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This technique is useful to about 9,000 years ago for samples from the western United States using overlapping tree-ring series from living and dead wood.
The Earth's orbital motions (inclination of the earth's axis on its orbit with respect to the sun, gyroscopic precession of the earth's axis every 26,000 years; free precession every 440 days, precession of earth orbit and orbital variations such as perihelion precession every 19,000 and 23,000 years) leave traces visible in the geological record.
An annulus may also be an indication of growth in certain species, similar to dendrochronology.
For example, in fish, it is a series of concentric rings (or annuli) formed in the scales of bony fish.
The result is that along each external "rib" of the cactus is a series of spines arranged in the order they grew in – the oldest spines are at the bottom and the youngest spines are at the top.
These spines can be dated using bomb-spike Carbon-14 and isotopes of carbon (Carbon-13) and oxygen (Oxygen-18) may be used to infer past climate (e.g.
In conjunction with techniques such as radiometric dating, the technique can be used to construct and calibrate the geomagnetic polarity time scale.
This is one of the dating methodologies used for sites within the last 10,000 years. Thellier in the 1930s and the increased sensitivity of SQUID magnetometers has greatly promoted its use.
Archaeologists use tree-ring dating (dendrochronology) to determine the age of old pieces of wood.It also draws heavily from the field of ecophysiology, a branch of Biology, to ascribe spine or thorn characteristics to particular environmental or physiological variables.