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Geological Monuments

What is a Geological Monument?


Rawnsley Quartzite overlying red Bonney Sandstone, Rawnsley Bluff, Wilpena Pound.

Exposures or outcrops of rocks are numerous and diverse in much of South Australia, but, surprisingly, relatively few provide outstandingly significant scientific data.

The ones that do, however, constitute irreplaceable segments of earth history. They illustrate one or more geological features and/or processes that are not shown elsewhere or with such clarity. Some of these sites show features of such outstanding geological or geomorphological significance that they are considered by the community of earth scientists to be worthy of conservation, and are then designated as Geological Monuments; together they constitute the State’s Geological Heritage.

Sometimes, additional qualities such as aesthetic appeal, rarity and historical links may be present, in which case the monument is likely to be better known to, and more valued by, the public at large. Some may be well-known as landscape features and have an additional role in tourism and recreation. Typical places where these monuments occur are natural outcrops, river or coastal sections, disused quarries, road cuttings, and occasionally caves. They may be a single small outcrop, or a large landscape feature such as Wilpena Pound; they may be located on public or private land.

Unlike living systems, geological monument sites are not reproducible, and when damaged or destroyed are lost for ever. Consequently, the need exists to identify and protect a wide range of such sites. The importance of geological monuments is that they:

  • provide illustrations of geological features and processes that aid in the teaching of science at all educational levels and that are used, especially by the professional community of earth scientists, for research and reference.
  • preserve geological features that are representative, rare, or even unique to science in this State, Australia or internationally.
  • preserve geological features that are of aesthetic, educational or recreational value to the general public.

The Sugarloaf, Hallett Cove.
A monument may also include a type section - this is a location where a rock mapping unit is considered to be most typically exposed and is used as a reference point in understanding the mapping unit and identifying it elsewhere.Many familiar South Australian localities are designated geological monuments and the geological features of a few examples are given below:
  • Wilpena Pound: prominent geomorphological feature showing folding of sediments on a large scale; also a landscape and tourist item.
  • Hallett Cove: displays rocks from several different ages and their relationships; preserves glacial features discovered in 1877; also contains type sections of two units; extensively used for teaching.
  • Mount Gambier and Mount Schank: the youngest sites of Quaternary volcanism in South Australia.
  • Ediacara: fossils of among the oldest diverse and abundant marine fauna known to science, first discovered in 1946.
  • Arkaroola area: a wide range of unusual rock types and mineral occurrences; contains a number of type sections; also important for tourism, nature conservation, and research into mineralisation processes which have affinities to those at Olympic Dam.
  • Sellicks Beach and quarries at Highbury: these display evidence of Cainozoic faulting and sedimentation important in interpreting the history of uplift of the Mount Lofty Ranges, and potentially useful for understanding present-day earthquake activity and hazards; the Eden Fault at Highbury would not have been visible without intervention by man.
  • Dalhousie Springs: these wetlands are not only vital to the local fauna and flora, but are a window into understanding the groundwater characteristics and structural features of the Great Artesian Basin.
  • Southern Eyre Peninsula, and Redcliff Point, near Port Augusta: these are two localities with vastly contrasting coastal geology: the southern Eyre Peninsula is a geologically stable exposed coast dominated by ancient metamorphic rocks (among the oldest known in the state), highly resistant to marine erosion and forming the foundation of high cliffs; the more protected and slowly uplifting northern Spencer Gulf by contrast, shows Holocene sediments building out seawards with the type of sediment deposited closely tied to water depth and degree of tidal inundation.

Further Information

For further information on the Geological Monuments of South Australia contact:

Wayne Cowley
Geological Survey Branch
Primary Industries and Resources South Australia
GPO Box 1671, Adelaide, SA, 5001
(08) 8463 3076

Questions in writing may also be sent to the Geological Society of Australia:
Secretary, SA Division
Geological Society of Australia
P.O. Box 295
Kent Town, SA, 5071

Acknowledgements

The introductory portions of volumes 7 and 8 of the Geological Society’s Geological Monuments in South Australia reports were extensively drawn upon in compiling this article. Discussions with the members of the Geological Heritage Subcommittee has also led to improvements.