GeoTek Multi-Sensor Core Logger Facility

Science Center Objects

The GeoTek Facility uses a state-of-the-art GeoTek Multi-Sensor Core Logger (MSCL) to collect automated, non-destructive geophysical and geochemical measurements on soft sediment and rock cores and discrete subsamples. The GeoTek MSCL has a horizontal track with a motorized pusher to guide cores and sample mounts through multiple sensors, which collect data simultaneously. The GeoTek MSCL is also capable of collecting high-resolution line-scan images for sample analysis and archival. The facility is available to USGS and non-USGS researchers. For more information, please contact Jessica Rodysill at


Line-scan imaging: The GeoTek MSCL has a GeoScan V Linescan Imaging system that is capable of collecting line-scan images at resolutions of 25 µm, 50 µm, and 100 µm pixel widths.  The line-scan technology produces high quality images that do not exhibit “stitching” effects.  Polarizing filters on the camera lens and the LED lamp lights reduce glare effects for wet samples.  RGB color values are collected with each image.

Gamma density: A 137Cs gamma ray source and gamma detector are mounted on the GeoTek MSCL for measuring bulk density based on gamma attenuation through core samples.  Gamma density is typically measured on whole cores in a liner or unlined whole rock cores every 0.5 or 1 cm and calibrated to grams per cubic centimeter using an aluminum calibration piece mounted inside a scrap of the same liner material that the cores are stored in (if applicable).  Gamma density can be measured on split cores under special circumstances.

Magnetic Susceptibility: A 100 mm diameter Bartington MS2C loop sensor and an MS2E point sensor are used to collect magnetic susceptibility data on whole and split cores, respectively.  Magnetic susceptibility measurements are typically collected every 0.5 or 1 cm with 1 or 10 second dwell times. 

P-wave measurement system: The GeoTek MSCL has two acoustic rolling transducers for measuring p-wave velocity on whole or split lined cores and two piston transducers for measuring p-wave velocity on whole or split bare rock cores.  P-wave velocities are typically measured on whole cores every 0.5 or 1 cm.

Color spectrophotometry: Precise color measurements are collected on split core surfaces and subsamples using a Konica Minolta CM-700d spectrophotometer.  Typical color measurements are collected every 0.5 to 1 cm, and data output includes percent reflectance at wavelengths between 400 and 700 nm, RGB values, L*a*b* values, XYZ values, and Munsell color values.