Mount Augustus Geology and Geomorphology.

Mount Augustus (Burringurrah) at 1105 m AHD, is a prominent elongate inselberg, underlain dominantly by resistant sandstone of Middle Proterozoic age (1.6 billion years old). It is located midway between Meekatharra and Carnarvon in semi-arid Western Australia. The Mount Augustus Sandstone and overlying sediments were folded and tilted about 1 billion years ago, providing the template for the modern Mount Augustus. It is essentially a structural landform. Its shape broadly conforms to the underlying asymmetrical anticline, which has a steep northern limb and a gentler dipping southern limb. The anticline plunges at a shallow angle to the southeast. The mountain is the core of the original fold and it stands some 700 m above the surrounding Gascoyne planation surface. Other rock types present on Mount Augustus include metamorphic and igneous rocks, which preclude it from being termed a monolith. Weathering, fluvial erosion and sedimentation have modified the original bedrock structures. Fluted bedrock provides evidence of rapid runoff from bare bedrock surfaces. A joint system has influenced the orientation of a step-like sequence of numerous scarplets on slopes. The weathered rock is red, but the coloured rock is only a centimetre deep on most surfaces. The surrounding alluvial, gibber and sand plains shallowly bury the eroded bedrock plains of the Gascoyne planation surface. Former alluvial fills have been ferricreted in the lower reaches of some channels and are currently being eroded. Mount Augustus has often been compared with Ayers Rock, and unwarranted claims have been made that it is the biggest rock in the world and the world's biggest monolith. [ABSTRACT FROM AUTHOR]