The rapid rise in mean sea level during the last deglaciation favored the transport and availability of large volumes of sand for wind transport, allowing the formation of transgressive dunes between 8800 and 6600 years ago.

The consolidation of these dunes through natural carbonate cement, resulting from the dissolution of carbonate particles by fresh water, gave rise to sedimentary rocks called Eolianites, occasionally visible in the middle of the dune system of Armação de Pêra Bay.

These rocks are found in approximately the same location as today's dunes, highlighting the maximum transgression of mean sea level that occurred around 6000 years ago during the Holocene Climate Optimum.