RECONSTRUCTION OF CARIBBEAN CLIMATE CHANGE OVER THE PAST 10,500 YEARS

SEDIMENT cores from low-latitude lakes provide some of the best records of tropical climate change since the late Pleistocene. Here we report a high-resolution reconstruction of Caribbean climate based on O-18/O-16 ratios in ostracod shells from Lake Miragoane, Haiti. Our results show that the climate was dry and the lake level low during the latter part of the Younger Dryas chronozone (10.5-10 kyr BP), but that water level in the lake rose at the end of the last deglaciation (approximately 10-7 kyr BP), reflecting the wetter conditions of the early Holocene which persisted for nearly 4,000 years. Lake level declined at approximately 3.2 kyr BP with the onset of a drier climate which generally prevailed throughout the late Holocene. These long-term changes in Caribbean climate are generally similar to those found for Africa over the same period, and can be largely explained by orbitally induced (Milankovitch) variations in seasonal insolation which modified the intensity of the annual cycle. Superimposed on the orbitally forced climate trends are more abrupt climate events that result from complex, nonlinear interactions in the ocean-atmosphere system. The interpretation of Antillean biogeography and the development of Caribbean and Mesoamerican culture must be considered in the context of such shifts in climate.