in archaeology, the general meaning of horizon is a distinctive type of sediment, artifact, style or other cultural trait that is found across a large geographical area, from a limited time period. the term derives from similar ones in geology, horizon or marker horizon, but where these have natural causes, archaeological horizons are caused by man. most typically there is a change in the type of pottery found, and in the style of less frequent major artefacts. across a horizon the same type of artefact or style is found very widely over a large area, and it can be assumed that these traces are approximately contemporary.