The research carried out by the research group is based on the analysis of the magnetic properties of geological and archaeological materials, to which are added modeling studies of paleoclimates and biogeochemical cycles. Our studies include the evolution of the geomagnetic field on different time scales, marked by secular variation, excursions and reversals of polarity, plate tectonics and major instabilities related to the movement of the Earth’s axis of rotation, environmental magnetism and biomagnetism, and the functioning of the climate system and its perturbations during the history of the Earth. Our approaches are analytical, experimental and numerical.
Excursions and reversals of the geomagnetic field
Deciphering the paleomagnetic signal carried by volcanic and sedimentary rocks of different origins (marine, lacustrine, eolian) allows to trace the temporal variations in intensity and/or direction of the geomagnetic field during geological time. This signal is the only source of information on geomagnetic excursions and inversions.
Archaeomagnetism makes it possible to trace the detailed evolution of the geomagnetic field over the last millennia from the analysis of the magnetic properties of archaeological objects that were heated during their manufacture or use. In addition to studies on geomagnetic secular variation, archaeomagnetism can be used as a dating tool in archaeology.
Mineral magnetism makes it possible to study the evolution of our environment on all time scales, from past climatic variations to current anthropic disturbances. Extremely sensitive to the presence of metal oxides, it allows fine detection and precise characterisation of magnetising minerals in sediments, soils or deposited on plants.
The analysis of the remanent magnetization of magmatic or sedimentary rocks makes it possible to determine the position of the magnetic poles and to calculate the paleolatitude and orientation of the continents at a given age. Paleogeographic models are thus established by combining all the magnetic data acquired for different continents with geological observations. These models allow us to study the evolution of paleogeography over time and its interactions with surface processes such as climate and its coupling with the inner Earth such as mantle convection.
The research activities of the research group aim at understanding the interactions between the outer and inner envelopes of the Earth. They are largely based on numerical modeling of climate, biogeochemical cycles (especially carbon), continental weathering, and the cryosphere.