South Atlantic and North Atlantic geomagnetic paleointensity stacks (0-80 ka): implications for inter-hemispheric correlation

Recent coring of high-deposition-rate Atlantic sediments has led to the development of North Atlantic (NAPIS) and South Atlantic (SAPIS) geomagnetic paleointensity stacks. The SAPIS stack comprises five records from the sub-Antarctic South Atlantic (41-47degreesS, 6-10degreesE). Four are from piston cores collected during the Ocean Drilling Program (ODP) Leg 177 site survey cruise (Earth Planet. Sci. Lett. 175 (2000) 145). The other is ODP Site 1089 (Leg 177) (J. Geophys. Res., 2001, submitted for publication). All but one (4-PC03) of the SAPIS cores have oxygen isotope records which are used in conjunction with lithologic and geomagnetic variability to derive an optimized correlation to Site 1089. The Site 1089 age model is derived by mapping the benthic and planktic isotope data to those from nearby core RC11-83 which has 14 calibrated radiocarbon ages in the 11-41 ka interval. Below this level, the chronology is derived by matching the Site 1089 benthic oxygen isotope data to the SPECMAP stack. The NAPIS stack comprises six records from a wide area of the North Atlantic (Philos. Trans. R. Soc. Ser. A 358 (2000) 1009). Correlation between cores was based on marine isotopic stage boundaries, augmented by millennial-scale features (Heinrich events and fluctuations in concentration-dependent magnetic parameters). NAPIS was placed on the GISP2 chronology, using the marine to ice-core oxygen isotope correlation proposed by Voelker et al. (Radiocarbon 40 (1998) 517) for one of the NAPIS cores. In the resulting age model, the Laschamp Event, recorded in five of six cores, falls in a very narrow (< 1 kyr) age range and coincides with the Be-10 and Cl-36 peak measured in the ice cores. Comparison of the two stacks, placed on their own independent age models, indicates that common millennial scale paleointensity features are preserved. Although more work is needed to define the "true" global content of the paleointensity record as well as the precise age of many features, it is readily apparent that paleointensity can provide a global correlation tool at a resolution unattainable from isotope data alone. (C) 2002 Published by Elsevier Science Ltd.