To: HPilot who wrote (31557 ) 1/5/2011 1:48:34 PM From: Jacques Chitte 1 Recommendation Respond to The nice thing about isotope ratios is that they tell you the age of the carbon source. Fossil sources (coal, oil and volcanic vent gas) have a C14 content of zero, since C14 has a half-life of 5730 years. Biospheric carbon has a "normal" c14 content, because it was made entirely from atmospheric carbon dioxide during the plant's lifetime, and animals eat fresh plant matter (carnivores do so indirectly). The mechanism for making carbon radioactive (cosmic rays hitting nitrogen) occurs at a fixed rate. C14 ratios can be measured precisely, and the drop gives a proportion of "extra" fossil carbon. So, how much of this is volcanic, and how much of it has been burned in the quest for modern living?
