it’s usually taken to be the fact that as carbon dioxide concentrations in the atmosphere increase, the 1 per cent of co2 that’s the heavier carbon isotope ratio c13 declines in proportion.
it’s usually taken to be the fact that as carbon dioxide concentrations in the atmosphere increase, the 1 per cent of co2 that’s the heavier carbon isotope ratio c13 declines in proportion.
eocene:4
the start of the eocene is marked by a brief period in which the concentration of the carbon isotope 13c in the atmosphere was exceptionally low in comparison with the more common isotope 12c.