The zinc isotope signatures in ancient human teeth from Laos have remained unchanged since burial, because their chemical patterns match those of modern teeth and show no link to elements that...
Mechanism
Synthesis from 1 study
When animals eat, their teeth lock in a zinc fingerprint that matches their diet. Once the tooth is done growing, that fingerprint stays frozen in a super-stable mineral that doesn’t react with dirt or water, even after tens of thousands of years. That’s why scientists can still read what ancient...
Most probable mechanism
When animals eat, zinc from their food gets absorbed and locked into their developing teeth in a pattern that reflects what they ate. Once the tooth is fully formed, the zinc becomes part of a very stable mineral structure that doesn’t change even after thousands of years buried in the ground, so the original chemical signal stays intact.
Zinc from dietary sources is absorbed through the digestive tract and distributed in the body, with heavier isotopes preferentially retained in tissues of herbivores due to plant-based diets containing higher concentrations of heavy zinc isotopes.
During tooth formation, zinc is incorporated into the enamel bioapatite crystal lattice in proportions that mirror the isotopic composition of circulating zinc in the bloodstream at the time of mineralization.
The enamel bioapatite structure is highly resistant to chemical exchange after burial, preventing the uptake of foreign zinc or isotopic alteration from surrounding soil minerals, even when other organic components like collagen degrade.
The spatial distribution of zinc concentration within enamel, decreasing from outer to inner layers, matches the pattern seen in living animals and confirms that the zinc signal was deposited during life and not introduced postmortem.
Evidence from Studies
Supporting (1)
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Zinc isotopes in Late Pleistocene fossil teeth from a Southeast Asian cave setting preserve paleodietary information
Contradicting (0)
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Gold Standard Evidence Needed
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