Mallee (biogeographic Region) - Geography and Geology

Geography and Geology

The Mallee region has a complex shape with tortuous boundaries, but may be roughly approximated as the triangular area south of a line from Bruce Rock to Eyre, but not within 40 kilometres (25 mi) of the south coast, except at its eastern limits. It has an area of about 79000 square kilometres (31000 mi²), making it about a quarter of the South West Botanic Province, 3% of the state, and 1% of Australia. It is bounded to the south by the Esperance Plains region; to the west and northwest by the Avon Wheatbelt region; and to the east by the Coolgardie region.

There are a number of small towns in the west of the region, where wheat is grown. These include Gnowangerup, Lake Grace, Newdegate, Kondinin and Hyden. Also of note is the tourist attraction Wave Rock. Further east, the area is virtually uninhabited, except for Lake King, and a few small towns along the road from Norseman to Esperance, such as Grass Patch and Salmon Gums.

Most soil is sand over clay, overlying Archean and Proterozoic granite of the Yilgarn Craton. At the eastern limits there is some calcareous soil overlying Eocene limestone. The region has a low, gently undulating topography, with somewhat occluded drainage, resulting in a series of playa lakes.