Late Quaternary sedimentation patterns on the Meriadzek Terrace, Bay of Biscay (ESSCAMP 02 core: 47°N 9°W)

Abstract

Foraminiferal assemblage changes, size and mineralogy of lithic grains, oxygen isotopes, CaCO 3, and dolomite content were studied along a 9-m-long core from the Meriadzek Terrace to gain insight into climate, productivity, and sediment source changes at this part of the Northeast Atlantic margin during the late Quaternary. An age model has been generated on the basis of radiocarbon dating, downcore foraminiferal assemblages, and δ 18O values. High sedimentation rates at this site allow very detailed records for the last glacial period down to late isotopic stage 3. Sea surface temperature (SST) inferred from the foraminiferal assemblages, δ 18O curve, and the temperature estimation by the SIMMAX analog technique reveal three distinctive periods during isotopic stage 2, with late stage 2 (15.3–13.4 ka) being the coldest period of the last 26 ka. A northward retreat of the polar front at 13.4 ka based on the SST record coincides with the strongest peak of primary productivity as indicated by the foraminiferal fluxes. Levels rich in large lithic grains (LLG) interpreted as ice-rafted debris (IRD) correspond to periods of low SST and are coeval with Heinrich layers 1, 2 and 3. However, the hematite-stained quartz found in the detrital fraction and the scarce dolomite and detrital carbonate content in our core point to an Iceland and/or Fenno-Scandian rather than a Laurentian or Greenland origin of this material.