Almost that for some sediments. Because during the Pleistocene everything was below sea level, and when the sea level rose all structures received a new carbon input and renewing the carbonate matrix. But some calcites crystallized during the fossilization does not changed the carbon matrix, and this calcite can be used for Pleistocene dating. We find these carbonates inside the mammal fossils, or even in reefs and other biological structures. you need be careful with what you are using for dating.
O problema surgiu na datações de Paleolitorais submersos a profundidades entre 5 e 20m, com idades radiocarbono de 30.000 a > 45000BP. `Parece claro que durante o Plistocénico o mar flutuou para cima e para baixo, pelo que as rochas foram sujeitas intermitentemente a carbono atmosférico e marinho, o que naturalmente deve contaminar as datações. Obrigado pelo comentário. Abração.