Magnetic mineralogy of sediments and its geological implications: advances and challenges

Magnetic iron minerals are almost ubiquitous in rocks and sediments and covey important information about geological processes and past variations of the Earth’s magnetic field. The recent development of new magnetic measurement techniques at various scales, from bulk samples down to individual crystals, opens new opportunities for tackling interesting questions about planetary magnetic fields, the ancient Earth, the biogeochemical cycle, and transport processes in the atmosphere and the oceans. On the downside, magnetic characterization techniques are intrinsically non-unique and must be used in combination with micromagnetic modelling and other analytical tools. Once the magnetic fingerprint of specific magnetic mineral categories – such as silicate inclusions and authigenic magnetite in sediments – is determined, fast, non-destructuve measurements can be used to trace the processes responsible for their variation in space and time.