Late Pleistocene relative geomagnetic paleointensity from the deep Labrador Sea: Regional and global correlations

Three long piston cores from the deep Labrador Sea appear to record Late Pleistocene variations of relative paleointensity of the geomagnetic field. Two cores extend at least into isotope stage 6, the other into stage 5. In addition to δ18O, δ13C and AMS 14C stratigraphies, correlation between cores is facilitated by the presence of rapidly deposited high detrital carbonate (DC) and low detrital carbonate (LDC) layers, some of which correlate to the North Atlantic Heinrich events. Hysteresis ratios and rock magnetic parameters indicate that the magnetic assemblage in the cores is pseudo-single domain magnetite. Except for deglacial intervals and DC and LDC layers, normalized remanence records show strong correlation for a range of normalizers (k,kARM and SIRM) and no correlation with bulk magnetic parameters. Paleointensity records from the three cores are consistent when only DC and LDC layers are used for correlation, suggesting that relative paleointensity can be used as a regional correlation tool. Consistent paleointensity features from the Labrador Sea, Indian Ocean and Mediterranean Sea suggest that the sediments are recording dipole field variations. Although the composite record from two Labrador Sea cores is strongly correlated to a composite of the Mediterranean/Indian Ocean records, the chronologies are inconsistent, indicating apparent discrepancies in the isotopic and AMS 14C chronologies used in the Mediterranean/Indian Ocean and Labrador Sea, respectively.