With this system, an event that occurred in 1000 B. Relative dating methods allow one to determine if an object is earlier than, later than, or contemporary with some other object.If archaeologists know how pottery styles, glazes, and techniques have changed over time they can date sites based on the ratio of different kinds of pottery.
Other methods include fluorine dating, nitrogen dating, association with bones of extinct fauna, association with certain pollen profiles, association with geological features such as beaches, terraces and river meanders, and the establishment of cultural seriations.
Cultural seriations are based on typologies, in which artifacts that are numerous across a wide variety of sites and over time, like pottery or stone tools.
They do not tell us when an event happened in years before the present. This usually means that there is a 2/3 probability that the actual date of the event was within the range of 300-380 B. The 2/3 probability is what statisticians refer to as one standard deviation.
For example, in comparing the cross-section of the series of geological strata illustrated below, level 4 is older than 5 because it is below it. At a higher probability, the plus or minus factor will be larger.
Stratigraphic dating is based on the principle of depositional superposition of layers of sediments called strata.