All of the artifacts in a given stratum will be of approximately the same age, while those in strata above or below will be younger or older respectively.Cross-dating can indirectly establish a date for artifacts and sites.Artifacts such as stone points and pottery were made in distinctive styles through time.
If an arrow point was found in association with a hearth that was radiocarbon dated to be 500 years old, it is assumed that the arrow point is the same age.
When that style of arrow point is found at another site, the archaeologist would assign the site and the arrow point an age of approximately 500 years.
Often cross-dating is the only method archaeologists have to determine the age of sites.
Natural materials such as rocks, soil, and traces of plants and animals settle on the earth’s surface and over time can accumulate in layers.
Each layer, or stratum, may be distinguished by its physical characteristics: color, texture, and structure.
Similarly, materials of human origin are also deposited onto the earth’s surface.In archaeological sites, natural and human-generated materials occur together in layers.These layers, called strata, form a record of past events that archaeologists analyze and interpret.The materials deposited first are the oldest and are always found at the bottom of a given stratigraphic section.The most recently deposited materials are the youngest and are always at the top. It always applies except when some type of disturbance has occurred.Strata in archaeological sites provide archaeologists with temporal and spatial information.