Geomorphology: Saline coastal flats: saline estuarine and littoral flats with extensive bare mud surfaces and slightly higher samphire flats; mangrove fringes occur along the seaward margin, and short sandy slopes, with outlying low sandy rises, occur at the landward margin; minor fixed dunes; dense, intricately branching pattern of shallow tidal inlets; slopes mainly less than 0.3%.
Land management: Parts of the system support variable littoral pastures which are moderately favoured by stock. Controlled stocking required to prevent vegetation degradation and soil scalding. Mangrove communities have high conservation value.
Image of tidal mudflats and mangrove lined creeks of the Carpentaria land system surrounding Derby town site. The width of this 2007 aerial photograph is about 12km. Photo: Landgate
Stylised plan diagram showing arrangement of land units for the Carpentaria land system (for the west Kimberley survey) (numbers on diagram represent land units in table below)
Table of Carpentaria land system – land units, WKY survey area. * Numbers in brackets refer to soil family or vegetation community/alliance in ‘General report on lands of the West Kimberley area, WA’ (Speck et al. 1970); + Pasture types described in Appendix 1; Note: Proportions and occurrence of pasture types within land units are subject to change over time due to invasion by native and introduced species, seasonal conditions, fire frequency and grazing management.
Unit
Approx.
area
(%)
Landforms
Soils*
Vegetation*
Pasture type+
1
8
Inner slopes: concave, up to 1% and 230m long; lightly firmed sandy surfaces.
Yellowish sandy soils, commonly mottled and showing saline influence: Tableland family (5).
Thickets of Melaleuca spp. with variable ground storeys. Melaleuca alsophila alliance (35a, 35b).
RAPP 50%
LITP 50%
2
2
Drainage mouths:up to 3.2km wide, traversed by numerous runnels and channels 1–50m wide and up to 1m deep; vegetated sandy rises up to 0.6m high with intervening bare sealed surfaces.
Variable soil complex mainly yellowish, sandy soils: Tableland family (5); and loamy alluvial soils: Robinson family (21). Both exhibiting local saline influence.
As for unit 1.
RAPP 50%
LITP 50%
3
19
Samphire flats: up to 4.8km in extent, with slopes less than 0.3%; margins up to 0.2m above mud flats.
Brownish and greyish, calcareous, saline loams (26).
Halophytic shrubland. Samphire community (66).
SMPP 60%
LITP 40%
4
40
Mud flats: up to 6.4km wide with slopes less than 0.3%; sealed, cracking surfaces with microrelief.
Dark saline muds (28).
Bare mud.
XXNP
5
2
Dunes: linear, up to 3.2km long and 6m high, with narrow, irregular crests; flanks slope up to 5%.
Sandy commonly calcareous beach dunes (29).
Spinifex longifolius and other perennial tussock grasses and forbs with an open shrub layer (Acacia spp.) and scattered trees. Beach-dune community (67).
Outer flats: up to 3.2km in extent; in shallow water or exposed at low tide.
Dark saline muds (28).
Dense mangrove communities, Medium-height (2 – 3 m) mangrove community (45) occupies the inner part of this zone and a taller community 3 – 8m high (44) occupies the outer or seawards margin.