The CLIMAP maps of ice-age sea-surface temperatures, glacier ice, and albedo, created nearly 20 years ago, have been questioned especially in the tropics and subtropics. Although some regional updates have been made to the Last Glacial Maximum-Sea Surface Temperatures (LGM SST) maps, no systematic, internally-consistent, multi-proxy reconstruction has yet been made of tropical and subtropical thermal structure of the ice age oceans. Such a reconstruction is critical to the goals of the international PMIP (Paleoclimate Modeling Intercomparison Project) and EPILOG (Environmental Processes of the Ice-Age: Land, Ocean, and Glaciers) programs. This award supports a study to reconsider glacial maximum environments of the low-latitude Atlantic and eastern Pacific Oceans, to test a hypothesis that CLIMAP's reconstruction was in error in these regions and to improve LGM boundary condition estimates for modeling studies. Work will focus on (1) an incorrect assumption that modern (core-top) faunal assemblages were representatives of past ice-age) assemblage groupings, and (2) the failure to consider linkages between biological productivity and temperature in the biological response of the plankton. Data and insight gained in the last 20 years warrants a new systematic look at Last Glacial Maximum (LGM). This study will provide (1) a high quality data set of oceanic thermal estimates, (2) insight into the processes that drive oceanic thermal changes, and (3) model predictions that can be compared to other sources LGM environmental data and models.
