From Lava to Laneways: Victoria’s Igneous Rocks
Walk through Melbourne’s laneways or past its historic bluestone buildings, and you’re seeing the legacy of volcanic fire beneath your feet. Victoria’s Western Volcanic Plains — one of the largest volcanic regions on Earth — stretch from Melbourne’s west all the way to South Australia. The basalt and bluestone from these lava flows have literally built the foundations of the city.
How Igneous Rocks Form
Igneous rocks are created when molten material (magma or lava) cools and solidifies.
Intrusive (plutonic) rocks, like granite, form slowly beneath the Earth’s surface, growing large crystals.
Extrusive (volcanic) rocks, like basalt and pumice, form when lava cools quickly at or near the surface, creating fine-grained or porous textures.
Victoria’s story is dominated by extrusive volcanic rocks: thick basalt lava flows that blanketed the plains, sculpted the land, and provided a resource that built Melbourne.
Igneous Rocks in Everyday Victorian Life
Bluestone buildings: Many of Melbourne’s 19th-century buildings, bridges, and drains are built from local basalt, commonly called “bluestone.”
Laneways and paving: The cobblestones in Melbourne’s CBD laneways are cut from basalt.
Modern uses: Basalt remains important for road base, railway ballast, and concrete aggregate.
Igneous Rocks and Resources
Beyond construction, igneous systems also provide critical resources:
Nickel, copper, and PGEs (platinum group elements): Found in large igneous intrusions.
Lithium and rare earths: Sourced from igneous pegmatites like Greenbushes in WA.
Industrial stone: Basalt, pumice, and granite continue to be quarried for local and export markets.
These highlight how igneous activity underpins not only landscapes but also modern industries and renewable energy technologies.
Why It Matters for Students
Exploring igneous rocks helps students connect the science with the world around them:
Why Victoria is home to one of the world’s largest volcanic plains.
How volcanic rocks built Melbourne’s laneways and infrastructure.
How igneous systems generate minerals critical for technology and sustainability.
✅ Curriculum Link: Earth Science – Rock Cycle (VC2S8U11)
Students explain how igneous rocks form and how their properties determine their uses and influence mining methods.
