Geomagnetic paleointensity and environmental record from Labrador Sea core MD95-2024: global marine sediment and ice core chronostratigraphy for the last 110 kyr

Piston core MD95-2024 from the Labrador Rise provides a continuous record of rapidly deposited detrital layers denoting Laurentide ice sheet (LIS) instability. The core also provides a high-resolution record of geomagnetic paleointensity, that is consistent with, but at higher temporal resolution than previous Labrador Sea records. Correlation to the Greenland Summit ice cores (GRIP/GISP2) is achieved by assuming that Labrador Sea detrital layers correspond to cold stadials in the ice cores. This allows a GISP2 official chronology to be placed on MD95-2024 which is consistent with the inverse correlation between paleointensity and the flux of cosmogenic isotopes (Be-10 and Cl-36) in Greenland ice cores. Synchronous millennial scale variability observed from the MD95-2024 paleointensity record and a North Atlantic paleointensity stack (NAPIS-75) [C. Laj et al., Philos. Trans. R. Sec. Ser. A 358 (2000) 1009-1025], independently placed on the GISP2 official chronology [IC. Kissel et al., Earth Planet. Sci. Lett. 171 (1999) 489-502], further support the sediment to ice core correlation. High-resolution paleointensity and oxygen isotope records from the North Atlantic, Mediterranean, Somali Basin, sub-Antarctic South Atlantic and the relative flux of Be-10 in Vostok (Antarctic) ice core are used to derive a common chronostratigraphy that neither violates the regional (millennial) or global (orbital) scale environmental stratigraphics. The resulting correlation circuit places the ice core and marine records on a common GISP2 official chronology, which indicates discrepancies as high as 5 kyr between the GISP2 and SPECMAP time scales. It further demonstrates that LIS instabilities in the Hudson Strait area are synchronous with cooling in the Greenland Summit ice cores and warming in the sub-Antarctic South Atlantic and in the Vostok ice core. Geomagnetic field intensity shows common global variance at millennial time scales which, in view of the out-of-phase interhemispheric climate variability, cannot be attributed to climatic contamination of the paleointensity records. (C) 2000 Elsevier Science B.V. Al rights reserved.