Petrogale Cave, Madura Roadhouse, Dundas Shire, Western Australia, Australiai

Regional Level Types
Petrogale Cave	Cave
Madura Roadhouse	Community
Dundas Shire	Shire
Western Australia	State
Australia	Country

Petrogale is the genus name for rock wallaby.

The cave is 36 kilometres east of the Madura roadhouse on the edge of the scarp. It appears would be difficult to find, forming only a small sinkhole on the surface before opening out into a chamber further in.

The cave was discovered by Peter Bridge in a Western Australian Museum expedition in 1973. The new species archerite had been found at Murra-el-Evelyn Cave, but not in sufficient quantities to make a positive identification. A search was then undertaken for other caves which could contain the species. On the way back to Perth, the landrover was wrecked in a rollover, Bridge bemoaning the damage to his specimens.

At the surface it forms only a minor sinkhole, and there appears no easy access to the location. Once through the narrow sinkhole, it opens into a chamber with old calcite decorations. The mineralization was found at the far end of the cave, through several long chambers and tight clefts. Bats are wonderful creatures but keep a messy home. The species were formed from guano of the Chalinolobus morio bat, of which only a few were seen, but possibly more inhabit the cave seasonally. The floor of the cave was covered in dry guano dust, as any fresh material is devoured by coprophagic insects.

The walls show convoluted crusts and stalactites of the minerals. The stalactites are mainly composed of biphosphammite, with some other minerals (calcite and guanine), where they join the wall or ceiling. Some stalactites are composed mainly of aphthitalite.

Archerite was found in only a few samples as small tetragonal crystals to 2mm long, and buff to clear coloured crusts, associated with biphosphammite, aphthitalite and guanine.

Mundrabillaite is named after the pastoral station on which the caves are located, and was discovered during Peter Bridge's 1973 visit, but only studied and IMA approved in 1983. It comes as tiny crystals associated with archerite, bisphosphammite, aphthitalite, halite, syngenite, stercorite, newberyite, calcite, and an unknown phosphate. The crystals are colourless, with an earthy lustre, white streak, soft and fragile.

Other Regions, Features and Areas containing this locality

References