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Gulf Coast Repository

Section Half Multisensor Logger (SHMSL)

Overview

Thumbnail image of Section Half Multisensor Logger Measurements of magnetic susceptibility and color reflectance provide basic physical properties and paleomagnetic data, which can be useful in the identification of lithologic units and stratigraphic correlation. The Section Half Multisensor Logger (SHMSL) is also equipped with a laser rangefinder for determining surface height variations on the split core surface.

Maximum core diameter: 15 cm (o.d.)
Maximum core length: 160 cm

Instrument Make and Model

Custom-built system.

Estimated Measurement Time

  • Sample Preparation: ~5 minutes
  • Sample Time: Scan time estimates are based on a 1.5 meter core length.
Estimated time based on measurement resolution.
Resolution Scan Time
0.2 cm 120 mins
0.5 cm 45 mins
1.0 cm 25 mins
2.0 cm 8 mins
2.5 cm 7 mins

Measurement Resolution

  • Highest resolution: 1 cm (color reflectance); 0.2 cm (magnetic susceptibility)
  • Most commonly used resolution: 2-2.5 cm

Principles & Analytical Capabilities

Reflectance spectroscopy and colorimetry (RSC) data are acquired using an Ocean Insight QE-Pro spectrophotometer which records 2 nm-resolution data in the visible range. Spectral data are transformed to X,Y,Z tristumulus values, which can be related to color in the CIE cylindrical coordinate system (L* a* b*) where L* is luminosity (total light reflected), a* is redness (blue + green), and b* is yellowness (red + green).

Magnetic susceptibility point (MSP) data are acquired using a Bartington MS2K point sensor, which has a 1 cm recording area and a small pickup area. Because the sensor is in contact with a section half, the MSP data on the SHMSL is calibrated to SI magnetic susceptibility units, assuming the sample is a flat surface and has a depth greater than 10 mm.

The laser rangefinder records the surface height of the core section. Its primary function is to allow the instrument to find flat places to land the MSP and RSC sensors, but it also records a log of the surface height.

Data Generated

Data components:

  • Color reflectance
    • Reflectance L*: lightness of the sample expressed in the CIELAB color space.
    • Reflectance a*: position of the color on the axis between red/magenta and green (negative = greater green character) in the CIELAB color space.
    • Reflectance b*: Position of the color on the axis between yellow and blue (negative = greater blue character) in the CIELAB color space.
  • Magnetic susceptibility
    • Magnetic susceptibility (SI): magnetic susceptibility of the sample, volume-corrected as follows: magnetic susceptibility is reported in calibrated SI values, assuming the sample is a flat surface and has a depth greater than 10 mm.
  • Surface Variation
    • Laser to surface distance (cm): the distance between the laser and the surface of the core; can be used to evaluate variability in core thickness.

Data files:

  • Color reflectance calculated (CSV): tabular file of calculated colorimetric results expressed in a variety of color spaces (e.g. - L*, a*, b*). These values are the most commonly used product of the color measurement.
  • Color reflectance normalized (CSV): tabular file of percent color reflectance spectra. Normalized spectra are calculated from the raw, white standard, and dark standard spectra.
  • Color reflectance dark (CSV): tabular file of the RSC dark calibration measurement.
  • Color reflectance white (CSV): tabular file of the RSC white calibration measurement.
  • Magnetic susceptibility (CSV): tabular file of magnetic susceptibility (point) results.
  • Sample length (CSV): tabular file containing the length of the core section as determined by the laser profile sensor.

Raw files:

  • Color reflectance raw (CSV): tabular file of raw sample color reflectance spectra.
  • RSC (instrument file): data file containing RSC reduced data and metadata.
  • MSPOINT (instrument file): data file containing MSPOINT data and metadata.
  • PROFILE (instrument file): data file containing the length of the core section as determined by the laser profile sensor.
  • PROFILE (CSV): tabular file of the uncorrected range to the surface from the laser by offset at 0.1 mm resolution and the measurement metadata.
  • Magnetic susceptibility raw (CSV): Data file presenting magnetic susceptibility (point) test results in tabular format.

Configuration files:

  • Config.zip (ZIP): each instrument (RSC, MSP, and laser profile) has its own zip file containing SHMSL and instrument configuration information. Some of these files are in common between the three individual measurements.

Data Example

Graph of variability of color reflectance and magnetic susceptibility point data across layers of alternating light greenish gray silt with gypsum and reddish brown oxide rich silt.
Variability of color reflectance and magnetic susceptibility point data across layers of alternating light greenish gray silt with gypsum and reddish brown oxide rich silt. Hole U1613A of IODP Expedition 402 in the Tyrrhenian Sea.1, 2, 3

Procedures & Manuals

References

1  Malinverno, A., Zitellini, N., Estes, E. R., Abe, N., Akizawa, N., Bickert, M., Cunningham, E. H., Di Stefano, A., Filina, I. Y., Fu, Q., Gontharet, S. B. L., Kearns, L. E., Koorapati, R. K., Lei, C., Loreto, M. F., Magri, L., Menapace, W., Morishita, T., Pandey, A., … Zhao, X. (2025). IODP Expedition 402 Magnetic susceptibility (point or contact system) [Data set]. International Ocean Discovery Program. https://doi.org/10.5281/zenodo.15238645

2  Malinverno, A., Zitellini, N., Estes, E. R., Abe, N., Akizawa, N., Bickert, M., Cunningham, E. H., Di Stefano, A., Filina, I. Y., Fu, Q., Gontharet, S. B. L., Kearns, L. E., Koorapati, R. K., Lei, C., Loreto, M. F., Magri, L., Menapace, W., Morishita, T., Pandey, A., … Zhao, X. (2025). IODP Expedition 402 Color reflectance [Data set]. International Ocean Discovery Program. https://doi.org/10.5281/zenodo.15238671

3  Malinverno, A., Zitellini, N., Estes, E. R., Abe, N., Akizawa, N., Bickert, M., Cunningham, E. H., Di Stefano, A., Filina, I. Y., Fu, Q., Gontharet, S. B. L., Kearns, L. E., Koorapati, R. K., Lei, C., Loreto, M. F., Magri, L., Menapace, W., Morishita, T., Pandey, A., … Zhao, X. (2025). IODP Expedition 402 Section-half images [Data set]. International Ocean Discovery Program. https://doi.org/10.5281/zenodo.15238608