Bed (geology)
In geology a bed is the smallest division of rock or deposit. It is a geologic formation or stratigraphic rock series marked by well-defined divisional planes (bedding planes) separating it from layers above and below.
A bed is the smallest lithostratigraphic unit. It ranges in thickness from a centimetre to several metres. It can be distinguished from beds above and below it by rock or mineral type and particle size. The term is usually applied to sedimentary strata, but may also be used for volcanic flows or ash layers.
In a quarry, bedding is a term used for a structure occurring in granite and similar rocks which allows them to split in well-defined planes horizontally or parallel to the land surface.
Engineering
In geotechnical engineering a bedding plane often forms a discontinuity that may have a large influence on the mechanical behaviour (strength, deformation) of soil and rock masses. This is important in, for example, tunnel, foundation, or slope construction.
Bed (geology) Media
Beds of sedimentary rock at Parque Geológico do Varvito, Itu, São Paulo, Brazil
Originally horizontal beds of sedimentary rock were tilted by the Alpine orogeny, at Angles, Alpes-de-Haute-Provence, France
Beds of lava flows exposed in Chasm Provincial Park, British Columbia, Canada
Vertical cross-sections of bed sequences to illustrate (from top to bottom) the Law of Superposition, the Law of Original Horizontality, the Law of Lateral Continuity, and Cross-Cutting Relationship
