The Cariaco Basin, off the coast of Venezuela, acts as a depocenter for sediments of marine and terrestrial origin. The high rate of sedimentation in the basin and the anoxic conditions create a favorable setting for studying short-term paleoenvironmental changes. Pollen analyses of fifty-six samples from core MD03-2620 collected in the basin and spanning the Younger Dryas and Last Glacial/Holocene transition, provide vital information for reconstruction of vegetation dynamic, paleoclimate and sea-level oscillations on the northern margins of South America. Dynamic changes in environmental conditions are clearly reflected in the ratio of arboreal to non-arboreal pollen. The maximum forest vegetation is found at the end of the Last Glacial. Subsequent oscillations in the arboreal to non-arboreal pollen ratio probably represent the Bolling/Allerod. The minimum in forest vegetation occurs at the Younger Dryas, which is followed by a gradual increase in arboreal forms up to Holocene time. Variations in both the diversity of species and the pollen concentration correlate well with the marine oxygen isotope records.

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