New radiocarbon dates from a Holocene aeolianite, Isla Cancun, Quintana Roo, Mexico

Abstract

This paper reports on nine new radiocarbon dates from marine shells collected at various heights within a Holocene aeolianite sequence on Isla Cancun in the Yucatan Peninsula, Mexico. The ages obtained from the shells provide an improved understanding of some of the geomorphological and sedimentological processes operating during the upper mid-Holocene on Isla Cancun. Carbonate sand dunes were accreting at rates in the order of 0.28 cm yr - 1 between about 3570 and 4000 years BP. By around 4000 years BP sea levels were close to present-day shorelines evidenced by the presence of marine shells (SRR-5790) within a small wedge of beach material cut into the Cancun aeolianite at a height of +1.5 m above present-day sea levels. Cessation of dune growth is known to have occurred before 2500 years BP as shells (SRR-5793a, SRR-5793b, SRR-5794a and SRR-5794b) from a midden deposit overlying the aeolianite provide a minimum age for the end of dune activity. Dune formation appears, therefore, to be associated with the end of the postglacial transgression in sea level. At least one other sample is thought to be from a midden and the dates obtained from this site provide information on localized human occupation in the area during the Holocene between 4082 and 2349 years BP.