Radioactive carbon 14 dating is dependent on

The Problem: Accelerator mass spectrometry (AMS), a sensitive radiometric dating technique, is in some cases finding trace amounts of radioactive carbon-14 in coal deposits, amounts that seem to indicate an age of around 40,000 years. Though this result is still too old to fit into any young-earth creationist chronology, it would also seem to represent a problem for the established geologic timescale, as conventional thought holds that coal deposits were largely if not entirely formed during the Carboniferous period approximately 300 million years ago. I use scintillant every day in my own work to detect H-tagged hormones. But I only use a milliliter at a time - the concept of 800 tons really boggles the mind! So, the physics community has gotten interested in finding out whether and why fossil fuels have native radioactivity. (In comparison, my little hormone vials, here in my above-ground lab, have a background count of about 25 counts per minute for 3.5 milliliters.) So, the physicists want to find fossil fuels that have very little C. Apparently it correlates best with the content of the natural radioactivity of the rocks surrounding the fossil fuels, particularly the neutron- and alpha-particle-emitting isotopes of the uranium-thorium series. Gove and his colleagues told me they think the evidence so far demonstrates that C by local radioactive decay of the uranium-thorium series.

More than 90% of the 16S ribosomal DNA sequences recovered from hydrothermal waters circulating through deeply buried igneous rocks in Idaho are related to hydrogen-using methanogenic microorganisms.

A new species of bacteria found in deep, hot fossil fuels: "Isolation and characterization of Thermococcus sibiricus sp. from a Western Siberia high-temperature oil reservoir." 2001.

These results demonstrate that hydrogen-based methanogenic communities do occur in Earth's subsurface, providing an analogue for possible subsurface microbial ecosystems on other planets.

Gove wrote back the very next day, as did one of his colleagues.

By sheer coincidence, they are currently studying this exact question.