The Lava That Left a Thousand Volcanoes: Queensland's McBride Volcanic Province

North Queensland's McBride Volcanic Province contains more than 150 eruption points, scattered across 5,000 square kilometres of savannah. The youngest of them erupted only 13,000 years ago—a geological blink. These are Australia's last active volcanoes, and they have not finished.

A Province of Cones

The McBride field lies west of Cairns, between the Great Dividing Range and the Gulf country. Unlike the towering stratovolcanoes of the Pacific Ring of Fire, this is a monogenetic field: each vent erupted once, then died. The result is a landscape dotted with scoria cones, lava shields, and maar craters, none more than a few hundred metres high.

Walking among them feels like trespassing on fresh ground. The cones are unweathered, their slopes still covered in loose scoria. The lava flows are dark and rough, with surfaces that crunch underfoot like broken glass. Kinrara Crater, one of the youngest, is a 300-metre-wide maar—a steam explosion crater formed when rising magma met groundwater. Its floor is a shallow lake, its rim a ring of ash and ejected blocks of granite ripped from the basement below.

The Lava Tubes of Undara

The province's most famous feature is the Undara lava tube system. Twenty-three million years ago, a massive flow of basalt erupted from a single vent and travelled more than 150 kilometres down an ancient river valley. As the surface of the flow cooled and solidified, the molten interior continued moving, draining away to leave hollow tunnels behind.

Some of these tunnels are more than a kilometre long and thirty metres wide. Their roofs collapsed in places, creating skylights that let in trees and vines. The tubes became refuges for wildlife and, later, for people. Aboriginal stories from the Ewamian people describe the formation of Undara as a giant ancestral snake that burrowed through the earth, its passage leaving the tunnels behind.

The tubes preserve a record of the eruption's dynamics: flow marks on the walls, stalactites of remelted basalt hanging from the ceilings, and smooth floors where the last trickle of lava solidified.

The Youngest Eruptions

Radiocarbon dating of charcoal beneath ash layers has pinned the most recent eruptions to the terminal Pleistocene. At Hill Paddock, a scoria cone east of Undara, the lava flow is so fresh that it has not yet developed soil. Eucalypt saplings root directly into cracks in the basalt.

The timing is significant. These volcanoes were active while humans were already living in Australia. The Ewamian people would have seen fire fountains lighting the night sky, felt the ground shake, and watched lava creep across the grass. Some oral traditions may preserve these events.

The volcanoes of the McBride field are not relics of a deep past. They are dormant, not extinct.

A Future in Asleep

The province sits above a mantle hotspot, a plume of hot rock rising from deep within the Earth. The same plume that built the McBride field is still there. Geodetic measurements show that the region is slowly uplifting, and seismic tomography reveals a low-velocity zone in the mantle beneath—the signature of partial melt.

Australia's most recent volcanic eruption occurred in 1445 at Mount Gambier in South Australia, but the McBride field is the continent's most active volcanic province by volume and frequency. It has produced eruptions every 10,000 to 20,000 years for the past 9 million years. By that clock, another eruption is overdue.

When it comes, it will not be catastrophic. Monogenetic eruptions are brief and localised, producing lava flows and ash fall that affect only a few square kilometres. But for the first time in human history, Australians will have a front-row seat to the continent's volcanic rebirth.