Latitude -33.987637, Longitude 150.110407
Located approximately 50 kilometres south east of Oberon
Sources: Field Geology of New South Wales, Branagan & Packham Principles of Physical Geology, Thomas Nelson & Sons, London, A. Holmes Layers of Time: The Blue Mountains and their Geology, NSW Dept of Mineral Resources, J.Pickett, J.Alder.
Kanangra Walls is a spectacular location with breath taking views over towering cliffs, tree clothed hillsides, cut-back valleys and even a beautiful waterfall. Walking tracks lace the area and you can walk to the base of Kalang Falls or out onto the plateau.
An unconformity is a buried erosion surface separating two rock masses or strata of different ages, indicating that sediment deposition was not continuous. In general, the older layer was exposed to erosion for an interval of time before deposition of the younger, but the term is used to describe any break in the sedimentary geologic record.
The rocks above an unconformity are younger than the rocks beneath (unless the sequence has been overturned). An unconformity represents time during which no sediments were preserved in a region. The local record for that time interval is missing and geologists must use other clues to discover that part of the geologic history of that area. The interval of geologic time not represented is called a hiatus.
In the image you can clearly see the unconformity at the base of Kanangra Walls where the strata changes from flat lying Permian Shoalhaven Group Sandstone and conglomerate on top and the underlying west-dipping Late Devonian Lambie Group quartzitic sandstones and red beds.
This unconformity represents the very edge of the large system known as the Sydney Basin. Above the unconformity lie more or less flat rocks of the Sydney Basin. These rocks stretch from here to the coast, south to Kiama. To the north they grade gradually into the New England Fold Belt somewhere in the vicinity of Scone. The rocks exposed here are the very beginning of the Sydney Basin, dating back to the Permian Era, some 270 million years ago (mya). Immediately below the unconformity, the rocks are of Late Devonian Age, some 400mya. Thus this unconformity represents a gap in the rock record of some 100 million years. In that time, the older sediments were buried, lithified (turned to stone), metamorphosed, tilted and uplifted and finally eroded to the surface that had the Permian and later Triassic sediments deposited on them. These in turn, have been lithified, uplifted and eroded in processes that are continuing today.
Take the Plateau Walk, a moderate grade one hour stroll which passes near the Dance Floor Cave. The Permian beds and the underlying Devonian Beds can be examined with ease. The Permian succession is compressed here. The course basal conglomerate (Megalong Conglomerate) is overlain by sandy shaly beds. Illawarra Coal Measures containing plant fossils, occur near the Dance Floor Cave and south around the cliff line where thin carbonaceous shale grades laterally into coal.
From the walls, extensive views in all directions enable the regional geology and landscape to be studied in detail. Note the dip of the plateau surface south-east towards the Kowmung River. To the south, the basalt cap of Mount Colong rises above the general surface. Far to the south the high country of the Goulburn region is visible. To the northeast beyond Cloudmaker, Coxs Valley and the Katoomba. If you take the track down the spur to Kalang Waterfall you will observe the process of weathering called valley cut back which has been achieved by the creek over millions of years. Also observe the pillars of sandstone, not unlike the Three Sisters rock formations, located on the opposite wall of the canyon. This is a sample of weathering of the rock via the joints in the sandstone. As water seeps into the outermost joints, the rock eventually weakens and drops off leaving the core pillar standing.
Access to Kanangra Walls is available via both Jenolan Caves or Oberon. To get to Kanangra Walls via Jenolan Caves travel west from Sydney along the Great Western Highway and before you reach Lithgow take the turn off road to Jenolan Caves and Oberon. Alternately Oberon can be accessed via the Great Western Highway or Tablelands Way.
Note that the last section of the road into the Jenolan Valley is one way from 11.45am to 1.15pm every day. This allows coaches to enter Jenolan safely on the narrow road. Visitors can still leave Jenolan during these times - via the Oberon Road which is fully sealed. Travel past Jenolan Caves and where the road splits to Oberon or Kanangra walls turn left travel past the Boyd River until you reach another fork and turn left again and travel to the end of the track. Take care in this vicinity as the cliff face has a vertical drop of hundreds of metres.
There is no camping at Kanangra Walls itself. The designated car camping area is 6km away at Boyd River, where there are plenty of facilities.