Victoria’s Cultural Cornerstone – Literally!
Melbourne is a beautiful city, anyone can tell you that. And not just due to its elegant skyline; one could easily spend a day only touring the laneways and historical buildings of the city. And if that person was paying close attention, they may have noticed a common thread in many of these sites: they are constructed from the same material.
This, of course, is Victoria’s famous “Bluestone,” so called after its steely blue veneer. It is a stone that has been a prized for its hardness and durability since the 19th century, when the Victorian gold rush saw a huge influx of fortune seekers. With the colonies rapidly expanding, building material was in great demand, and so bluestone was quarried from huge deposits in the surrounding areas.
Some of the most famous of Victoria’s historical buildings are constructed from bluestone. Going clockwise: Melbourne Grammar School (credit: Donaldytong via Wikimedia), Saint Paul’s Anglican Church in Kyneton (credit: Diverman via Wikimedia), Old Melbourne Gaol (credit: Bidgee via Wikimedia), St Patrick’s Cathedral (credit: Donaldytong via Wikimedia).
What Melbourne was built upon.
In Melbourne, and many other Victorian towns, Bluestone was used as the foundation of many buildings and was extensively used as cobblestone. It has proved itself to be extremely robust: take the Old Melbourne Gaol for example. Constructed in the 1850s, only an occasional light wash is needed in order to maintain it. Even today, bluestone remains ever popular: next time you’re in the CBD, look down. Chances are you’re treading on bluestone pavement!
But what is bluestone exactly?
Well, as it turns out, Victorian bluestone is actually basalt; a volcanic rock that spewed forth as lava millions of years ago, then subsequently cooled. These eruptions occurred remarkably recently: beginning a mere 4.5 million years ago and continuing intermittently until around 4000BC. While these time periods may seem unimaginable from a human perspective, in geological timescales they are a blink of the eye. Even so, this series of volcanic activity managed to produce a huge amount of lava and ash, creating what is now known as the Newer Volcanics Province. It is the cooled lava from the province, now basalt, that is bluestone.
Wait a minute: Australia has volcanoes?
Indeed, it does! While Australia has the deserved reputation for being flat and tectonically inert, there are hundreds of extinct volcanoes dotted across the South-Eastern region. These are the volcanoes that created the Province and are also responsible for some of the area’s most recognisable natural landmarks!
Mostly flat and featureless, driving through the Victorian countryside can be a bit of a drag. However, occasionally conspicuous mounds will appear, rising comparatively high into the air to offer a refreshing change in scenery. These are scoria cones, often optimistically called mountains. They can rise to be several hundred metres high and are actually mounds of ash and volcanic rock created by brief, violent eruptions. The most well-known of these include Mt Sugarloaf, Mt Elephant and Red Rock Lookout.
When creating these scoria cones, lava can sometimes overflow and spill out over the landscape. In some places these lava flows accumulate into massive deposits of basalt, forming the bluestone quarries throughout south Victoria.
These scoria cones are found throughout south-eastern Australia, and in Victoria especially. At Red Rock Lookout, maar lakes can be seen as well. Going clockwise: Mt Sugarloaf (credit: denisbin via Flickr), Mt Elephant (credit: Mattinbgn via Wikimedia), Red Rock Lookout (credit: Sean O’Brien via Wikimedia)
Crater lakes leave an explosive impression!
Often occurring close to these scoria cones are maar crater lakes. They form when magma rising from within the earth encounters groundwater, causing enormous explosive eruptions of steam and lava. The huge hole left behind forms the lake, and the ejecta rains down and forms scoria cones. Famous maars that are a part of the Newer Volcanics Province include Lake Bullen-Merri, Lake Gnotuk and Lake Purrumbete.
Surviving through cultural memory
The most famous maar lake in Australia is also a part of the Province. The Blue Lake of Mt Gambier, in South Australia, erupted as little as 6000 years ago. This is so recent that many believe that the actual event is still remembered today.
There are several aboriginal stories from the region that bear remarkable similarities to the events that must have transpired. The stories have been passed down orally for thousands of years. They detail the earth rumbling, cracking and heating, the air filling with dust, and ear-shattering shrieks. Interpreted by them to be the works of the Rainbow Serpent and other folkloric characters, it could also very well be an eyewitness account of the end of Australian volcanism.
Future volcanic eruptions: should I be worried?
After all this talk about volcanoes and explosions, some of you may be worried. If these eruptions have been occurring for millions of years, and only stopped a couple of thousand years ago, what’s the guarantee that they won’t resume in the future? Well, the short answer is: there isn’t one. But reassuringly, volcanism in Victoria seems to only occur cyclically every 25000 years or so. So if the volcanoes were to return, it definitely wouldn’t be our (or even our great-great-grandchildren’s) problem.
The Newer Volcanics Province has shaped Victoria in uncountable ways: literally in the formation of our landscape, historically in the bluestone of our buildings, and culturally in the Aboriginal mythos. So the next time you visit an aboriginal cultural centre, or any of Melbourne’s historical sites or even if you decide to take a break from the city to explore the surrounding countryside, keep on the lookout for these links to Victoria’s past.