ANTARCTIC MARINE TEMPERATURES: LATE CAMPANIAN THROUGH EARLY PALEOCENE

An oxygen isotope paleotemperature study of benthic foraminifera from the upper Campanian through lower Paleocene section at Seymour Island, near the coast of Antarctica, was done in conjunction with careful scanning electron microscope observations to monitor the state of foraminiferal preservation. The isotopic compositions of those samples which were deemed to be well preserved were the basis of the conclusion that Campanian through Paleocene high-latitude shelf waters near Antarctica had temperatures between approximately 4.5 degrees and 10.5 degrees C. Temperatures during early and middle Maastrichtian time were slightly higher than those of either the late Campanian or late Maastrichtian. The inference of temperate climatic conditions in Antarctica is in agreement with paleoclimatic conclusions drawn on the species composition of the planktonic foraminiferal assemblages and the character of the planktonic foraminifera, as well as with published conclusions based upon paleobotanical evidence. The Maastrichtian and Campanian water temperatures at Seymour Island are similar to those inferred from published isotope ratios of Pacific Late Cretaceous benthic foraminifera from low latitudes, indicating that Campanian through early Paleocene deep ocean waters, at least in the Pacific and perhaps elsewhere as well, could have formed by sinking of surface waters in polar regions.