Victoria's Geomorphological Framework (VGF)
6.1 Volcanic plains
6.2 Sedimentary plains (Plains on unconsolidated (sedimentary) deposits
6.3 Hills and low hills (Mt Kinross, Greenvale, Mt Emu, Summerhill, Darraweit Guim)
The Victorian Western Plains are made up of low-lying undulating plains formed on both volcanic and sedimentary lithologies. The landscapes of this geomorphological unit are formed on some of the youngest rocks of Victoria. Soils on the Western Plains reflect the underlying lithology and age of the rocks. The youngest landscapes — the stony rises — have skeletal uniform or gradational soils, whereas the earlier lava flows have deeper soils varying from friable gradational to strongly texture contrast soils. The friable, finely structured brown gradational soils developed on volcanic ash (tuff) around the Red Rock volcano represent some of the most valuable cropping country. The soils developed on the Pliocene sand plains are often sandy, sometimes ferruginised or podsolic (sands with coffee rock or sand over clay) soils. Further south on the marls and limestones, the soils vary from clay-rich (medium or heavy textured) gradational to strongly texture contrast soils and generally heavy (uniform) clays. Much of the area is a natural grasslands plain, bounded by the Western Uplands (WU) to the north, and the coastline and Otway Range - part of the Southern Uplands of Victoria (SU) to the south. |