Usporedite metode

	Frequency Seriation	Radiocarbon Calibration
Područje	Arheologija	Arheologija
Obitelj	Process / pipeline	Process / pipeline
Godina nastanka	1962	2020
Tvorac	Leslie Spier; James A. Ford (developed from W. M. F. Petrie's sequence dating)	Hans Suess (first curves); IntCal Working Group (P. J. Reimer et al.)
Vrsta	Relative-chronology ordering of assemblages by type proportions	Probabilistic conversion of radiocarbon ages to calendar ages
Temeljni izvor	Lyman, R. L., & O'Brien, M. J. (2006). Measuring Time with Artifacts: A History of Methods in American Archaeology. University of Nebraska Press. ISBN: 9780803280526	Reimer, P. J., et al. (2020). The IntCal20 Northern Hemisphere Radiocarbon Age Calibration Curve (0-55 cal kBP). Radiocarbon, 62(4), 725-757.
Drugi nazivi	Frequency Seriation Dating, Battleship-Curve Seriation, Proportional Seriation	14C Calibration, IntCal Calibration, Calendar Calibration of Radiocarbon Dates
Srodne	3	3
Sažetak	Frequency seriation is a relative-dating technique that orders archaeological assemblages in time by the changing proportions of the artifact types they contain. Its premise is that any cultural type is introduced, gradually becomes popular, peaks, and then declines, so that the relative frequency of a type traces a single rise-and-fall curve through time. By rearranging the rows of a type-by-assemblage abundance table until every type's frequency forms one continuous unimodal sequence, the analyst recovers an ordering interpreted as chronological. Drawn as horizontal bars, these curves take the lens or 'battleship' shape that gives the method its popular name. Frequency seriation grew out of W. M. F. Petrie's sequence dating and was formalized for proportional data by mid-twentieth-century Americanists such as James A. Ford, becoming a backbone of culture-historical chronology before absolute dating was widely available.	Radiocarbon calibration converts a laboratory radiocarbon measurement into a probability distribution over actual calendar years. It is necessary because the assumptions behind a raw radiocarbon age are not exactly true: the concentration of carbon-14 in the atmosphere has varied over time, so a measured radiocarbon age does not equal a calendar age. Calibration corrects for this by comparing the measurement against an internationally agreed curve — currently IntCal20 — that records the relationship between radiocarbon age and calendar age, reconstructed from precisely dated tree rings, corals, speleothems, and other archives. Because the curve wiggles, calibration typically yields an irregular, sometimes multi-peaked range of calendar years rather than a single date, and that range is the proper expression of a radiocarbon result.