A paleosol is an ancient inactive soil preserved by burial in a stratigraphic succession or prolonged exposure at the surface. Its study is the object of Paleopedology. Due to the episodic nature of sediment accumulation, it is common for a continental sedimentary sequence to contain isolated, overlapping or multiple paleosols.[1]​[2]​.

They are mainly recognized by the presence of: a) traces of roots of variable morphology and concentration, such as rhizoliths"), rhizoconcretions"), rhizohalos"), paleorizospheres"), etc.; b) main and subordinate horizons, defined by compositional, structural or color changes, and c) edaphic macro- and microstructures such as aggregates (peds), glébulas" (nodules, concretions or specks), cutanes"), pedotubules"), and plasmic microfactory").[1]

Paleosols, lithified or not, can be found in deposits from the Precambrian to the Quaternary, in siliclastic, volcanic-pyroclastic or carbonatic sequences, mostly continental (fluvial, eolian, deltaic, marginal lacustrine, glacial, etc.), although they are also possible in marine successions due to rapid decreases in sea level. They originate in periods of landscape stability (no erosion, minimal or no sedimentation), when the rate of pedogenesis exceeds that of sedimentation. Therefore, they reflect a complex balance between accumulation, weathering, erosion, and denote a depositional hiatus of variable temporal extent (i.e. diastema, unconformity "Unconformity (geology)")).

Paleosols are useful in different types of geological analysis. In the stratigraphic aspect and through knowledge of their degree of development and frequency, they allow the evaluation of the integrity or continuity of a succession, the presence of diastemas or non-depositional discordances, allocyclic controls on sedimentation and the accumulation rate at different scales. Likewise, they serve to subdivide sections or sections within depositional sequences and have significant value as guide levels for surface and subsoil correlation. At the basin scale and from a tectonic perspective, paleosols facilitate the evaluation of subsidence rates.

Given that a paleosol can be considered the trace of a past ecosystem and also a preservation environment for many types of corporeal fossils,[1]​ its application in paleoenvironmental studies (paleoclimatic, paleoecological and paleogeographic) is relevant. Paleosols allow us to recognize different characteristics of the ancient climate and environment in which the soil originated, for example climatic seasonality, precipitation and average annual temperature, depth of the water table, certain features of the paleorelief, type of vegetation (jungle, wooded, herbaceous, swampy, etc.), root systems and soil fauna, whether invertebrates (ants, beetles, bees, worms, crustaceans) or vertebrates. (rodents, reptiles). By adding geochemical (organic and inorganic) and mineralogical studies, it is possible to analyze the chemical and biological weathering suffered by the original paleosol materials and thus recognize changes in the fossils.