PALEOINTENSITY-ASSISTED CHRONOSTRATIGRAPHY: A TOOL FOR MILLENNIAL SCALE GLOBAL CORRELATION OF LATE QUATERNARY SEDIMENTARY SEQUENCES

High resolution proxy records of relative geomagnetic paleointensity from the Labrador Sea, North Atlantic, Mediterranean, Indian Ocean, Sulu Sea and sub-Antarctic South Atlantic contain patterns of variability that are recognizable to the millennial level. A similar pattern is also observed in the inverse flux of cosmogenic isotopes preserved in the Greenland Summit and Antarctic ice cores. The similarities of these records suggest that global scale geomagnetic field variations are recorded. If so, this would provide a new means of high-resolution global correlation. However, this is difficult to confirm, as the temporal variability of the paleointensity record is greater than the precision of present stratigraphic methods beyond the radiocarbon limit. To assess the synchroneity and resolution of the paleointensity record, a millennial-scale global paleointensity-assisted chronostratigraphy (PAC) has been developed for the last 110 kyr. This stratigraphy takes advantage of high resolution regional paleoclimate stratigraphies, interhemispheric synchronization provided by trapped gas within Arctic and Antarctic ice cores, the long period variations in geomagnetic field intensity and the inverse relationship between geomagnetic field strength and the production of cosmogenic isotopes. The resulting correlation circuit places the ice core and marine records on a common GISP2 official chronology and demonstrates that Geomagnetic field intensity has common global variance at millennial time scales. Recently derived relative paleointensity records from the sub-Antarctic South Atlantic (ODP Site 1089) and the western equatorial Pacific (ODP Site 769) when compared with previous records from the sub-Arctic North Atlantic (ODP Sites 983 and 984) suggest that global millennial-scale PAC can be derived for at least the last 500 kyr.