Ultra-high sensitivity moment magnetometry of geological samples using magnetic microscopy
Name
Weiss_Ultra-high sensitivity.pdf
Size
1.71 MB
Format
Adobe PDF
Checksum (MD5)
e6a37dd2dbab0953dda85a75ae0945fe
Author(s)
Lima, Eduardo A.
Weiss, Benjamin P.
Date Issued
October 2016
Journal
Geochemistry, Geophysics, Geosystems
Publisher
American Geophysical Union (AGU)
Citation
Lima, Eduardo A. and Weiss, Benjamin P.“Ultra-High Sensitivity Moment Magnetometry of Geological Samples Using Magnetic Microscopy.” Geochemistry, Geophysics, Geosystems 17, no. 9 (September 2016): 3754–3774.
Version
Original manuscript
Abstract
Useful paleomagnetic information is expected to be recorded by samples with moments up to three orders of magnitude below the detection limit of standard superconducting rock magnetometers. Such samples are now detectable using recently developed magnetic microscopes, which map the magnetic fields above room-temperature samples with unprecedented spatial resolutions and field sensitivities. However, realizing this potential requires the development of techniques for retrieving sample moments from magnetic microscopy data. With this goal, we developed a technique for uniquely obtaining the net magnetic moment of geological samples from magnetic microscopy maps of unresolved or nearly unresolved magnetization. This technique is particularly powerful for analyzing small, weakly magnetized samples such as meteoritic chondrules and terrestrial silicate crystals like zircons. We validated this technique by applying it to field maps generated from synthetic sources and also to field maps measured using a superconducting quantum interference device (SQUID) microscope above geological samples with moments down to 10⁻¹⁵ Am². For the most magnetic rock samples, the net moments estimated from the SQUID microscope data are within error of independent moment measurements acquired using lower sensitivity standard rock magnetometers. In addition to its superior moment sensitivity, SQUID microscope net moment magnetometry also enables the identification and isolation of magnetic contamination and background sources, which is critical for improving accuracy in paleomagnetic studies of weakly magnetic samples.
MIT Department
Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences
Terms of Use
Creative Commons Attribution-Noncommercial-Share Alike
Persistent DSpace Link
DOI of Published Version
https://doi.org/10.1002/2016GC006487
