In geology a bed is the smallest division of 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, usually ranging in thickness from a centimetre to several metres and distinguishable from beds above and below it. Beds can be differentiated in various ways, including rock or mineral type and particle size. The term is generally applied to sedimentary strata, but may also be used for volcanic flows or ash layers.
In a quarry, a bedding is a term used for a structure occurring in granite and similar massive rocks that allows them to split in well-defined planes horizontally or parallel to the land surface.
Three kinds of beds are: parallel beds, cross beds, and graded beds.
In the Image, thin and arranged layers of tuff and shale of Karaj Formation can be seen. The layers are exiting and sloping due to the effect of the Tectonic forces. These layers were formed by the sedimentation of fine-grained sediment and volcanic ash in the Eocene (55 to 38 million years ago) on the seafloor at that time. The thickness of these deposits is now more than 3,300 meters. When the layers are regular and in fairly equal thicknesses, they are called “well-bedded”. This is well seen in the image.
Keywords: bed , bedding , Geology , Geotourism , Iran , Karaj formation , Zamingasht