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Archeology for Interpreters > 5. How Do Archeologists Figure Out How Old Things Are?

Relative dating


(image) Cross dating chart

Cross dating chart. (Heather Hembrey, University of Maryland)

Cross-dating is a technique used to relatively date objects based on consistencies in stratigraphy between parts of a site or different sites, and objects or strata with a known relative chronology. A stratum containing artifacts that were originally deposited across the area at the same level may, over time, end up at different levels below the ground surface due to disturbances. Cross-dating allows archeologists to compare soil characteristics and artifacts within each stratum to determine their relationship relative to each other.