How has radiocarbon in fossil fuels survived for millions of years?

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Discussion Overview

The discussion centers around the presence of radiocarbon (C-14) in fossil fuels and the implications of its half-life on dating methods. Participants explore the longevity of C-14 in fossil fuels, the decay process, and alternative dating methods suitable for ancient organic materials.

Discussion Character

  • Exploratory
  • Debate/contested
  • Technical explanation

Main Points Raised

  • One participant questions how C-14 can survive in fossil fuels for millions of years given its half-life of approximately 5,750 years, noting that most C-14 would decay within 50,000 years.
  • Another participant challenges the existence of C-14 in fossil fuels, referencing a NOAA source that states all radiocarbon initially present has decayed away in ancient organic matter.
  • A different participant suggests using alternative dating methods, such as Potassium-Argon dating, which relies on elements with longer half-lives, to date fossils instead of relying on C-14.
  • One participant mentions the low natural occurrence of C-14 in the environment and its measurement despite its rarity, emphasizing that fossil fuels primarily consist of C-12 and C-13.
  • Another participant discusses the C-12/C-13 ratio in the atmosphere, arguing that the burning of fossil fuels alters this ratio and provides evidence of their carbon source.

Areas of Agreement / Disagreement

Participants do not appear to reach a consensus on the presence of C-14 in fossil fuels, with some asserting its absence due to decay while others question this assertion. Multiple competing views regarding dating methods and the implications of carbon ratios are present.

Contextual Notes

There are unresolved assumptions regarding the measurement of C-14 in fossil fuels and the implications of carbon isotopes in atmospheric studies. The discussion reflects varying interpretations of sources and the complexities of dating ancient organic materials.

JPKerz
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I have a fair understanding of radioactivity and a general grasp of molecular dating, but I was curious as to how radiocarbon in fossil fuels has survived millions of years despite its half life being only 5,750ish years. From what I've seen through minimal research is that most of the C14 in a sample is decayed by 50,000 years. Any information on the topic would be appreciated.
 
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Why do you think there is C14 in fossil fuels.? Do you have a source or a measurement? This NOAA web site says the following, "Fossil fuels are, well, fossils, and are millions of years old. Because of this, all of the radiocarbon initially present has decayed away, leaving no 14C in this ancient organic matter."

This Wikipedia site also has some relevant info.
 
Because all C14 has decayed after 50,000 years, you need to use another element with a longer half-life, like the Potassium->Argon decay:

https://en.wikipedia.org/wiki/K–Ar_dating

Unlike carbon dating, the sample can be taken from the rock surrounding the fossil, which is good because you need a big bag of rocks to have sufficient Potassium for an accurate dating. For a C14 dating, you need to destroy part of the object itself
 
The natural occurrence of C-14 in the environment is only about 1 part per trillion. Even at this rarified level of concentration, it is nevertheless possible to measure the radioactivity coming from the decay of this isotope.

https://en.wikipedia.org/wiki/Carbon-14

Fossil fuels are for the most part made up of plain old C-12 and C-13.
 
Perhaps you have misread something? Ratio of C13/C12 in atmosphere is used to show that most of the atmospheric carbon dioxide comes from the burning of the fossil fuels. The rationale behind is that plants prefer C12 during photosynthesis, so the C12/C13 ratio in fossil fuels is much higher than in abiogenic deposits containing carbon. Now that we burn fossil fuels at a high rate most of the carbon dioxide produced is C12 rich so the C13 gets diluted.
 

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