Split Core Logging with XRF

There are some measurements such as X-ray fluorescence, visual description that require the core surfaces to open, and cut flat. 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 therefore offer a turnkey solution to split core logging, which includes core splitting, imaging and core logging. We also to rent our specialist logging facility to our clients should they wish to conduct their visual logging in conjunction with the above mentioned process.

However, if these measurements are required in a timely fashion, core must be split on site. Geotek therefore 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 the splitting of core liners that in turn enable the best possible split core surfaces with reproducible sediment thicknesses. The core from the Geotek core splitter is ideal for high-resolution imaging with the Geotek MSCL-CIS linescan imaging system.

Linescan Imaging/Core Scanning

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) that split and filter 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.

Split Core Multi-Sensor Core Logging

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. The following split core measurements are conducted.

• The Minolta colour spectrophotometer acquires reflectance spectra from 39 spectral bands by a 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 Olympus Vanta X-ray fluorescence (XRF) spectrometer, or Geotek helium-flushed XRF spectrometer. Elemental analyses can be used directly in environmental studies or indirectly as proxies for changes in mineralogy.