Micropaleontology and palynology of core PAR87A-10: A 23,000 year record of paleoenvironmental changes in the Gulf of Alaska, northeast North Pacific

Abstract

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.