Tuesday, July 21, 2015

What Time Does This Date Stop At The Industrial Revolution?

As an archaeological beneficiary ( Olmec & Tibetan divisions ) of accelerator mass spectrographic radiocarbon dating, I cannot view with disinterest what fossil fuel burning does to that subtle art.

The trouble is that while an accelerator mass spec can literally count the carbon 14 atoms in a fleck of lint, extracting a date from the data also entails comparing that number to the number of stable carbon  12 & 13 atoms in the beam. 

Anything that changes the ratio renders the dates dodgy.

Archaeology reports that  
according to Heather Graven of Imperial College London.
 Fossil fuels are so old that they contain no radioactive carbon-14...so fossil fuel emissions in the atmosphere that are taken up by plants make an object seem to be older than it really is. For example, at the rate that fossil fuel emissions are increasing, by 2050, a new t-shirt would have the same radiocarbon date as a 1,000-year-old robe.