The second largest is Old Alluvium, which is consisted of three pedoderm components, including Meander Plain (labelled as 1), Backplain (labelled as 2) and an unknown pedoderm (labelled as 3).
Conversely, intermediate-small K (0.2%-0.6%), characterised the Old Alluvium (Backplain) and Gin Gin Hills (Crests and Slopes), whereas intermediate K (0.6%-1.0%) defined the Old Alluvium (Meander Plain) and non-mapped areas in the Warren area.
Conversely, intermediate-small [EC.sub.a] (25-50 mS/m) characterised the Old Alluvium (Meander Plain), the Gin Gin Hills (Crests and Slopes) in the Trangie area and associated with Trangie Cowal and Contemporary Macquarie in the Warren area.
In terms of the [gamma]-ray data, the Mitchell class of the Meander Plain has a small clay activity (i.e.
In the south and west, the Old Alluvium pedoderm has various components: meander plain, backplain, and infilled channels.
The larger silt content indicates sediments were deposited under a lower energy regime than the Old Alluvium meander plain. The Macquarie class, which defines the Macquarie pedoderm, has minimal profile development, is characterised by considerable fine sand and silt fractions (i.e.
In brief, the coarser sediments associated with the Old Alluvium meander plain in the west are characterised by intermediate-small [[sigma].sub.a] (50-100 mS/m).
In the west, and with respect to the EM38h, the coarse sediments of the Old Alluvium meander plain are characterised by intermediate-small [[sigma].sub.a] (65-75 mS/m).
This may represent the location of a palaeochannel among the generally clayier part of the regolith associated with the Old Alluvium meander plain. To the east the EM34 decreases gradually across the Trangie Cowal to very small readings that are associated with the sediments of the Contemporary Macquarie River pedoderm.
Various components of the Old Alluvium pedoderm, including the meander plain and infilled channels, are apparent.
The modelling also indicates where the Old Alluvium meander plain is juxtaposed with the Old Alluvium backplain.
Nevertheless, the intermittent nature of the modelled root-zone [sigma] represents the sharp transition often observed within the Old Alluvium pedoderm: from the clay-rich soil types of the meander plain and the sandier soil of the backplain (McKenzie 1992).