ABSTRACT

Holocene molluscan deposits in NE Buenos Aires Province were sampled in 27 localities (139 samples), and a quantitative palaeoecological study was performed for the first time. Several biofacies and faunal associations were determined using cluster analysis. Salinity is probably the most important environmental factor controlling composition and distribution of the biofacies. The biofacies belong to an estuarine environment with a salinity range fluctuating between mixo and polyhaline gradients. Salinity controlled sequences of sub-biofacies occur in the N and S regions of the study area.

Compositional differences between the studied fauna and that living in the adjacent coasts of Buenos Aires Province are probably related to sea-level changes and coastal physiography.