Paleomagnetic Calibration of Radiocarbon Chronologies: Synchronization of High-Resolution Holocene Marine Sediment Records Between North Iceland and East Greenland

Under many circumstances radiocarbon chronologies are insufficient to test the phase relations among centennial scale paleoclimate records. New paleomagnetic observations indicate that the geomagnetic field undergoes rapid changes over large spatial scales. We intend to test whether paleomagnetic records constrained by radiocarbon dating can provide sufficient stratigraphic control to secure centennial scale correlations. To do this we examine high resolution carbonate, 14C and paleomagnetic records from two long IMAGES cores from proximal geographic locations, but contrasting oceanographic settings. MD99-2269 (Lat. 66.37.53 N, Long. 23.51.16 W, water depth 365 m, length 2530 cm) was taken from a trough on the North Iceland Shelf. MD99-2322 (Lat. 67.08.18 N, Long. 30.49.67 W, water depth 714 m, length 2635 cm) was collected from a trough on the East Greenland margin. Both cores are well dated with more than 15 AMS 14C dates within the Holocene in each and sedimentation rates range from 1 to 3 m/kyr. An additional tie point is provided by the Saksunarvatn tephra with an age of 10.18 cal ka. The total carbonate content is interpreted as a proxy for productivity throughout the water column and reflects the intensity of influx of North Atlantic waters to the coring sites. The carbonate records from both cores show remarkable broad similarities at the millennial scale suggesting a common response to ocean circulation changes. However, the phase relations of distinct centennial scale variability observed in both cores is uncertain. Paleomagnetic measurements made on u-channel samples from these cores provide high quality paleomagnetic secular variation records. Distinct similarities are observed between inclination and declination features with initial results indicating that refinement of radiocarbon based correlations are possible.