3 ms·

The age of the rocks it was found in.

• smhenderson 5y ago
  OK, sure, makes sense. But how do they know how old the rocks are? If not by carbon dating that is...
  • dharmab 5y ago
    https://www.nature.com/scitable/knowledge/library/dating-rocks-and-fossils-using-geologic-methods-107924044/ https://www.nature.com/scitable/knowledge/library/dating-roc... This page has a table of different dating methods that work on minerals and the time ranges to which they are accurate.
  • AlotOfReading 5y ago
    The "Re-Os" bit indicates that it was Rhenium-Osmium dating of black shale (a sedimentary rock commonly found on paleo-coastlines) in the formation. One of the major differences between the paleontologists and archaeologists is their opinion of shale and other mudstones. Paleontologists love the stuff, archaeologists hate it.
  • Tagbert 5y ago
    Geologists and paleontologist usually use multiple methods to estimate age. Carbon works well for young deposits. Uranium dating can be used for much older materials. As AlotOfReading mentioned Rhenium-Osmium. Sometimes they can use Oxygen ratios in inclusions in Zircon crystals. There are other more specialized measures. Using multiple methods can help calibrate each other.
  • smhenderson 5y ago
    Thanks everyone, very interesting and probably worth further reading!