Tweed Shield Volcano and Caldera

Australia’s Gold Coast is full of incredible natural wonders, including the Tweed Shield Volcano and Caldera, which is the largest erosion caldera in the entirety of the southern hemisphere.

The volcano is now extinct, but the surrounding landscape still provides an incredible backdrop to explore if you’re in the area. You might have heard of the scenery under a different name – it’s also been dubbed Mount Warning Volcano, Tweed Volcano, and Tweed Caldera amongst others.

It has also been declared as a Landscape of National Significance by the National Landscape program, who has also given it the title of Australia’s Green Cauldron.

From these names alone, you can see just how magnificent the volcano and caldera is. Today, the valley carves down more than 1000 metres into the landscape and boasts a diameter of over 40 kilometres. This makes it even bigger than the world-famous Ngorongoro Crater in Tanzania.

So, you might be wondering what a caldera even is.

It’s actually a bowl-shaped depression that has been caused over many years by the collapse and erosion of a volcano.

The Tweed Shield Volcano and Caldera is the largest of its kind in the southern hemisphere and one of the most impressive calderas in the world, creating a jaw-dropping natural wonder that is a must-visit when you’re exploring the Gold Coast.

The Geology of the Caldera

For the past 20 million years, most of the material that has been pushed out of the volcano has eroded away, affecting the minor creeks and tributaries that wind their way across the valley floors.

The remaining landscape is still incredibly impressive, though. Thought to be the central magma plug, Mount Warning and a series of ring dykes that are made up of a harder rock than the rest of the landscape have resisted erosion and now dominate the valley, particularly around the township of Murwillumbah.

A lid of hard, basaltic rock has protected the rim around the western side of Mount Warning, which now soars skywards to around 1100 metres. These days, it is becoming commonly known by its Aboriginal name, Wollumbin.

The Tweed Shield Volcano and Caldera is a sight to behold, etching a hearty dose of ancient geological history into the picturesque surroundings of the Gold Coast. As well as exploring the immense beauty of the region, you can also learn about the fascinating geological formations that have taken place over the years to lead the landscape to look like the way it does today.