Supersivor: Claude Hillaire-Marcel
Co-supersivor: Anne de Vernal
Starting date: September 2017
Research topic: The goal of our study is to give constraints on the chronostratigraphy of central Arctic Ocean sediments due to a lack of consensus on the subject. Measuring the excesses of thorium 230 (230Thxs) can give uncontestable age constraints as has been demonstrated in Hillaire-Marcel et al.(2017). Cores from the Lomonosov ridge will be analysed to extend the stratigraphy based on the 230Thxs age constraints.
Progress update: Core PS87-055-1 was examined for: grain size, mineralogy, geochemistry (Corg, Cinorg), and isotopes (210Pb, 238U, 234U, 232Th, 230Th). The preliminary results on core PS87-055-1 don't show a gradual decrease in 230Thxs. There is an excess of 230Th all along the first 25cm, with two spikes at depths of 5-10cm and 20-25cm. The portion of the core that was analysed is thus younger than 300 ka, and the 230Thxs spikes remain to be explained.