Malacological Study of the Momuna (Iguape, Brazil) Shell-middens and their Paleoenvironmental Significance

Abstract

The shell-middens present in the Iguape (São Paulo State) coastal plain are situated at different distances from thepresent shoreline. In general, the more external shell-middens, which show a dominance of Anomalocardia brasilianashells, give younger ages than the more internal shell-middens, which correspond to the Holocene most important lagoonexpansion occurred between 5 and 6 ky B.P., and are commonly composed of Crassostrea brasiliana shells. Moreover,it was observed that the δ13C(PDB) ratios of the shells change according to the geographic location of the shell-middens, asa function of RSL (Relative Sea-Level) fluctuations with time. In this paper, the malacofauna of the shell-middens of theMomuna 1 and 2, both located at the homonymous village (Iguape, São Paulo State, Brazil), on the Cananeia Formation(120 ky B.P.), was studied.

Keywords

• Shell-middens
• Lagoon expansion
• Relative Sea-Level (RSL)