Introduction - Geotechnics of Organic Soils and Peat - page 2

Figure 1.1 Soil profile of a weathering in a metamorphic rock (amphibole schist) ( modified after Raj,
1993).
Figure 1.2 Distribution of tropical residual soils ( after F.A.O.World Soil Map).
soil. This soil typically retains many of the characteristics of the parent rock. For
example, decomposed granite will result in sandy residual soil.
In a tropical region, residual soil layers can be very thick, sometimes extending for
hundreds of metres before reaching unweathered rock (Figure 1.1). Cooler and more
arid regions normally have much thinner layers, and often no residual soil at all. The
worldwide distribution of residual soil is shown in Figure 1.2.