Marker Bed

marker bed

[′märk·ər ‚bed] (geology) A stratified unit with distinctive characteristics making it an easily recognized geologic horizon. A rock layer which accounts for a characteristic portion of a seismic refraction time-distance curve. key bed

Marker Bed

 

a bed in rock strata that is distinctive owing to structure, color, great density, the presence of concretions and fossils, or any other features that make it possible to trace it when correlating sections and preparing geological maps. It differs in principle from the stratigraphic horizon, which is based on a set of organic remains and includes beds of different facies types.