Radiometric dating of rocks absolute age Cam xx
The volcanic effect has a limited distance however. (1980) found that at 200 m away from the source, plants yielded an age in agreement with that expected.
They suggested that the influence of depleted CO2 declined rapidly with increasing distance from the source.
In this page, we consider natural reservoir variations and variations brought about by human interaction].
Radiocarbon samples which obtain their carbon from a different source (or reservoir) than atmospheric carbon may yield what is termed apparent ages.
Thus it was that 1890 wood was used as the modern radiocarbon standard, extrapolated for decay to 1950 AD.
Plants which grow in the vicinity of active volcanic fumeroles will yield a radiocarbon age which is too old. (1980) measured the radioactivity of modern plants growing near hot springs heated by volcanic rocks in western Germany and demonstrated a deficiency in radiocarbon of up to 1500 years through comparison with modern atmospheric radiocarbon levels.
Similarly, this effect has been noted for plants in the bay of Palaea Kameni near the prehistoric site of Akrotiri, which was buried by the eruption of the Thera volcano over 3500 years ago (see Weninger, 1989).
The presence of bomb carbon in the earth's biosphere has enabled it to be used as a tracer to investigate the mechanics of carbon mixing and exchange processes.
Ellen Druffel has called this the silver lining in thermonuclear bomb testing.