Late Pleistocene-Holocene planktic foraminifera of the western equatorial Pacific

Planktic foraminiferal assemblages were studied qualitatively and quantitatively in 13 samples obtained at 3 cm intervals throughout the uppermost Pleistocene‐Holocene deposits of Box core 123 (Eurydice Expedition, western equatorial Pacific Ocean). Absolute ages of these samples have previously been determined by the 14C method; the lowest sample dated from approximately 16,000 B.P. A curve based on the ratio between specimens of warm and warm‐temperate vs. cold and cold‐temperate water assemblages suggests that two temperature drops occurred during this time‐span: at 11,OOO B.P. and around 4,000–2,OOO B.P. The former drop corresponds to the onset of the Younger Dryas cooling. An unexpectedly high dominance of Globigerinita clarkei (up to 60%, on the average 48.5%) was observed throughout the entire core. Isolated, small‐sized and poorly developed specimens of typical cold water foraminifera were present in the materials investigated; their origin is most probably due to advection via equatorward subsurface currents.