Determining Individual Particle Magnetizations in Assemblages of Micrograins

Determining Individual Particle Magnetizations in Assemblages of Micrograins

de Groot, L.V. (Universiteit Utrecht)
Fabian, Karl (Geological Survey of Norway)
Béguin, Annemarieke (Universiteit Utrecht)
Reith, Pim (University of Twente)
Barnhoorn, A. (TU Delft Applied Geophysics and Petrophysics)
Hilgenkamp, Hans (University of Twente)

2018

Obtaining reliable information from even the most challenging paleomagnetic recorders, such as the oldest igneous rocks and meteorites, is paramount to open new windows into Earth's history. Currently, such information is acquired by simultaneously sensing millions of particles in small samples or single crystals using superconducting quantum interference device magnetometers. The obtained rock-magnetic signal is a statistical ensemble of grains potentially differing in reliability as paleomagnetic recorder due to variations in physical dimensions, chemistry, and magnetic behavior. Here we go beyond bulk magnetic measurements and combine computed tomography and scanning magnetometry to uniquely invert for the magnetic moments of individual grains. This enables us to select and consider contributions of subsets of grains as a function of particle-specific selection criteria and avoid contributions that arise from particles that are altered or contain unreliable magnetic carriers. This new, nondestructive, method unlocks information from complex paleomagnetic recorders that until now goes obscured.

Rock magnetism
Rock physics

http://resolver.tudelft.nl/uuid:ffe14bc6-67b0-46f1-bb3b-4196f02e4831

https://doi.org/10.1002/2017GL076634

0094-8276

Geophysical Research Letters, 45 (7), 2995-3000

Institutional Repository

journal article

© 2018 L.V. de Groot, Karl Fabian, Annemarieke Béguin, Pim Reith, A. Barnhoorn, Hans Hilgenkamp