Relative Geomagnetic Paleointensity as a Millennial Scale Chronostratigraphic Method: Intrahemispheric Correlation

J S Stoner (Department of Geology, University of California, Davis, CA 95616 email: stoner@geology.ucdavis.edu); J E T Channell (Department of Geology, University of Florida,

Gainesville, FL 32611)

In order to understand the fundamental linkages and feedbacks in the global climate system it is necessary to accurately assess the temporal relationships between paleoclimatic proxies from different regions. For

millennial scale climate change, below the level of radiocarbon dating,

establishing these phase relationships is at best uncertain. Because geomagnetic paleointensity provides an environmentally independent

means of global correlation, an additional method for assessing these

relationships is provided. Here we use records of relative geomagnetic

field paleointensity, that are constrained by oxygen isotopic and lithologic data, in order to develop a millennial scale chronostratigraphy across the high latitude North Atlantic for last climate cycle. These records are then correlated to the Greenland (GRIP) ice core record during the period from 30-70 ka by comparing the inverse relationship between the 10. Be flux measured in the ice and geomagnetic paleointensity recorded from marine sediments. These correlations suggest that variability of the Laurentide ice sheet systematically leads the interstadial warming and is apparently in phase with most if not all the cold stadials recorded in Greenland ice core. North Atlantic sea surface temperature and NADW proxies are apparently in phase with the interstadial warming. This suggests that the temperature pattern observed in the Greenland ice cores is at least in part driven by Laurentide ice sheet variability and may, therefore, only reflect a local to regional scale record of climate during the last glacial cycle. Initial records of relative geomagnetic paleointensity from piston cores collected during the ODP Leg 177 site survey cruise from Subantarctic South Atlantic show that we can now transfer these correlations to the southern hemisphere marine sediment record and the Vostok ice core. The implication of these correlations will be discussed.