The "ChronoMag" team researches are principally focused on rapid climatic changes and in particular on interhemispheric and interbasin climatic phasing. They are conducted in close collaboration with other teams of the LSCE, in the frame of national and European projects. Our team is strongly involved in organizing, managing and conducting oceanographic cruises devoted to sediment coring, with the French research vessel Marion Dufresne (from the Institut Polaire). We have also participated to Integrated Ocean Drilling Program (IODP) cruises.
Main research axes are:
i) Establish a chronology for the last hundred thousand of years, independently from climatic proxies by integrating a high resolution curve of past geomagnetic intensity changes and potassium/argon et argon/argon radio-isotopic ages of volcanic sequences and ash layers imbedded in sediment series. Precise knowledge of geomagnetic field variations allows correlations between sediments and between sediments and ice via cosmogenic isotopes abundance, and contribute to a better understanding of the radiocarbon cycle.
ii) Studies of the magnetic phase and of the sediment granulometry, in order to trace the variations of the marine currents and also changes in the sources of the deposited grains in various oceanographic contexts (thermohaline circulation changes, past monsoon evolution. Similar studies are also conducted by our team in lacustrine and fluviatil domains
iii) Understanding how the magnetic remanence is acquired by sediments, which requires investigations of physical and chemical properties of the different magnetic minerals present in the sediment (some small grains may largely contribute to the magnetic signal, even with a little abundance)
iv) Reconstruction of the evolution of large volcanic units (Canaries, Hawaii, Aeolian islands, Iceland) using radiometric K/Ar and Ar/Ar dating. Research activities in this topic include studies devoted to calibration of samples used as standard used in these datations and therefore in calibration of the geological age scale.
last update : 05-30-2011 (132)