Carbon-14 and Radiocarbon Dating

Category: Science & Technology | GS Paper III

SEO Title: Carbon-14 Dating: Half-Life, Principle, Applications and Limitations in Archaeology

UPSC Notes

Carbon-14 is a radioactive isotope of carbon used to estimate the age of organic materials.

  • Half-life: Approximately 5,730 years.

  • Formation: Cosmic-ray neutrons interact with nitrogen-14 in the upper atmosphere, producing carbon-14.

  • Entry into living organisms: Carbon-14 enters the food chain through atmospheric carbon dioxide and biological processes.

  • Radioactive decay: Carbon-14 decays by beta emission into nitrogen-14.

  • Radiocarbon dating: Developed by Willard Libby, who received the Nobel Prize in Chemistry in 1960.

  • Age range: Commonly useful for organic samples up to around 50,000 years old.

  • Modern technique: Accelerator Mass Spectrometry (AMS) can measure very small quantities of carbon-14.

  • Calibration: Tree rings and other chronological records improve dating accuracy.

  • Applications: Archaeology, biological research and tracing carbon movement.

  • Limitation: It is not the standard method for dating ancient rocks; uranium–lead and potassium–argon methods are used for suitable geological materials.

Key Pointers for Prelims

  • Carbon-14 half-life: 5,730 years.

  • Scientist: Willard Libby.

  • Best suited to organic remains.

  • Radiocarbon dates require calibration.

  • The source mentions archaeological samples from Keeladi, Tamil Nadu.