Karst

Karst, Ital. Carso, Slovenian Kras, limestone plateau, W Slovenia, N of Istria and extending c.50 mi (80 km) SE from the lower Isonzo (Soča) valley between the Bay of Trieste and the Julian Alps. It is characterized by deep gullies, caves, sinkholes, and underground drainage—all the result of carbonation-solution. The best-known caves are at Postojna. The barren nature of the plateau deters human settlement. Rough pasture or forest covers much of the surface, and there is little arable land. The term karst is used to describe any area where similar geological formations are found.

London Bridge is a limestone karst near Canberra, Australia that consists of a limestone arch hollowed out by the Molonglo River.

It was first discovered by the European explorers Captain Mark Currie, Brigadier Major John Ovens, Joseph Wild and accompanied by two nameless aboriginal guides in 1822. It was in danger of being flooded by the construction of the London Bridge Dam but owing to its limited catchment, the Australian Government constructed Googong Dam instead. London Bridge is inside a nature reserve and is thus now protected.

References

External links

• Photo and Records from the Register of the National Estate