A summary of Brunhes paleomagnetic field variability recorded in Ocean Drilling Program cores

The Ocean Drilling Program (ODP) has recovered many long sediment sequences from around the World that contain medium to high-resolution paleomagnetic records of Brunhes age. These records have provided an important new global view of geomagnetic field variability during ‘stable’ magnetic (dipole) polarity that could not be recovered by conventional terrestrial or deep-sea piston coring. The ODP paleomagnetic records of directional variability can be routinely recovered and used regionally as a very high-resolution relative chronostratigraphic tool (±200 yr resolution). ODP paleomagnetic records of Brunhes age relative paleointensity have dramatically improved our understanding of global geomagnetic field intensity. These records document the global-scale pattern of paleointensity and demonstrate its use as a high-resolution relative chronostratigraphic tool that under ideal conditions could have a precision of ±500 yr. ODP paleomagnetic records and associated oxygen isotope chronostratigraphies have also greatly improved our understanding of the number and ages of Brunhes geomagnetic field excursions, and their relationship to normal directional secular variation and paleointensity variability. Although significant progress has been made though ODP paleomagnetic studies of Brunhes-aged sediments, it is clear that more work is needed to further resolve and define the detailed global pattern of Brunhes PSV and its relationship to excursions and true polarity reversals.