13 Gey and brown (occasionally black, yellow or red) mottled texture contrast soils on Neogene sediments

These soils are found on the gently undulating plains, rises or low level plateaux underlain by Neogene sediments (generally sands, often ferruginised) which are generally unconsolidated but often have an indurated pan or layer on which the soils have developed.

The surface soil is generally dark with organic matter but light in texture (sandy loam) and between 10 to 25 cm in depth over a (generally) lighter coloured subsurface (A2) horizon (20 to 30 cm depth) of similar texture to the surface but containing less organic matter. The apedal subsurface horizon is often bleached and may contain buckshot (ferruginous or ferromanganiferous nodules) of up to 50% volume of the subsurface horizon. These horizons clearly contrast with a dark (black, dark grey or dark brown) strongly structured upper subsoil which then grades into a pale/red mottled lower subsoil which grades into weathered sediments or ferruginised sandstone at about 150 cm. The dark upper subsoil is a result of organo-clay translocation from above, coating the mottled soil aggregates or even replacing the mottle, and is a distinctive feature of soil development on this parent material.

Notable features include: the presence (or absence) of buckshot sitting on top of the subsoil, the sandy nature of the upper soil, occasional unbleached horizon which may be loose or weakly coherent, some sodicity of the lower subsoil, red and pale mottling of the subsoil, and the range of depth to parent material (60–150+ cm). The role of local climate, particularly rainfall, may influence soil development and such features as tiger mottles in weathered parent material are found further west in the CMA.		CLRA Soil Unit 13


Soil Sites
Site Code
Soil-landform unit
Component
ASC
FK
1:100 000 mapsheet
CLRA72
Mid slopeMelanic-vertic, Eutrophic, Black ChromosolDb2.31T7821 - Sorrento
Mid slopeBleached-sodic, Eutrophic, Grey ChromosolDy3.43T7821 - Sorrento
Mid slopeMottled, Mesotrophic, Brown ChromosolDy3.51T7521 - Corangamite
Lower slopeBleached-Mottled, Eutrophic, Brown ChromosolDb2.41T7521 - Corangamite
Upper slopeBleached-Mottled, Eutrophic, Black ChromosolDd2.42T7521- Corangamite
OTR492
Lower slopeEutrophic, Mottled-Subnatric, Brown SodosolDy3.41T7721 - Geelong
Mid slopeFerric, Mesotrphic, Brown ChromosolDy3.11T7721 - Geelong
OTR744
HillcrestMelanic, Mottled-Subnatric, Brown SodosolDy5.22T7621 - Colac
OTR783
Mid slopeMelanic, Dystrophic, Brown ChromosolDb1.42T7520 - Princetown
Upper slopeMelacic-Mottled (& Vertic), Eutrophic, Brown ChromosolDy3.32T7521 - Corangamite
159
CrestReticulate, Mesotrophic, Brown ChromosolDy3.42T7520 - Princetown
SW65
FlatReticulate, Mesotrophic, Brown DermosolDy3.11T7521 - Corangamite
SW66
CrestMelacic-Mottled, Eutrophic, Brown ChromosolDy3.21T7521 - Corangamite
Mid slopeBleaced-Mottled, Eutrophic, Brown ChromosolDb2.21T7521 - Corangamite
SW68
CrestBleached-Mottled, Eutrophic, Brown ChromosolDb2.41T7521 - Corangamite
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