Berger 9301438 The authors propose to study periods of known or suspected rapid climate change at an annual resolution, using laminated sediments from Santa Barbara Basin off Southern California. Times of interest include the "Medieval Warm Period" (950-1350 A.D.), the climatic optimum (5000 and 8000 years B.P.), the deglacial period and the full glacial. Cores will be scanned by Xradiography to set up a chronology and identify levels of interest; for each level a section representing a few decades will then be sampled with annual resolution. The occurrence of El Ni~io intervals, intensity of upwelling and levels of primary production, and regional precipitation will be inferred from temperature-dependent alkenones, stable carbon isotopes and nitrogen, abundance and taxonomy of phytoplankton fossils, and varve thickness.
