The significance of 14 C dating on the reconstruction of paleo-sea level and in the quaternary barrier evolution in the State of Parana, Brazil

The C-14 datations are one of the main tools to reconstruct paleo-seal level and to understand the Quaternary barriers evolution. Thi paper discuss the significant of 33 14 C date dated samples on paleo-sea level reconstruction and in the interpretation of Upper Pleistocene and Holocene barrier evolution in the State of Parana. We have concluded that: it is unlikely that humic and fulvic acids are influencing the dating of wood samples from sediments impregnated with organic matter; in situ reef remains, composed mainly of vermetid tubes of Petaloconchus (Macrophragma) varians, are the most precise and reliable paleo-sea level indicators found in the coast of Parana, showing a margin of error around ± 1,0 m; the height of the shell banks, composed mainly of Anamalocardia brasiliana and containing abundant shells in live position, indicates a paleo-sea level equal or higher than the mean sea level during the organisms lifetime; interpretation of paleo-sea level through composed indicators provide only maximum ages because the dated-sample could be older than the sedimentary structure used determine paleo-sea level; the marine paleo-sea level indicators suggest that, during the late Pleistocene, the sea reached > 4.0 m above present sea level; dating of vermetid tubes indicates that the maximum Holocene sea level on the Parana coast occurred between 5370 and 4630 years B.P.; the Holocene high maximum was about 3.5-3.6 ± 1.0 m; after the maximum, the sea level gradually dropped, but the possibility of the occurrence of decimeter oscillations is not rejected; the paleo-seal level inferred from mollusk banks, mainly composed of Anomalocardia brasiliana, and composed indicators, such as sedimentary structures associated with transported shells and wood fragment, agree with paleo-sea levels inferred from vermetid tubes on the Parana coast. (author)