ARCHAEOLOGICAL DATING TECHNIQUES

SIR MORTIMER WHEELER “new archaeology” excavated urban centres layer by layer  “The important thing is that the archaeologist must know his dates and how to use them.”

RELATIVE /ABSOLUTE  RELATIVE TECHNIQUES  Stratigraphy and Seriation  Typology and Cross Dating  Fluorine  Obsidian Hydration  Pollen Analyses  ABSOLUTE TECHNIQUES  Radio Carbon Dating  Potassium Argon Dating  Thermoluminescence  Electron Spin Resonance  Dendrochronology

RELATIVE DATING  Relative dating is an invaluable tool, but does not tell us WHEN an event occurred, just the ORDER in which events occurred. The oldest technique for establishing the actual ages of deposits is to use artifacts of a known age.  These can be coins with minting dates stamped on them, writings with dates included, or objects that we know were only manufactured during a certain time.

STRATIGRAPHY  Stratigraphy is the study of strata, or layers.

THE LAYERS OF TROY

FLUORINE DATING  Fluorine is an element that is found in most ground water around the world. It can be used as a relative dating technique.  Skeletal remains buried in the earth are subject to a wide range of chemical changes. One of these changes can occur when ground water comes into contact with the remains. The ground water inundates the bone remains with a solution of minerals drawn from local soils.  Fluorine dating is chiefly of value in determining whether bone implements or human skeletal remains found in association with other bones were buried at the same time. It was fluorine dating that was instrumental in the debunking of Piltdown Man.

Weakness of Relative Dating  The potential flaws in relative dating are obvious. Simply assuming that an object is older because it was found at a lower depth in the record is only subjective science.  There are many instances of deep holes being dug for rubbish pits or to locate well water that protrude into the record of older strata injecting more modern material as they are filled in over time.  Landslides and slips can completely change the topography of an entire site burying what was once on top by that which is much older, hence reversing the strata layers

ABSOLUTE DATING  A more precise and accurate system is known as absolute dating and can in most circumstances provide a calendar year to the object. Since 1950 there has been a transformation in the dating techniques of archaeologists.  Absolute dating is highly dependant on laboratory analysis. There are a number of techniques that have come to archaeology through the nuclear research efforts during WW2.

RADIO CARBON DATING  Radiocarbon dating uses the biological assumption that all living things absorb carbon, both ordinary carbon, C12, and radioactive carbon, C14, into their living tissue.  C14 dating can only be used on organic matter.

DENDROCHRONOLOGY  Dendrochronology is another traditional technique for establishing the absolute date of events.

Weaknesses in Dendrochronolgy  In some areas of the world, particularly in the tropics, the species available do not have sufficiently distinct seasonal patterns that they can be used.  Where the right species are available, the wood must be well enough preserved that the rings are readable. In addition, there must be at least 30 intact rings on any one sample.

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