Seven marine cores from the east coast of Baffin Island were examined for variations in diatom content. The cores have good age control and were used for Holocene paleoceanographic reconstruction. A diatom barren zone or a zone of much reduced diatom productivity is evident some time during the early to middle Holocene. This zone ends earlier in the southern area than farther north. The changes in diatom productivity may be caused by changing oceanographic variables such as sea ice extent and the presence of a meltwater cap during deglaciation. Light isotope 18O events ("meltwater spikes") generally coincide with barren or reduced productivity zones in the cores from the middle and southern part of the shelf and from Jones Sound, suggesting a general surficial cooling of the fjord and ocean water. If diatom productivity was depressed because of a meltwater cap over the core sites with increasing sea ice extent, the theory of a general "marine optimum" in all of Baffin Bay and Davis Strait from 8000 to 6000 BP may have to be modified.

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