History of radiometric dating
Actually, that ratio may have been quite different.For example, a worldwide flood would uproot and bury preflood forests.Half of it will decay in about 5,730 years to form nitrogen.
The helium still locked in the samples was studied as well as the rate at which the helium diffused from the rock.
Cosmic radiation striking the upper atmosphere converts about 21 pounds of nitrogen each year into radiocarbon (carbon-14).
Most carbon-14 quickly combines with oxygen to form radioactive carbon dioxide, which then spreads throughout the atmosphere.
Radiocarbon ages do not increase steadily with depth, as one might expect. In other words, the concentration of carbon-14 is unexpectedly low in the lower organic layers.
As one moves to higher and higher layers, this concentration increases, but at a decreasing rate.