Volcano photo

Can the age of rocks be measured accurately?


Q1: Why do rock dating techniques give widely different answers?


  • They analyse a rock sample, and if it gives the 'wrong' age, they just discard that result.
  • They repeat the analysis with another sample from the same rock.
  • They keep doing this, until they get an answer they're happy with!
  • Rocks from volcanic events within the last 200 years, can return "dates" anywhere from 1 million to 100 million years or more!
  • A standard question they generally ask, when you take a rock to be measured is: "What age are you expecting?"
  • I.e. They'll test the rock until they obtain an answer that fits your "assumption," because they are just guessing.
  • They use rocks to date fossils, and fossils to date rocks - circular logic.

Solution: Nobody knows how old rocks are.


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