National Science Foundation and Gulf Coast Repository logos
Gulf Coast Repository

Magnetic Susceptibility Meter (Kappabridge)

Overview

Thumbnail image of Magnetic Susceptibility Meter Measurements of magnetic susceptibility and anisotropy of magnetic susceptibility (AMS) can be used to characterize the magnetic properties, texture, and petrofabric of rocks and sediments.

Kappabridge measurements are typically performed on 2 cm cubes or cylinders. The high- and low-temperature modules can only accept powdered samples.

Instrument Make and Model

AGICO MFK2 Multi-Function Kappabridge (with CS4 furnace and CS-L low temperature cryostat)

AGICO KLY-4S Kappabridge

Estimated Measurement Time

  • Instrument Preparation: 10–20 minutes
  • Sample Measurement: 1–5 minutes/sample (CS-4 and CS-L, 1–2 hrs/sample)

Principles & Analytical Capabilities

The MFK2-FA is a three frequency (976 HZ, 3904 Hz and 15616 Hz) Kappabridge fully equipped with an automatic up/down mechanism and rotator for AMS and bulk susceptibility measurements. The MFK2-FA is also equipped with the CS4 and CS-L attachments for measurements of high (up to 700 degrees C) and low temperature (down to –192 degrees C) variations of magnetic susceptibility. Instrument sensitivity is 20×10-9 SI (976 Hz, 400 A/m). The instrument is controlled by AGICO’s SAFYR7 software and AGICO’s Anisoft software is available for advanced data processing. AGICO’s Cureval program is available for processing CS-L and CS4 data.

The KLY-4S is capable of measuring AMS and bulk susceptibility of samples and is equipped with an automatic rotating specimen holder, rotating at a speed of 0.5 r.p.s inside the coil. The KLY-4S can be run via AMSspin or AGICO's Sufar software. Anisoft is available for advanced data processing. The KLY-4S operates at only one frequency (875 Hz).

From these data, the deviatoric susceptibility tensor can be computed. This tensor carries information only on anisotropic components of the specimens. To obtain the complete susceptibility tensor, one complementary measurement of bulk susceptibility must be done.

Data Generated

Data components*:

  • Sample vol (cc): volume of the specimen measured as entered by user (cm3).
  • Measurement field (A/m): the set field that the specimen was measured in.
  • Holder susceptibility: susceptibility of the holder.
  • Mean susceptibility: average of the absolute values of the principal susceptibilities, (K1 + K2 + K3) / 3.
  • Bulk susceptibility: total susceptibility of a specimen corrected for specimen volume.
  • Kmax susc: K1, the susceptibility of the maximum axis.
  • Kint susc: K2, the susceptibility of the intermediate axis.
  • Kmin susc: K3, the susceptibility of the minimum axis.
  • Kmax dec (°): declination of the maximum (K1) principal susceptibility.
  • Kmax inc (°): inclination of the maximum (K1) principal susceptibility.
  • Kint dec (°): declination of the intermediate (K2) principal susceptibility.
  • Kint inc (°): inclination of the intermediate (K2) principal susceptibility.
  • Kmin dec (°): declination of the minimum (K3) principal susceptibility.
  • Kmin inc (°): inclination of the minimum (K3) principal susceptibility.

Data files (AGICO MFK2):

  • Anisotropy of Magnetic Susceptibility (AMS)
    • Results (CSV): tabular data file containing AMS results.
    • AMS file (AMS): binary data file intended for use in the Anisoft 5 software.
    • RAN file (RAN): standard binary file for use in the Anisoft 4 software.
    • Log file (ASC): text file meant as a log file for completed measurements and not intended for further processing.
  • Bulk only
    • Results (BULK): space delimited text file in a fixed format.
  • CL-L
    • Results (CLW): fixed column width ASCII text file containing temperature and susceptibility data.
  • CS4
    • Results (CUR): fixed column width ASCII text file containing temperature and susceptibility data.

Data files (AGICO KLY-4S):

  • AMS & Bulk Results (CSV): tabular data file containing AMS and bulk susceptibility data (AMSspin software).
  • Data file (TXT): data file intended for use in the Anisoft software (Sufar software).
  • Bulk susceptibility file (KY4): bulk susceptibility file (Sufar software).
  • Anisotropy & Bulk Susceptibility Results (ASC): anisotropy and bulk susceptibility results (Sufar software).
  • RAN file (RAN): standard binary file for use in Anisoft (Sufar software).

*Users can output further statistics related to the AMS and bulk susceptibility measurements via the Anisoft software. Cureval allows the user to output further statistics and estimate Curie temperature(s) for CS-L and CS4 measurements.

Data Example

Graph of Magnetic susceptibility from Hole U1602E of IODP Expedition 395, east of the Greenland continental margin in the North Atlantic Ocean.
Stereonets: blue circles = anisotropy tensor minimum axis, green triangles = intermediate axis, red squares = maximum axis. Histograms show bulk susceptibility distribution. Bottom left: distribution of susceptibility and degree of anisotropy (Pj). Bottom right: Pj vs. shape of the anisotropy tensor (T). Magnetic susceptibility from Hole U1602E of IODP Expedition 395, east of the Greenland continental margin in the North Atlantic Ocean.1

Procedures & Manuals

AGICO MFK2 Multi-Function Kappabridge

AGICO KLY-4S Kappabridge

References

1  Parnell-Turner, R. E., Briais, A., LeVay, L. J., Cui, Y., Di Chiara, A., Dodd, J. P., Dunkley Jones, T., Dwyer, D., Eason, D. E., Friedman, S. A., Hemming, S. R., Hochmuth, K., Ibrahim, H., Jasper, C., Karatsolis, B. T., Lee, S., LeBlanc, D. E., Lindsay, M. R., McNamara, D. D., … Tian, C. Y. (2025). IODP Expedition 395 Magnetic susceptibility (Kappabridge) [Data set]. International Ocean Discovery Program. https://doi.org/10.5281/zenodo.15054123