3 ms·

How do they know it is 130 million years old?

• thecopy 10y ago
  Carbon dating, presumably.
  • muricula 10y ago
    Carbon dating is not a magic bullet and would not work here. C14 dating can't be used to date samples more than 50,000 years ago because C14 has a relatively short half life and most of it would have decayed by then(0). Additionally, C14 dating doesn't work on fossils because much of the carbon has been replaced by different minerals. Uranium lead dating is typically held as accurate for rocks between 1 million and 4.5 billion years ago, so they probably used this. However, there may not be any uranium in the fossil itself so they may have looked at stratigraphic layers of volcanic ash, which would have sufficient amounts of uranium, above or below the fossil to arrive at this date(1). This is really speculation without looking at the study where I'm sure they discuss it in detail. (0) https://en.m.wikipedia.org/wiki/Radiocarbon_dating https://en.m.wikipedia.org/wiki/Radiocarbon_dating (1) https://en.m.wikipedia.org/wiki/Uranium%E2%80%93lead_dating https://en.m.wikipedia.org/wiki/Uranium%E2%80%93lead_dating