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Caribbean hydrological variability during the Holocene as reconstructed from crater lakes on the island of Grenada

Abstract:

Contemporary precipitation patterns in the Caribbean region are spatially variable, and the small number of Holocene paleoclimatic records may not adequately capture patterns of variation in the past. The hydrological history of Grenada was inferred from paleolimnological analyses of sediment cores from two crater lakes on the island. The basins were formed by volcanic activity some time during the Last Termination, but were dry between ca 13000 and ca 7200cal a BP. After filling, the lakes were initially very shallow, and sedimentation was interrupted by a hiatus ca 6300-5500cal a BP, followed by deposition of a thick tephra in both sites. After 5500cal a BP, lake level shows considerable multi-centennial variability, superimposed upon a long-term trend of generally higher lake level after 3200cal a BP. The pattern of lake-level variation in Grenada shows some similarity with other Caribbean paleoclimatic records in terms of the timing of transitions, but differs from several classic studies in the sign of inferred precipitation change. The differences among records may reflect spatially variable precipitation patterns in the past in response to the position of the Intertropical Convergence Zone and to sea surface temperature influences on the trade winds and Caribbean low-level jet. © 2011 John Wiley & Sons, Ltd.