Stratigraphy: Meaning (information, definition, explanation, facts)

Stratigraphy is that branch of geology concerned with understanding the geometrical relationships between sedimentary rocks and soils. Key elements of stratigraphy are understanding how certain geometries arise and what these geometries mean in terms of depositional environment. One of stratigraphy's basic concepts is codified in the Law of Superposition, which simply states that, in an undeformed stratigraphic sequence, the oldest strata occur at the base of the sequence.

The study of stratigraphic sequences has led to some important results and given rise to the discipline of sequence stratigraphy, such as the Vail curve, which attempts to define a global historical sea-level curve according to inferences from world-wide stratigraphic patterns. Stratigraphy is also commonly used to delineate the nature and extent of hydrocarbon-bearing reservoir rocks, seals and traps (see petroleum geology).

Archaeological stratigraphy

In the field of archaeology, soil stratigraphy is used to better understand the processes that form and protect archaeological sites. The law of superposition holds true and this can help date finds or features from each context as they can be placed in sequence and dates interpolated. Phases of activity can also often be seen through stratigraphy especially when a trench or feature is viewed in section (profile), As pits and other features can be dug down into earlier levels, not all material at the some absolute depth is necessarily of the same age, but close attention has to be payed to the archeological layers. The Harris-matrix is a tool to depict complex stratigraphic relations, as they are found, for example, in the contexts of urban archaeology.