6. Western Plains (WP)
6.1 Volcanic plains
Plains with well developed drainage represent the earlier Pliocene volcanic landscapes, from five million to two million years ago (mya), and are transitional to geomorphological unit 6.1.3. Examples of this landform can be seen in the region north-west of Cressy and south-east of Wallinduc, and drainage is well established and ephemeral wetlands are relatively few. These areas are characterised by very planar landscapes with thicker soil development. Regolith profiles on these old basaltic lavas have developed many metres of pallid kaolinitic clay, with ironstone at shallow depth. Associated soil types are predominantly black and brown sodic mottled texture contrast soils (Sodosols). Scattered Red Gum cover is characteristic, and the areas of this unit are charactteristically plateaus, with deep valleys incised at their margins. |