Lisé-Pronovost (english)

The high-resolution rock-magnetic study reveals that 1) magnetite is the dominant magnetic mineral and carrier of a stable natural remanent magnetisation and 2) the reworked layers such as tephra material and organic-rich sediments are readily identifiable with rock-magnetic properties.

The paleomagnetic study of the sediments of Lake Laguna Potrok Aike provided a new high-resolution full-vector paleomagnetic record (inclination, declination and relative paleointensity) in a poorly documented area of the globe. This is an important contribution because our knowledge of the past variability of the geomagnetic field in the Southern Hemisphere is very limited relative to the Northern Hemisphere. The new record was compared with other lacustrine and marine records and stacks from the mid- to high-latitudes of the Southern Hemisphere, revealing consistent millennial-scale changes, the identification of the Laschamp and possibly the Mono Lake geomagnetic excursions, and a direction swing possibly associated to the Hilina Pali excursion at 20 000 cal BP. In addition, a global-scale comparison with other high-resolution records located on the opposite side of the Earth in the Northern Hemisphere and with various dipole field reference records hints at a different behaviour of the geomagnetic field in southern South America at 46 000 cal BP. Finaly, the relative paleointensity record was useful to build the radiocarbon-based PASADO-ICDP age model and magnetostratigraphy is a promising tool to better constrain the PASADO-ICDP chronology at least at the millennial-scale in specific intervals where geomagnetic changes are either global or regional.