Integrated stratigraphic reconstruction for the last 80 kyr in a deep sector of the Sardinia Channel (Western Mediterranean)

A quantitative analysis of planktonic foraminifera, coupled with petrophysical and paleomagnetic measurements and 14C-AMS calibrations, was carried out on a deep core recovered in the Sardinia Channel (Western Mediterranean Sea), during the CIESM Sub2 survey, providing an integrated stratigraphic time-framework over the last 80 kyr. Significant changes in the quantitative distribution of planktonic foraminifera allowed the identification of several eco-bioevents useful to accurately mark the boundaries of the eco-biozones widely recognized in the Western Mediterranean records and used for large-scale correlations. Namely, 10 eco-biozones were identified based on the relative abundance of selected climate-sensitive planktonic foraminiferal species. Sixteen codified eco-bioevents were correlated with Alboran Sea planktonic foraminiferal data and several climatic global events (Sapropel S1, Younger Dryas, Greenland Isotope Interstadial 1, Greenland Isotope Stadial 2, Heinrich event H1–H6) were recognized. The eco-bioevents together with the 14C-AMS calibrations allowed us to define an accurate age model, spanning between 2 and 83 kyr. The reliability of the age model was confirmed by comparing the colour reflectance (550 nm%) data of the studied record with the astronomically tuned record from the Ionian Sea (ODP-Site 964). A mean sedimentation rate of about 7 cm/kyr included three turbidite event beds that were chronologically constrained within the relative low stand and regressive sea-level phases of MIS 4 and 3. The deep-sea sedimentary record includes a distinct tephra occurring at the base of the core that dates 78 ka cal. BP. The paleomagnetic data provide a well-defined record of the characteristic remanent magnetization that may be used to reconstruct the geomagnetic paleosecular variation for the Mediterranean back to 83 kyr.