7 - Vertic Features

Abstract

Vertic features result from shrink-swell processes, pedoturbation (or churning), and ateral shearing due to the alternating water regime in clayey materials. Research on the micromorphology of vertic features has been carried out since the 1960s. Vertic features, resulting from shrink-swell processes, vertical mixing and lateral shearing, due to alternating wetting and drying of clayey materials, are very prominent and rather easy to identify in thin sections. Vertic materials show a characteristic combination of micromorphological features. The most relevant are striated b-fabrics, an open porphyric c/f-related distribution, a blocky microstructure, a heterogeneous groundmass with incorporated dark aggregates, Fe/Mn oxide pedo features and, in more arid regions, carbonate and gypsum pedofeatures. The micromorphological study of vertic features in modern soils and palaeosoils can provide reliable information on the genesis and evolution of the soil and on long-term and short-term environmental changes and trends.