Pleistocene changes in the pore concentration of a planktonic foraminiferal species from the Pacific Ocean

Abstract

A study of the pores on the test wall surfaces of the planktonic foraminiferal species Globigerina eggeri shows marked changes through time in pore concentration per unit area. In Atlantic and Caribbean core samples, the changes in pore concentration correlate with the Pleistocene climatic variations, as established both by faunal analyses and by oxygen-18 studies. High counts per unit area occur during interglacial ages, and low counts per unit area are typical of glacial ages. Pore concentration counts of Globigerina eggeri sampled from a Lamont core (V 19–47) taken in the Pacific Ocean north of Easter Island show similar changes through time, and presumably these changes relate to Pleistocene ages, as in the Atlantic and Caribbean. However there are no marked faunal variations in the core, suggesting that the Pacific Ocean remained warm throughout the Pleistocene. Evidently pore concentration in Globigerina eggeri is a response to a Pleistocene environmental change other than temperature, and may provide a key for further studies of Pleistocene chronology and rates of deposition in the Pacific Ocean.