What is a soil in geology ?

Soil : definition

A soil is a superficial formation resulting from the alteration of the underlying rocks. A soil is usually made up of different levels or horizons, together forming the soil profile.

Depending on the climate, different soil families have been described. In temperate climates, soils are mainly made up of clay minerals and organic matter. In a humid tropical climate, laterite, a ferruginous soil, will dominate.