Environmental magnetism of Antarctic Late Pleistocene sediments and interhemispheric correlation of climatic events

Recent developments in paleomagnetism and environmental magnetism provide n ew tools for the detailed correlation of climatically induced magnetic mine ralogy changes in sedimentary sequences. Studies of these changes contribut e to the reconstruction of climate history for the glacial-interglacial cyc les of the Late Pleistocene and to the delineation of the range of natural variability for global climate during the past hundred thousands years. Her e we show that sharp coercivity minima observed in fine-grained sediments f rom the continental rise of the western Antarctic Peninsula correlate to th e major rapid cooling events of the northern Atlantic (Heinrich layers). We interpret such an environmental magnetic signal in terms of variations in deep sea diagenetic processes of sulfide formation, which reflect changes i n the input of detrital organic matter controlled by sea-ice extent. With t he inherent uncertainties in age controls, the sedimentary paleoclimatic ma rkers of the two hemispheres are almost contemporaneous, but interhemispher ic time lags or leads of the order of 1-2 kyr (such as those recently repor ted from the Greenland and Antarctic ice cores) are also compatible with th e data. (C) 2001 Elsevier Science B.V. All rights reserved.