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Wellington Caves

Wellington, New South Wales

 

Visit Wellington Caves Official Website

Wellington Caves are located just off the Great Western (Mitchell) Highway 8 km south of Wellington, approximately 360 km west of Sydney and 60 km southeast of Dubbo in New South Wales. The caves are developed in the Lower Devonian Garra Limestone (about 400 million years old). These limestones, formed largely of calcium carbonate, were deposited in a shallow sea by the accumulation of the shells and skeletons of a variety of marine organisms including corals, brachiopods, bivalves, gastropods, sponges, crinoids, foraminifera and ostracods. The limestones are dated as Lower Devonian using these fossils and another important group of phosphatic microfossils, conodonts (Druce, 1970).



Lower Devonian corals in the Cathedral Cave

The caves were discovered in the late 1820s and have been open to the public for guided tours since 1885. The first documentary evidence of the caves are pictures of Cathedral Cave (referred to as Mosman's Cave) painted by Augustus Earle around 1826/27 which also depict Aboriginal Wiradjuri people near the entrance to the cave. Cathedral Cave was further described by Hamilton Hume in 1828.

Plan of Wellington Caves (after Augee et al., 2008)

Three caves, the Cathedral Cave, the Phosphate Mine & Bone Cave and Gaden Cave are open to the public with guided tours averaging about 1 hour for each cave.

Cathedral Cave

This cave has been open for guided tours since 1885. The cave is developed mainly in massive limestone but the Cathedral Chamber which contains the impressive Alter and Pulpit formations is developed along a fault line between the massive limestone and folded thinly bedded limestones. The Cathedral Cave is interpreted as a multiphase cave with largely non-fluvial origins and its large cavities are characteristic of excavation by convection currents in rising waters (Osborne, 2007).

Survey plan of Cathedral Cave, Wellington Caves

The Alter & Pulpit, Cathedral Cave

Formations in Cathedral Chamber, Cathedral Cave (note bedded limestone)

Folded bedded limestone, Cathedral Cave.

Phosphate Mine & Bone Cave

Survey plan of the Phosphate Mine and Bone Cave, Wellington.

Phosphate was mined at the Wellington Caves complex during World War I between 1914 and 1918 but relatively little phosphate (about 6,000 tons) was produced. The origin of the phosphate at Wellington is not clear but multiple sources from bone and bat guano seem most probable, with bat guano being the predominant source (Osborne, 2001).

Phosphate Mine tunnel at Wellington Caves.

Layer of phosphate mined at Wellington Caves.

Bone Cave, which forms part of the Phosphate Mine complex, and other caves at Wellington are historically and scientifically significant as the site of the first known marsupial fossils in Australia and one of the most prolific fossil marsupial sites. Extremely important fossil marsupials, most of which were found in the Bone Cave of the Phosphate Mine, place Wellington Caves as one of the most important Pleistocene fossil sites globally.

Part of the bone bed deposits at Bone Cave, Wellington Caves (bones are white).

Wellington Caves is the type locality for the ancient giant Marsupial Diprotodon originally named from skeletons found in the caves around 1830.  The giant marsupials found at Wellington form part of the now extinct Australian Pleistocene megafauna that comprised a vast array of land mammals, reptiles and birds with body masses of 45 to more than 100 kilograms. This megafauna became extinct at about 46,400 years ago (Roberts et al., 2001). The cause of this mass extinction is still hotly debated with major climate change or anthropologically driven extinction being the main contenders.  Recent work indicates that humans were the primary cause of this dramatic loss of the Australia megafauna (van der Kaars et al., 2017).

Reconstruction of the largest ever known marsupial Diprotodon which weighed in at more than 3 tonnes.

Gaden Cave

Survey plan of Gaden Cave, Wellington (after Augee et al., 2008).

Gaden cave is a small cave discovered in 1902. It is a reasonably well decorated cave and noted for cave coral that occurs in Cave Coral Chamber. It's other feature of note is C02 rich foul air in the lower level C02 pit where measurements of C02 levels were recorded at 13.5% by Fraser (1958) which then prompted further studies at Gaden to investigate air quality for tourist caves (Osborne, 1981).

Cave coral in Cave Coral Chamber, Gaden Cave

Field of stalactites in Gaden Cave.

Stalactites and a column in Gaden Cave.

Stalactites and curtains in Gaden Cave.

References

Augee, M., George, C. and Welch, B. 2008. Wellington Caves. Wellington, Wellington Caves Fossils Studies Centre, 33pp.

Druce, E.C. 1971. Conodonts from the Garra Formation (Lower Devonian), New South Wales. Aust. Bur. Miner. Resour., Geol. Geophys., Bull. 116, 29-52.

Osborne, R.A.L., 1981: Towards an air quality standard for tourist caves: Studies of carbon dioxide enriched atmospheres in Gaden-Coral Cave, Wellington Caves, N.S.W. Helictite 19 (2), 48-56.

Osborne, R.A.L. 2001. Karst Geology of Wellington Caves: a review. Helictite 37 (1), 3-12.

Osborne, R.A.L. 2007. Cathedral Cave, Wellington Caves, New South Wales, Australia. A multiphase, non-fluvial cave. Earth Surface Processes and Landforms 32, 2075–2103.

Van der Kaars, S. et al. 2017. Humans rather than climate the primary cause of Pleistocene megafaunal extinction in Australia. Nature Communications 8, 14142, doi: 10.1038/ncomms14142 (2017).

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