What is involved in the process of radiocarbon dating

When archaeologists have access to the historical records of civilizations that had calendars and counted and recorded the passage of years, the actual age of the archaeological material may be ascertained—provided there is some basis for correlating our modern calendar with the ancient calendar.With the decipherment of the Egyptian hieroglyphics, Egyptologists had access to such an absolute timescale, and the age, in calender years, of the Egyptian dynasties could be established.Furthermore, Egyptian trade wares were used as a basis for establishing the age of the relative chronologies developed for adjoining regions, such as Palestine and Greece.

what is involved in the process of radiocarbon dating-36what is involved in the process of radiocarbon dating-35

Absolute dating can be achieved through the use of historical records and through the analysis of biological and geological patterns resulting from annual climatic variations, such as tree rings (dendrochronology) and varve analysis.

After 1950, the physical sciences contributed a number of absolute dating techniques that had a revolutionary effect on archaeology and geology.

These techniques are based upon the measurement of radioactive processes (radiocarbon; potassium-argon, uranium-lead, thorium-lead, etc.; fission track; thermoluminescence; optically stimulated luminescence; and electron-spin resonance), chemical processes (amino-acid racemization and obsidian hydration), and the magnetic properties of igneous material, baked clay, and sedimentary deposits (paleomagnetism).

Other techniques are occasionally useful, for example, historical or iconographic references to datable astronomical events such as solar eclipses (archaeoastronomy).

In dendrochronology, the age of wood can be determined through the counting of the number of annual rings in its cross section.

Tree ring growth reflects the rainfall conditions that prevailed during the years of the tree's life.

Because rainfall patterns vary annually, any given set of tree ring patterns in a region will form a relatively distinct pattern, identifiable with a particular set of years.

By comparing the pattern of tree rings in trees whose lifespans partially overlap, these patterns can be extended back in time.

By matching the tree rings on an archaeological sample to the master sequence of tree ring patterns, the absolute age of a sample is established.

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