This document provides an overview of archaeological dating techniques, dividing them into relative dating methods and absolute dating methods. Relative dating techniques like stratigraphy, seriation, and fluorine dating allow archaeologists to determine the order of artifacts from oldest to youngest without providing specific calendar dates. Absolute dating techniques like dendrochronology and radiocarbon dating provide calendar year dates by relying on principles of radioactive decay, with radiocarbon dating being the most common method for dating organic materials from 500-50,000 years ago. The document discusses issues with various dating techniques and their appropriate applications.

1. Introduction to Archaeological
Dating Techniques

2. Dating Techniques
Two major categories:
Relative Dating
Orders items from oldest to youngest
Does not give a specific date
Absolute Dating
Also called chronometric dating
Gives a date in terms of calendar year

3. Relative Dating
Analysis during Excavation:
Stratigraphy (layers of deposits, natural
and human made)
Law of Superposition
•Older materials are typically on the bottom,
younger materials on the top
•Except when they are not!—sometimes old
material is dug up and reused, natural
formation processes redeposit materials, etc.
•Why context is so important

4. Relative Dating
Seriation: Linking
Artifact Typologies with
Temporal Associations
•Qualitative (changes in
types of artifacts through
time) or Quantitative
(changes in the amount of
different artifacts through
time)

5. Relative Dating
Seriation
•Very important to maintain
context, understand relative
frequency of artifacts
•Charting time-sensitive
artifacts forms “Battleship
Curves”
•Shows change in relative
frequency of styles of artifact
through time

6. Relative Dating
One more Relative dating technique:
FUN Dating (Fluorine, Uranium and
Nitrogen)
•Buried bones slowly lose nitrogen and absorb
fluorine and uranium through time
•Amount of these elements in bones can be
compared to see which were buried longer
•Rates of absorption are locally specific, cannot
compare bones from different regions

7. Absolute Dating
Many different types:
•Dendrochronology—tree ring dating
•Radiometric techniques—based on
principles of radioactive decay
•And more!

8. Dendrochronology
•Earliest form of absolute dating
•First used in the American Southwest

9. Dendrochronology
• Based on the annual growth of trees, each
ring representing a new year of growth
• Rings vary in thickness according to the
year, over time will have a distinct pattern
of rings
• Patterns of rings are matched from newer
to older trees
• Limited to areas where trees preserve,
only goes back a limited time, less than
10,000 years

10. Absolute Dating
Radiometric Dating Techniques
•Based on principles of atomic decay, where
radioactive parent isotopes decay into
daughter elements
•Rate of decay is known and is measurable
•When decay began is known

11. Radiometric Dating
Radiocarbon Dating: most common
•Must use organic materials, such as charcoal, bone,
or plant matter
•All organic life takes in carbon from their
surroundings
•14
C is an unstable carbon isotope; 12
C is a stable
carbon isotope
•When organism dies, only the 14
C begins to decay
•Half-life of 14
C (after death of organism) is
approximately 5,730 years—meaning after 5,730
years, half of the 14
C in the living organism is gone

12. Radiometric Dating
Radiocarbon Dating: Issues
•Amount of 14
C in the atmosphere has changed in
the past!
•Dates must be calibrated to reflect true date
•Must have adequate amount of sample material,
avoid contamination
•Older techniques needed 10-20 grams, newer AMS
technique need very small sample
•Technique limited to dates from 500 to 50,000
years—after 50,000 years, there’s not enough 14
C left
to measure

13. Radiometric Dating
Other Radiometric Dating Techniques
(see your textbook)
•Potassium-Argon: good for much older
samples, dates into the billions of years, uses
volcanic material
•Uranium: dates limestone cave deposits, useful
for “in-between” dates
•Fission-track: uses volcanic rocks or glass,
typically older dates
•Thermoluminescence: pottery and burned clay