Cliefden Caves

Ruin of "Cliefden Springs" house located on Island Flat, Cliefden NSW Australia

The Cliefden Caves Geoheritage Site is multifaceted, containing internationally significant Ordovician fossil localities, limestone caves of national significance, a warm spring and tufa dams of state significance and the historically significant site where limestone was first discovered in inland Australia. It has been ranked among the 70 most significant fossil sites in Australia by the Australian Heritage Council (2012^[1]) and as the thirteenth most significant limestone cave site in Australia by Davey.^[2] The site was nominated to the Register of the National Estate by the Geological Society of Australia in the late 1970s and registered in 1987 (Place ID 958, File # 1/07/261/004).^[3]

History

The outcrop of Cliefden Caves Limestone at the junction of Limestone Creek and the Belubula River was first discovered during the explorations of surveyor George Evans on 24 May 1815, only 2 years after the crossing of the Blue Mountains. A cave was recorded on the southern bank of the Belubula River as early as 1832 (Lands Department, 1832) and map from 1883 shows the location of Bushrangers Cave, The Murder Caves and Immense Cave, apparently Main Cliefden Cave (Lands Department, 1883). In 1908, Oliver Trickett (Trickett, 1909), Superintendent of Caves, reported on Cliefden Caves “in connection with their protection on the proposed resumption of the Cliefden Estate”, examined Main Cave and concluded that it was “well worth preserving”. Anderson (1924) similarly concluded that the caves were well worth preserving.

Fossil Hill, Cliefden NSW Australia

The Site has been ranked among the 70 most significant fossil sites in Australia by the Australian Heritage Council^[4] and as the thirteenth most significant limestone cave site in Australia by Davey.^[2]

The first land grants, of 2460 acres each at Cliefden Springs and Cliefden, were taken up by brothers F.J. and W.M. Rothery in 1832.^[3] The barn at the homestead sports bullet holes which occurred when the Rothery family was held up by Ben Hall’s gang in the 1860s.^[5]

In the 1950's Stevens^[6] was able to show the limestone was of Ordovician age, the first recording of limestone from this period in New South Wales. Geologists around the world regard it as a superb example of an Ordovician island faunal assemblage^[7]

The area is particularly rich in fossil material and has become known as one of the best documented Late Ordovician successions in Australia. The book "Australia's fossil heritage" states that "The site is unusual because of the well exposed, diverse faunas showing the progression from near-shore to deep water marine environments. It contains abundant examples of some of the earliest shell beds in the geological record and the earliest rugose corals known. More than 180 species have been recorded from the Cliefden Caves Limestone Group and the Malongulli Formation. The Cliefden Caves - Belubula River Valley sites contain the best exposures of Late Ordovician island marine invertebrate fossil assemblages in Australia. The sites include the type localities for over 100 species."

Scientific Value

The NSW National Parks and Wildlife Service states that "...lesser known karst environments can also contain extensive and well-developed karst features, like those at Cliefden and Walli. In some cases these features are of regional and state significance, highlighting the importance of all karst environments, whether publicly or privately managed." The report also states that "Thermal springs ... are rare in NSW and, besides Wee Jasper, occur only at Cliefden and Yarrangobilly caves. The report also describes Cliefden Caves as an important karst site.^[8]

With more than one hundred recorded caves,^[9][10] Cliefden Caves is one of the most cavernous limestone areas in New South Wales. The caves at Cliefden have a network pattern guided by geological structure. While they are located close to the Belubula River, there is no evidence that streams or the river have ever flowed through the caves. The caves show evidence of solution by rising groundwater possibly related to the adjacent thermal spring. One of the most significant caves at Cliefden is Taplow Maze Cave with a network of passages over 3 km long (survey in progress by the Sydney University Speleological Society). Compared with other scientifically studied caves in central-western NSW (Walli, Borenore, Stuart Town & Wellington), Cliefden Caves contain an abundance and great diversity of speleothems (stalagmites & stalactite etc.) most in very good condition, including significant deposits of helictites, rare blue stalactites ^[11] known from only one other locality in NSW, and very rare polyhedral, monocrystalline stalactites and columns (Osborne, 1978).

Some of the sediments at Cliefden Caves, particularly the laminated muds are quite unlike those other NSW caves. They contain unusual minerals and an important record of past environments.^[10] Deposits of fossil bones occur in several caves, but have been little studied. Molnar et al. identified a Ghost Bat tooth from Cliefden making Cliefden Caves one of the most southerly locations for this genus, now restricted to warmer parts of Australia with a minimum January temperature above 20 degrees.^[12]

Unlike the fossil sites, there has been little recent scientific research on Cliefden Caves, mainly due to a shortage funding and of cave science specialists. The caves have great research potential, particularly in relation to the determination of past climates and hydrological conditions.

The construction of a dam at the Needles Gap site on the Belubula River will completely flood most of the caves, destroying their heritage value and preventing future study. Other dam sites called Cranky Rock and Cranky Rock Alternate also affect the Cliefden area.

Davys Creek Tufa Dams

Active tufa dams in creeks are uncommon in NSW and have received little study. The tufa dams in Davys Creek are the most studied in the State. Drysdale et al.^[13] showed that deposition at the tufa dams was dependent on weather conditions, making tufa dams a likely source of information about past climatic conditions. Carthew and Drysdale ^[14] demonstrated that it was possible to use information from the tufa deposits to construct a history of stream development in Daveys Creek. Both these papers illustrate the scientific potential of the geoheritage features at Cliefden Caves.

Thermal Spring

A thermal spring is located on the Belubula River near the caves. It is only one of three thermal springs associated with karst in NSW.^[15] It was first recorded by Wilkinson in 1892,^[16] and an analysis of the water appears in a report by Oliver Trickett in 1908.^[17] Warm springs rising from Palaeozoic rock (as opposed to those from the Australian Basin) are rare in NSW with only three documented, all in karst areas. These are the Cliefden Warm Spring, a warm spring at Wee Jasper and the warm spring at Yarrangobilly Caves. There has been little study of warm springs in NSW.Despite assertions to the contrary, the Cliefden Thermal Spring is not on private property and is accessed via a public road.

Threat from Dam

Proposals for water storages on the Belubula River date back more than half a century. Sites exist between Carcoar and Canowindra and several of these would adversely affect Cliefden Caves and surrounding areas. The site most mentioned is at The Needles, where the river has cut a narrow gap through a resistant zone of conglomerates, quartzite and sandstones. Any dam at this site, only 2.5 km from the caves, would inundate most of the known caves, the thermal spring, most of the fossil sites, and large areas of the rich alluvial agricultural flats (see map at http://www.savecliefdencaves.org.au/dam_proposals).

There is at present no statutory protection of any form afforded to these caves. Fortunately, the present landowners maintain an active interest in them and are well aware of their value and restrict access.

References