Archaeological Dating Methods
Dating methods give archaeology its time depth, allowing sites and finds to be ordered relative to one another and, where possible, placed on an absolute calendar scale.
Definition
The body of relative and chronometric techniques by which archaeologists determine the age of deposits, structures, and artifacts and construct chronological frameworks.
Scope
This area covers the techniques used to establish archaeological chronology, divided into relative methods such as stratigraphy and seriation, and absolute or chronometric methods such as radiocarbon, dendrochronology, and luminescence dating. It addresses the physical principles, sampling requirements, calibration, and uncertainty of each method and how chronologies are built by combining them.
Sub-topics
Core questions
- What is the difference between relative and absolute dating?
- What physical or biological processes allow material to be dated?
- How are radiocarbon dates calibrated to calendar years?
- How are multiple dating methods combined and their uncertainties handled?
Key theories
- Chronometric (absolute) dating
- The use of regular natural processes such as radioactive decay, tree-ring growth, or trapped-charge accumulation to assign ages in years to materials, transforming archaeology after the radiocarbon revolution.
- Relative dating and sequence
- The ordering of deposits and artifacts in relative time through stratigraphy and seriation, providing chronology where absolute dates are unavailable and a framework into which they can be set.
History
Before the mid-20th century, archaeological chronology rested largely on stratigraphy, typology, and cross-dating to historical records. Willard Libby's development of radiocarbon dating in the late 1940s launched a chronometric revolution, soon joined by dendrochronology, potassium-argon, and luminescence methods, and refined through calibration curves that reconcile radiocarbon and calendar time.
Debates
- Radiocarbon calibration and the 'second radiocarbon revolution'
- The recognition that radiocarbon years diverge from calendar years required calibration against dendrochronology, prompting major reinterpretations of prehistoric chronology and ongoing refinement of calibration curves.
Key figures
- Willard Libby
- Martin Aitken
- A. E. Douglass
- R. E. Taylor
Related topics
Seminal works
- aitken1990
- taylorbar2014
- walker2005
Frequently asked questions
- What is the difference between relative and absolute dating?
- Relative dating establishes the order of events, such as which layer is older, while absolute dating assigns an age in calendar or radiocarbon years using measurable physical processes.
- Why must radiocarbon dates be calibrated?
- Atmospheric radiocarbon has varied over time, so raw radiocarbon years do not equal calendar years; calibration curves built from tree rings and other records convert them to calendar ages.