In
geology a
horizon refers to either a bedding surface where there is marked change in the
lithology within a sequence of
sedimentary or
volcanic rocks, or a distinctive layer or thin bed with a characteristic lithology or
fossil content within a sequence. In the interpretation of
seismic reflection data, horizons are the reflectors (or seismic events) picked on individual profiles. These reflectors represent a change in rock properties across a boundary between two layers of rock, particularly seismic velocity and
density.