2. A part of sediment or rock that is different in composition or character, such as being grain sized.
Sediment is a layer of soil, organic material, or rock particles which are no longer in the place where they were formed geologically but which have been redeposited away from their sources.
Characteristics of sediment are closely related to their depositional environment.
The lithofacies are determined by geometry, vertical sequences, and lateral associations.
Lithofacies models or maps, generalized summaries of sediment characteristics of specific depositional environments, serve as guides to interpretation.
Such a map shows variations in the overall lithologic character of a given stratigraphic unit and its changing composition throughout its geographic extent.