Subplasticity in Australian soils. I. Description, occurrence, and some properties

Abstract

The origin of the term 'subplasticity', its connotation in the description and properties of some Australian soils, and the occurrence and distribution of subplastic soils are discussed. Although the term was originally descriptive, the degree of subplasticity being determined by field texturing of soils, it has come to mean also that the soil very strongly resists dispersion into primary particles by both mechanical and chemical means. The results of some early attempts at dispersion are presented (a series of following papers describes properties in more detail), and comparison is made with various other soils, which show subplasticity and resistance to dispersion to a lesser degree, or normal dispersion properties. A high degree of subplasticity and high resistance to dispersion are associated, in the majority of cases, with soils formed in parna, an aeolian clay, as parent material.