Sawn Rocks

The Organ Pipe Rock

Found in the northern section of the Mount Kaputar National Park these majestic rock colomns rise 40 metres above the Bobbiwaa Creek looking like a wall of giant organ pipes. Mount Kaputar is the remnants of an extinct volcano that was active about 18 million years ago. Sawn Rocks are the columnar basalt rock produced during the cooling of thick lava. Basalt is the most common rock on Earth’s surface. Specimens are black in color and weather to dark green or brown. Basalt is rich in iron and magnesium and is mainly composed of olivine, pyroxene, and plagioclase.

During the cooling of a thick lava flow, contractional joints or fractures form. If a flow cools relatively rapidly, significant contraction forces build up. While a flow can shrink in the vertical dimension without fracturing, it can’t easily accommodate shrinking in the horizontal direction unless cracks form. The extensive fracture network that develops results in the formation of columns. The topology of the lateral shapes of these columns can broadly be classed as a random cellular network.

These structures are predominantly hexagonal in cross-section, but polygons with three to twelve or more sides can be observed. The size of the columns depends loosely on the rate of cooling; very rapid cooling may result in very small columns, while slow cooling is more likely to produce large columns. Displaced colomns from the face of Swan Rocks may be seen in the creek bed and are mostly poligonal in shape.

From the car park at Sawn Rocks it is an easy walk along a 750 metre walkway with signs along the way to understand the facinating landscape. Benches along the way allow time to sit and rest and to take in the atmosphere. A raised walkway allows you to explore the gully without damaging the fauna below and then opens out to the viewing platform overlooking the pipes. It is here from noon to afternoon that the rocks are in the best light and produce the best images.

This whole area is a protected national park so “take nothing but photographs and leave nothing but footprints” leave your pets at home and don’t feed the local animals. Plan your trip and enjoy the natural wonder of this place.