Split-Core Logging

On-site split core processing
Many observations and analyses can only be made on split core surfaces, and if these measurements are required in a timely fashion, core must be split on site. However, once core is split, it begins to degrade. Immediate core imaging and colour measurement preserves a record of the visual appearance of the fresh core, and rapid magnetic susceptibility measurement guards against loss of data due to oxidation effects. Geotek provides a fully-featured laboratory container with facilities for core splitting, imaging, and automated split-core measurements.

Quality split core
Core splitting is a standard operation, generally performed with non-standard equipment. The quality of the split core affects subsequent image data and other measurements made on the split core surface. The Geotek core splitter is designed to enable fine adjustments to be made that in turn enable the best possible split core surfaces, including reproducible thicknesses, with further analysis in mind. The core from the Geotek core splitter is ideal for high-resolution imaging with the Geotek MSCL-CIS linescan imaging system or other automated analyses, such as colour spectrophotometry, X-ray fluorescence, and high-resolution magnetic susceptibility with the Geotek MSCL-XZ. All these measurements benefit from having the flattest surface possible.

Immediate line-scan imaging
Immediate imaging of cores after they are split preserves an invaluable archival record of each core section prior to any oxidation effects. Precise depth-registered images can be correlated with other data sets or used when describing core. The Geotek Geoscan IV linescan imaging camera, used on the Geotek MSCL-CIS, has 3 CCDs (2048 pixels each) and splits and filters the incoming light into three non-overlapping channels of red, green, and blue for true colour separation. Averaged image data can be converted to these RGB values and saved in a separate file to facilitate quantitative comparisons between cores and other down-core measurements. The camera is factory-calibrated and a standard photographic 18% grey card is used for field calibration, enabling images to be qualitatively or quantitatively compared to each other.

Automated split-core measurements
The Geotek MSCL-XZ benchtop measurement system can make measurements of spectral colour, magnetic susceptibility, and elemental composition via X-ray fluorescence (XRF) on split core surfaces. Reflectance spectra are collected in 39 spectral bands by a Minolta colour spectrophotometer to provide accurate colour data, including Munsell representations. True sediment or rock colour prior to core oxidation is a valuable correlation parameter for ore mineralogy, sedimentology, and climate research. Split-core inductive measurements of magnetic susceptibility are made with a Bartington MS2E “point” sensor that provides high down-core spatial resolutions. Core oxidation can damage magnetically susceptible minerals. Variations in magnetic susceptibility correlate with changes in sedimentary provenance and/or diagenetic environment. X-ray photons excite electrons in the sediment, releasing characteristic X-rays for each element which are collected by an Innov-X X-ray fluorescence (XRF) spectrometer. Elemental analyses can be used directly in environmental studies or indirectly as proxies for changes in mineralogy.

On-site grain size analysis
Grain size is not generally a parameter that benefits from field measurement; however, gas hydrate expeditions present an exception. Gas hydrate is often concentrated in coarse-grained sediment layers, if such layers are present. It is often advantageous to make this observation in real time, so that the extent of this correlation can be quantified throughout the section. Small samples for grain size analysis via rapid laser diffraction techniques permit correlations of hydrate concentration with grain size.

Self-contained laboratory container
All the equipment described above is installed in a self-contained, transportable 20-foot laboratory container. This laboratory is fully fitted with lights, air conditioning, sink, uninterruptible power supplies, ethernet network, and file server.

Sample processing speed
Eight one-metre sections of core can be split, imaged, and measured (including eight grain size measurements) in 2.5 hours using three trained scientists/technicians.

Split-Core Processing Lab Specifications

• Core accepted: Section length: up to 155 cm; Diameter: 5-15 cm
• Core splitting: Geotek Core Splitter.
• Core imaging: Geotek core imaging system (MSCL-CIS) with Geoscan IV 3 x 2048 pixel line-scan camera.
• Automated split-core analysis: Geotek MSCL-XZ with Minolta colour spectrophotometer, Bartington magnetic susceptibility point sensor (MS2E), and Innov-X Omega X-ray fluorescence analyzer.
• Grain size analysis: Laser diffraction particle size analysis using a Malvern Mastersizer 2000 with a HydroMU dispersion unit (supplied in sedimentology or geochemistry van depending on requirements)

Download Geotek Split-Core Logging Service flyer in PDF format below