Session: Glacial Climates (LGM, Last deglaciation, Ice sheet uncertainties, Glacial-interglacial cycles)
Author: Nadine Quintana Krupinski / email@example.com / Dept. of Geology, Lund University
Co-author: Karen-Luise Knudsen, Aarhus University;
Yasmin Bokhari-Friberg, Helena L. Filipsson;
Andreas Mackensen, Alfred Wegener Institute;
Jeroen Groeneveld, Bremen University;
Anne-Sophie Fanget, Aarhus University;
Marit-Solveig Seidenkrantz, Aarhus University;
Helena L. Filipsson, Helena L. Filipsson;
The Kattegat-Baltic Sea region shows evidence of strong coupling with North Atlantic climate over recent glacial-interglacial cycles, but insufficient long, continuous, high-resolution Baltic area climate records have often limited evaluating such links. New ultra-high-resolution sediment cores collected during IODP Expedition 347 allow such records to be generated, including foraminiferal geochemistry records reflecting seawater environmental changes directly adjacent to the Scandinavian Ice Sheet (SIS) during the most recent deglaciation.
We present benthic foraminiferal stable isotope (d18O and d13C) and trace element (Ba/Ca, Mn/Ca and Mg/Ca) records from IODP Site M0060 (located between Sweden and Denmark in the southern Kattegat) to constrain bottom water salinity, temperature and oxygenation changes from 18-13ka (chronology is based on 14C dating). Because of the large salinity changes (fresh to near-marine) during the past 20ka in this region, we interpret d18O as reflecting salinity changes more than temperature here, while d13C reflects ventilation, productivity, and salinity. Ba/Ca, Mn/Ca, and Mg/Ca may indicate salinity, oxygenation, and temperature variations, although these proxies are less straightforward to interpret in this setting.
Stable isotope results suggest fjord-like, poorly ventilated conditions during early Deglaciation, with three clear phases from 18-13ka : 1) an initial rapid, large freshening event; 2) subsequent slower, step-wise freshening (likely linked to the decay of the SIS); 3) more marine, ventilated, saline conditions after ~15.7ka. These events may be linked to regional and global climate changes during this period of global climate changes, and may help us evaluate the interplay between the SIS and climate in the North Atlantic and beyond.