Geology and topography

• Geology
• Terrain

Geology

The north and east sections of the province are dominated by sandstone; the south is dominated by deep heavy grey and brown cracking clays.  The Australian Natural Resources Atlas (ANRA, 2002) has more detailed geological descriptions about the various vegetation bioregions composing the WCG province:

• Cape York Peninsula consists of complex geology dominated by the Torres Strait Volcanics in the north.  South of the region has deeply dissected sandstone plateaus and flat plains of colluvial and alluvial clays, silts, and sands.  West of the region contains extensive sand sheets. 
• Einasleigh Uplands consists of high ranges and plateau surfaces of palaeozoic sediments, granites, and basalts. The region generally has diverse geology ranging from mesozoic sandstones occurring as small plateaus, alluvium, permian granites palaeozoic sediments, acid volcanics and rugged ranges on folded sediments and igneous rocks.
• The Mitchell Grass Downs are characterised by undulating downs on shales and limestones.  The soils are predominantly deep heavy grey and brown cracking clays often with self-mulching and sometimes stony surfaces. The plains are interspersed with drainage lines.

Terrain

The Western Cape and Gulf has, on average, a low relief ratio, with a mean for the province of 0.013. High relief ratio areas are spread throughout the east of the province.  Stream segment slope values are also low, with higher values corresponding to areas with high relief ratio values.

The province is dominated by the erosional and valley bottom flatness index class both of which dominate different regions of the province.  A small proportion of the province contains ridge top flat areas, which occupy the borders between erosional and valley bottom flat areas.

Terrain

Methods

Province Terrain Map   State Terrain Map