A soil catena on denuded laterite profiles in Queensland

Abstract

A catena comprising 10 distinct zones on variously denuded laterite profiles in central Queensland is described. Red and yellow earths occur on intact or slightly stripped uplands. On denuded weathered zones, solodized solonetz, solodic, and related soils with abrupt textural differentiation have formed on intermediate slopes and saline-alkali clay soils occur on lower slopes. Soil differences are related partly to differences in parent materials and partly to the spread of weathering and erosion products across the topographic sequence. The catena either in whole or in part is repeated over wide areas. The weathering of primary minerals in parent rocks appears to be the most likely source of salts that led to the formation of halomorphic soils. The soluble materials have been leached and redistributed by surface and subsurface seepage from denuded mottled and pallid zones upslope. The clay soils appear to have formed mainly on materials derived from shales that were originally overlain by arenaceous upper Tertiary sediments, but some reworking of these materials may have occurred. Montmorillonoid clays have been preserved from deep weathering by their impermeable nature.