The 6 proton 6 neutron atoms are said to have a mass of 12 and are referred to as "carbon-12." The nuclei of the remaining one percent of carbon atoms contain not six but either seven or eight neutrons in addition to the standard six protons.
They have masses of 13 and 14 respectively and are referred to as "carbon-13" and "carbon-14." If two atoms have equal numbers of protons but differing numbers of neutrons, one is said to be an "isotope" of the other.
Our staff cooperates with interpretation of results.
Samples can be send to us as specified at the customer page . This isotope is produced in the upper atmosphere by collisions of cosmic ray produced neutrons with nitrogen.
Levels of C can represent either mixtures of modern and dead carbon or carbon that was fixed from the atmosphere less than 50,000 years ago.
Shell may succumb to isotopic exchange if it interacts with carbon from percolating ground acids or recrystallization when shell aragonite transforms to calcite and involves the exchange of modern calcite.
However, as with any dating technique there are limits to the kinds of things that can be satisfactorily dated, levels of precision and accuracy, age range constraints, and different levels of susceptibility to contamination.
Radiocarbon dating is especially good for determining the age of sites occupied within the last 26,000 years or so (but has the potential for sites over 50,000), can be used on carbon-based materials (organic or inorganic), and can be accurate to within ±30-50 years.
A hydrocarbon found in beach sediments, for example, might derive from an oil spill or from waxes produced by plants.
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