Holocene climate and environmental change inferred from multiproxy data from Cenote Jennifer, Cayo Coco, Cuba

English Abstract:

There is a limited understanding of Holocene climate variability in the insular Caribbean, in part because of a lack of suitable lakes from which to collect long sedimentary sequences. The purpose of this project is to help to fill this gap by providing high-resolution proxy data from a sediment core collected on Cayo Coco, north-central Cuba. The 300 cm long core was dated using Pb-210 and 15 AMS radiocarbon dates on twigs and other macrofossils. These results indicate that organic sedimentation began approximately 9000 calendar years ago (yielding an average sedimentation rate of 0.02 cm/year) when the basin filled with water as relative sea level began to rise. Limnological data show very low values of dissolved oxygen at the base of the water column; these anoxic conditions have preserved an excellent record of mm- to cm-scale laminations throughout much of the core. The origin of these laminations may be related to precipitation or other high energy events (e.g., storms or hurricanes) as well as past hydrologic changes at the site. Preliminary pollen analysis at lower depths in the core show the establishment of wetland vegetation at ~ 7300 cal yr BP, often dominated by one or two species. By ~ 500 cal yr BP the dry evergreen forest and mangroves present today had already been established. Further pollen analysis will be done to identify vegetational and environmental trends and to examine to what extent events such as the Little Ice Age, the Medieval Warm Period, and severe droughts recorded in other Caribbean locations are detectable in the pollen record.
The core represents one of the only Holocene-length sedimentary records for the insular Caribbean and will add to our knowledge of long-term climate changes in the region.