Sea-level fall and coastal water cooling during the Late Holocene in Southeastern Brazil based on vermetid bioconstructions

The relative sea-level variation curve, obtained by dating and leveling vermetid shells from northern Santa Catarina State (26.3°S), presents fall trend during all the last 4.0 cal ka BP, which matches previous results based on the same kind of indicator for the Brazilian coast between 3°S and 28°S. Chemical and isotopic analyses of 50 vermetid bioconstructions from distinct localities of south-southeastern Brazilian coast indicate possible changes in the coastal water temperature. These changes may have been caused by oscillations in the strength of Brazilian Coastal Current, which carries La Plata Plume northward, being therefore responsible for the penetration of cold and less saline water masses in the study area. This is a reasonable explanation for the scarcity of vermetid biolithites around 3.4–2.6 cal ka BP and 0.5–0 cal ka BP.