Age determination of sediment core from the Gulf of Alaska

Micropaleontological data of core PAR87A-10 reveal that the last glacial interval, prior to 13 ka, was marked by low biogenic fluxes and poor CaCO3 preservation. Quantitative estimates of sea-surface conditions based on dinocyst assemblages suggest that cold temperatures and freezing winter conditions existed during this period. The glacial to interglacial transition, i.e., the 13–8 ka interval, was characterized by an increase in fluxes of microfossils indicating enhanced productivity in surface waters. A higher biogenic carbonate production probably resulted in better preservation of CaCO3. This interval was marked by relatively low salinity and by sea-surface temperatures increasing toward modern values. Relatively high pollen flux during the transition suggests nutrient inputs through atmospheric and/or fluvial transport from the adjacent North American continent. After 8 ka, diminished fluxes of plankton, concomitant with a decline in pollen input, are associated with decreasing nutrient supply as predominantly eastward winds became established over the North Pacific