Pleistocene Climatic Record in a Pacific Ocean Core Sample

Abstract

A core sample of the bottom in the southeastern Pacific Ocean contains several layers of red clay and globigerina ooze. The highly calcareous ooze is correlated with warm-water conditions, whereas the red clay, which is low in carbonate, is correlated with cold-water conditions because the carbonate is more soluble in cold water. The core is interpreted as a record of climate. Age determinations made by W. D. Urry, using the "percentage of equilibrium method" for uranium, ionium, and radium give dates for the various layers covering a period of several hundred thousand years. The detailed interpretation of this core gives dates for the end of the Kansan glacial stage (about 700,000 years ago), for three substages of the Illinoian glacial stage (330,000; 310,000; and 274,000 years ago), for six substages of the Wisconsin glacial stage (64,000; 51,000; 37,000; 26,000; 15,000; and 11,000 years ago), and for a postglacial thermal maximum centering at 6,000 years ago. There is good correlation between the Pacific red-clay (cold-water) zones of Wisconsin age and the North Atlantic and Antarctic glacial marine zones of the same age.