UIS Commission on Karst Hydrogeology and Speleogenesis
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Karstbase Bibliography Database

Martini, Jacques E.J.; Grimes, Ken G.
Epikarstic maze cave development: bullita cave system, judbarra / gregory karst, tropical australia
Helictite
2012
41
37
66

 In the monsoon tropics of northern Australia, Bullita Cave is the largest (120 km) of a group of extensive, horizontal, joint-controlled, dense network maze caves which are epikarst systems lying at shallow depth beneath a welldeveloped karrenfield. The Judbarra / Gregory Karst and its caves are restricted to the outcrop belt of a thin bed of sub-horizontal, thinly interbedded dolostone and calcitic limestone – the Supplejack Dolostone Member of the Proterozoic Skull Creek Formation. Karst is further restricted to those parts of the Supplejack that have escaped a secondary dolomitisation event. The karrenfield and underlying cave system are intimately related and have developed in step as the Supplejack surface was exposed by slope retreat. Both show a lateral zonation of development grading from youth to old age. Small cave passages originate under the recently exposed surface, and the older passages at the trailing edge become unroofed or destroyed by ceiling breakdown as the, by then deeply-incised, karrenfield breaks up into isolated ruiniform blocks and pinnacles and eventually a low structural pavement. Vertical development of the cave has been generally restricted to the epikarst zone by a 3 m bed of impermeable and incompetent shale beneath the Supplejack which first perched the watertable, forming incipient phreatic passages above it, and later was eroded by vadose flow to form an extensive horizontal system of passages 10-20 m below the karren surface. Some lower cave levels in underlying dolostone occur adjacent to recently incised surface gorges. Speleogenesis is also influenced by the rapid, diffuse, vertical inflow of storm water through the karrenfield, and by ponding of the still-aggressive water within the cave during the wet season – dammed up by "levees" of sediment and rubble that accumulate beneath the degraded trailing edge of the karrenfield. The soil, and much biological activity, is not at the bare karren surface, but down on the cave floors, which aids epikarstic solution at depth rather than on the surface. While earlier hypogenic, or at least confined, speleogenic activity is possible in the region, there is no evidence of this having contributed to the known maze cave systems. The age of the cave system appears to be no older than Pleistocene. Details of the speleogenetic process, its age, the distinctive nature of the cave systems and comparisons with other areas in the world are discussed.

Tropical monsoon karst, network maze caves, epikarst, karren
Martini, Jacques E.J.; Grimes, Ken G., 2012, Epikarstic maze cave development: bullita cave system, judbarra / gregory karst, tropical australia , Helictite , 37 - 66 http://helictite.caves.org.au/abstracts4.html#41.00.005, PDF