, just behind the small town, is the real destination. A short walk brings me to the rim of a perfect crater.
Further to the west, close to the shores of Lake Corangamite, lies the 8000-year-old Red Rock Volcanic Complex. “It erupted from 40 vents and contains not only lava and scoria, but also maar deposits,” Julie has explained to me, putting this volcano firmly on my bucket list. Red Rock has a staggering 20 of these bowl-shaped depressions and is the final highlight on the geological journey through Victoria’s volcanic field.
I remember Deb Bain’s enthusiastic statement and I agree with her: volcanoes are very cool indeed.
If there’s a sudden hill in a flat landscape, it’s likely that lava built up the small hills at a vent.
A rounded lake with a low hill most of the way around is likely to be a maar volcano, where an eruption created a hole in the ground that became a lake.
A hill with rounded edges and a dip in the middle is likely to be a volcano.
Hard grey-blue rock with some holes in it is most likely basalt. The nearest hill could be a volcano.
A hill that has lots of black or red rocks full of bubbles is a volcano. The bubbly rock is known as scoria.
Dr Julie Boyce, Monash University
If you want a base when exploring volcano country, try RACV Goldfields Resort at Creswick. The resort is an ideal central point, with Ballarat, Daylesford and Clunes each less than a half-hour’s drive away.
Members save 25% off accommodation at this and all RACV resorts in Victoria, Queensland and Tasmania. For details, go to racv.com.au/resorts
For discounts and savings at attractions and businesses in the area, go to racv.com.au/sycas.