Following these unreliable results, a few bulk peat samples were dated to help assess if any of the plant macrofossil-derived dates were reliable. This study evaluates the possible sources of error but is unable to single out one clear cause.
The fulvic acid fraction, although normally younger than the corresponding humic acid and humin fractions, has very little effect on a combined date in these samples.
However, it is removed from all samples prior to dating in order to remove any carbonates which could contaminate samples.
Four fen peat sequences in northern Finland were dated by the accelerator mass spectrometry (AMS) radiocarbon method in order to study past peatland dynamics and carbon accumulation patterns.
Initially, plant macrofossils were used for dating.
In The Cosmic Story of Carbon-14 Ethan Siegel writes: The only major fluctuation [in carbon-14] we know of occurred when we began detonating nuclear weapons in the open air, back in the mid-20th century.
If you ever wondered why nuclear tests are now performed underground, this is why.
For each slice the remaining peat was then split into humic acid, humin and fulvic acid fractions and radiocarbon dated.
This research demonstrates that significant variations can occur in the radiocarbon content of discrete chemically defined fractions of peat. The results from the four columns of peat are highly variable and mutually inconsistent.
At an archaeological dig, a piece of wooden tool is unearthed and the archaeologist finds it to be 5,000 years old.