New constraints on the timing of sea level fluctuations during early to middle marine isotope stage 3

Abstract

To settle debate on the timing of sea level fluctuations during marine isotope stage (MIS) 3, we present records of δ18Oruber (sea level proxy) and magnetic susceptibility from the same samples within the single sediment archive (i.e., “coregistered”) of central Red Sea core GeoTü‐KL11. Core‐scanning X‐ray fluorescence and environmental magnetic data establish the suitability of magnetic susceptibility as a proxy for eolian dust content in Red Sea sediments. The eolian dust data record similar variability as Greenland δ18Oice during early to middle MIS 3, in agreement with previous observations that regional Arabian Sea climate fluctuated with a timing similar to that of Greenland climate variations. In contrast, the sea level record fluctuates with a timing similar to that of Antarctic‐style climate variations. The coregistered nature of the two records in core KL11 unambiguously reveals a distinct offset in the phase relationship between sea level and eolian dust fluctuations. The results confirm that sea level rises, indicated by shifts in Red Sea δ18Oruber to lighter values, occurred during cold episodes in Greenland during early to middle MIS 3. This indicates that the amplitudes of the reconstructed MIS 3 sea level fluctuations would not be reduced by inclusion of regional climate fluctuations in the Red Sea sea level method. Our analysis comprehensively supports our earlier conclusions of large‐amplitude sea level variations during MIS 3 with a timing that is strongly similar to Antarctic‐style climate variations.