Cross-latitudinal climate teleconnections during the last interglacial

Abstract:

A series of climate interruptions have been noted around the last warm period (MIS5e). Some of these are particularly conspicuous and occurred during both the deglacial as well as the glacial onset. These events are often associated with iceberg/meltwater charges into the subpolar/polar North Atlantic. A new multiproxy analysis using planktic foraminiferal abundances and SSTs, abundances of alkenone compounds and alkenone SSTs, and stable O/C isotope measurements was performed for Site 975 (Balearic Basin; Western Mediterranean). Samples covered the time from late MIS 6 to early MIS 5d with emphasis on the climate progression of the last interglacial period. A number of abrupt climate changes related to alternating influence of northern nutrient rich and southern oligotrophic water masses was revealed. Among the climate fluctuations, North Atlantic events Heinrich 11 as well as cooling events C27 – C23 could all be identified. However, in comparison to the eastern North Atlantic mid-latitude region, at Site 975 events C27 and C26 seem to be significantly more pronounced. This fact, along with evidence of a two-phase climate optimum with the SST maximum reached during its later phase, implies close similarity in climate dynamics between the Western Mediterranean and the polar Nordic Seas. It is therefore proposed that the postglacial marine development in the Nordic Seas – for instance, due to presence of winter sea ice – had a strong impact on the western Mediterranean climate via meridional atmospheric circulation patterns and temperature gradients.