Rock Solid – New South Wales Geologic Features

Carly Chabal, Intern, National Parks Association of NSW

Every year, millions of visitors flock to sites like Half Dome, the Grand Canyon, and Kilimanjaro, pull out their cameras, find the perfect lighting, adjust the focus, and—you guessed it—take a selfie. Jokes aside, all of these locations are home to unique plants and wildlife, but they wouldn’t be nearly as amazing without the spectacular landscape.

There’s something mesmerising about natural geologic wonders in a world that is becoming increasingly filled with concrete. One of the things that make Australia so lovely is its dramatic landscape. From the white sandy beaches of the Gold Coast to the towering Uluru, Australia is a geologic wonder. Here in New South Wales, we have access to an expansive karst environment, the wild Blue Mountains, towering coastal cliffs, one of only four glacial cirque lakes in mainland Australia, and the highest peak on the main continent.

When we think of environmental conservation, we think about protecting threatened and endangered species, restoring habitats, and switching to clean energy sources. Geology is often an overlooked aspect of conservation because it is, quite literally, in the background when we look at nature. Geology is seen as one of those things that has always been and always will be, so it’s harder for us to appreciate it. In the short age of humans, we haven’t seen any major geologic events happen, but that doesn’t mean all geology is static.

Why should we protect some rocks?

From an economic standpoint, geology provides resources for mining and tourism. Environmentally, geodiversity is the backbone of ecosystems. Each habitat has its own combination of rocks, minerals, landforms, soil, rivers, and erosional patterns that allow the surrounding flora, fauna, and biota survive1. For us, geology provides water storage and filtration, soil to farm, and energy to fuel our lives.


The boundaries of New South Wales encompass the southeastern section of the Great Artesian Basin, one of the world’s largest aquifers. This aquifer spreads below 12% of NSW’s land area and lies in permeable Mesozoic Era sandstones3. The basin recharges through exposed sandstone in the high elevation of the eastern mountains and drains through natural springs in the south. The Great Artesian Basin is Australia’s most valuable hydrologic resource, and most rural Australians rely on it for agricultural and personal use2. Mining and drilling companies are beginning to affect the aquifer through pollution and removing water faster than the recharge rate2.                  


Some of Australia’s most impressive geology can’t be seen unless you’re looking for it…underground! New South Wales is home to over 2,000 cave systems and 100 karst environments4. The cave systems in NSW such as the Abercrombie and Jenolan Caves span thousands of square kilometres below the surface. You may think of cave systems to be a great spot for some weekend spelunking, but cave systems provide unique habitats for species of bat, fungi, and insects, as well as information on climate change impact in the area4. Karst environments are sensitive to erosion because of their limestone composition, so they are easily affected by climate change.


The Blue Mountains are one of New South Wales’ most scenic destinations. From the outstanding Three Sisters formation to the greenish-blue haze of the eucalyptus, the Blue Mountains are a picture-perfect landscape worthy of a postcard home to grandma. However, geologically, the Blue Mountains aren’t even mountains at all. Their elevation comes from a period of uplift 170 million years ago that raised a sandstone and shale deposit into a high plateau5. The deep valleys and gorges are a result of erosion from rivers cutting downward through the rock. Shale is even easier to erode than sandstone, so once those layers wear away, the surrounding sandstone breaks away in large chunks leaving behind vertical cliffs5. This combination of uplift and erosion has created an illusion of a vast mountain range.


The conservation of biodiversity and geodiversity needs to go hand-in-hand. At the end of the day, most people will never be inspired to save some rocks and soil in the same way they would be for a koala. Geology is taken for granted, but these structures are beginning to feel the impact of human activity as well. Hopefully, we can begin to shift the conversation toward geological preservation and bring to light the immense importance of these features.


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