Between Geomagnetism and Archaeology: What Ferromagnetic Minerals Tell Us About Variations in the Earth’s Magnetic Field

The magnetic properties of certain natural and anthropogenic archives (sediments, volcanic rocks, and archaeological baked-clay materials) provide valuable information on past variations in the Earth’s magnetic field over different timescales. They also contribute to the reconstruction of past environments and climates. After a brief introduction to the research topics and facilities of the “Climate and Magnetism” (CliMag) team at LSCE, the seminar will focus on the study of secular variation in the geomagnetic field over the last few millennia. This variation is primarily reconstructed by measuring the thermoremanent magnetization acquired by archaeological baked-clay materials (kilns, hearths, pottery, and bricks) during their last high-temperature firing. Once established, the secular variation of the geomagnetic field can be used as a geochronological tool. We will present our work on Western Europe between 1500 and 0 BCE and on sub-Saharan Africa, highlighting its implications for both geomagnetism and archaeology.