title: Microbially assisted recording of the Earth's magnetic field in sediment.
abstract: Sediments continuously record variations of the Earth's magnetic field and thus provide an important archive for studying the geodynamo. The recording process occurs as magnetic grains partially align with the geomagnetic field during and after sediment deposition, generating a depositional remanent magnetization (DRM) or post-DRM (PDRM). (P)DRM acquisition mechanisms have been investigated for over 50 years, yet many aspects remain unclear. A key issue concerns the controversial role of bioturbation, that is, the mechanical disturbance of sediment by benthic organisms, during PDRM acquisition. A recent theory on bioturbation-driven PDRM appears to solve many inconsistencies between laboratory experiments and palaeomagnetic records, yet it lacks experimental proof. Here we fill this gap by documenting the important role of bioturbation-induced rotational diffusion for (P)DRM acquisition, including the control exerted on the recorded inclination and intensity, as determined by the equilibrium between aligning and perturbing torques acting on magnetic particles.
authors: Department of Earth and Environmental Sciences, Ludwig-Maximilians University, Munich 80333, Germany.
authors: Xiangyu
authors: X
authors: Zhao
authors: Central Institute of Meteorology and Geodynamics (ZAMG), Division Data, Methods and Models, Vienna 1190, Austria.
authors: Ramon
authors: R
authors: Egli
authors: Department of Earth and Environmental Sciences, Ludwig-Maximilians University, Munich 80333, Germany.
authors: Stuart A
authors: SA
authors: Gilder
authors: Department of Earth and Environmental Sciences, Ludwig-Maximilians University, Munich 80333, Germany.
authors: Sebastian
authors: S
authors: Müller
mesh_terms: D058491:Bacterial Load; D018534:Earth, Planet; D019015:Geologic Sediments / Q000382:microbiology*; D060526:Magnetic Fields; D012399:Rotation; D019415:Torque