Granite Country

Formed about 1500 million years ago, the granite outcrops in the northern section of the Eyre Peninsula are part of the vast Gawler Craton - a geological shield structure covering central Eyre Peninsula, the Gawler Ranges and large parts of outback South Australia. Geologists refer to the inselbergs in the area as belonging to the Hiltaba suite of rocks - basically orthoclase rich pink granites dating from Eyre Peninsula's Precambrian age.

Nearby the Gawler Ranges were formed as a result of volcanic action. Unlike the Gawler Ranges however, Eyre Peninsula's inselbergs were formed as Batholiths or granite domes some 7 kilometres below the earth's surface. Clearly much soil erosion has occurred during the past 1500 million years. Equally remarkably, Pildappa Rock and many other Australian inselbergs exhibit very slow rates of weathering - with numerous studies indicating exposed granite surfaces eroding at rates below 50 centimetres per million years.

Geologists believe the process of the unique wave form or "flare" structure common to a number of granite outcrops in the area formation typically involves water runoff seeping into the soil at the base of granite rock faces. Over time, water and permanently moist soil conditions act together to chemically weather away highly reactive granite minerals such as orthoclase and mica. All this can take place at depths of up to 30 metres below the surface. In the case of Pildappa Rock, for example, soil levels have also gradually eroded away thereby exposing the prominent flare structure that we can see today.

Typical inselberg landforms can also be seen. Decaying granite sheet structures, minor tafoni forms, and "water grooves" known as rillen can all be found. Gnamma waterholes are often to be found at the top of the larger granite outcrops. Prior to European settlement gnamma rockholes were the only permanent source of water to be found in this part of Eyre Peninsula. For the local Kukatha tribe of aborigines such rockholes were an essential survival resource in a characteristically dry and arid environment. Early European settlers also recognised the value of such waterholes. At Pildappa pioneering farmers even constructed dam walls at the top of the rock in order to increase the rainfall catchment area of gnamma rockholes.




Pildappa Rock

Pildappa Rock
A unique pink inselberg located 15 kilometres northeast of Minnipa on the Eyre Peninsula. Situated in South Australia's granite country, locals proudly proclaim Pildappa to rival the more famous "Wave Rock" - a sandstone wave form located in Hyden, Western Australia. Below Pildappa Rock visitors will find an extensive system of man made gutters. These gutters were constructed in 1928 and designed to channel water runoff into a huge underground water tank on the northern side of Pildappa Rock.

Corrobinnie Hill

Corrobinnie Hill
A small conservation park preserves the ancient granite dome known as Corrobinnie Hill. Over the millennia, the granite has weathered into an amazing array of boulders and caves. From the top of Corrobinnie Hill there are sweeping 360 degree views of the surrounding farming country and granite outcrops. Access is stictly limited to 4WD, from Wudinna in the south or the Buckleboo Stock Route in the north.

Murphys Haystacks

Murphys Haystacks
The most southerly outcrop in the Gawler Ranges granite belt, Murphy's Haystracks is located approximately 40km south of Streaky Bay. The term "Haystacks" is something of a misnomer. These haystacks have nothing to do with farming and are in fact very fine examples of weathered granite inselberg structures including boulders and pillars. Upon entering the viewing area a unique and magnificent Tafoni structure can be seen towering above the walkway.

Elsewhere within the viewing area a variety of wave forms and flared rock structures can be seen. These are indicative of ancient physical and chemical weathering processes occuring when soil levels were several metres higher than now. These inselbergs are exemplified by finely sculpted pink granite forms that are often encrusted with lichen growths. Located near to the entrance of Murphys Haystacks is a picnic area with toilet facilities.

Ucontitchie Hill

Ucontitchie Hill
Located 32 km south of Wudinna township, Ucontitchie Hill is a domed granite formation rising to a height of 37 metres above the surrounding plain. As an Inselberg structure it is of international geological significance and exhibits many well developed and well defined structures and forms that are a result of chemical weathering processes. Around the base of the hill can be seen unique wave structures indicating previous levels of long since eroded soils. As you rise to the peak of Ucontitchie Hill you can observe vast slab like structures and fascinating sheets and boulders of granite that have been internally eroded into features known as Tafoni.

Polda Rock

Polda Rock
Located within an attractive reserve, Polda Rock was originally used as the catchment for the town of Wudinna's water supply. Much of the original infrastructure erected to catch water flowing off the rock during rain, including a hand constructed stone channel, and a reservoir remain in use. A popular reserve for short walks, bird watching and picnics.

Waddikee Rock

Waddikee Rock
Located adjacent to Eyre Highway at Koongawa, east of Wudinna, Waddikee Rock is a small exposed granite dome that provides excellent views of the surrounding landscape. A monument to John Charles Drake, who was speared by natives whilst travelling through the area, is located at the base of the rock.

Mt Wudinna

Mt Wudinna
Located within the Mt Wudinna Recreation Reserve, Mount Wudinna is Australia's second largest monolith after Mount Augustus. It is located 12 kilometres north-east of the township of Wudinna. Mt Wudinna rises 80 metres above the surrounding farmland. On the way to Mt Wundinna, just past Polda Rock, Little Mt Wudinna and Cottage Loaf Rock can be seen on the left and a working granite quarry on the right. Mount Wudinna, like many of the bare granite hills in the district, is encompassed by low stone walls to catch and divert run off water. The site is listed on the South Australian Heritage Register.

Tcharkuldu Rock

Tcharkuldu Rock
Located 6 km east of Minnipa, the Tcharkuldu Rock granite outcrop boasts numerous large granite boulders and tafoni which makes it a unique outcrop from others in the district. Tafoni are internally eroded rocks, which have resulted in cave like formations. A family of Euros is also said to live permanently at the site.

Yarwondutta Rock

Yarwondutta Rock
Located 4 km north of the township of Minnipa on the way to the Gawler Ranges. Yarwondutta Rock is a most interesting water catchment and reservoir area, and is located on the property of the Minnipa Agricultural Centre. The latter is a dryland farming research facility and centre of excellence.

Minnipa Hill

Minnipa Hill
Located 1.7 km north of Yarwondutta Rock, Minnipa Hill is the site of a radio relay tower. The recreation reserve which contains the hill offers views across the surrounding countryside.

Turtle Rock

Turtle Rock
Located on the main tourist drive to Mt Wudinna, Turtle Rock provides a great opportunity for photographers, however it cannot be climbed as it is on private property.

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