Umeå universitets logga

Portable and core-scanning X-ray fluorescence (XRF) instruments have become increasingly utilizedin making rapid, non-destructive chemical characterizations with high spatial resolution on a range of materials.Since basaltic cores are often highly fractured and uneven, portable XRF (pXRF) is preferred to conduct discretechemical analyses. However, in this case, the user must select the location for each analysis, which can lead tobiased datasets. Alternatively, XRF core-scanning (XRF-cs) instruments take a series of measurements alonga section of core, increasing the number of analyses and, therefore, eliminating some of the bias introducedby discrete analyses conducted with a pXRF. The XRF-cs does, however, still require a flat sampling surfacealong the core that does not include void spaces, making rigid, vesicular, and often cracked basalts suboptimaltargets.We collected 797 XRF-cs measurements on three basaltic cores collected during the International OceanDiscovery Program Expedition 396 to evaluate how effectively an XRF core scanner can build large, chemicallyrepresentative datasets.We developed a method for filtering XRF-cs measurements and calibrated the data usingdiscrete calibrated pXRF analyses and compared the XRF-cs data to pXRF and conventional bulk-rock data usingvarious immobile (e.g., Al, Ti, Zr, Ni, Mn, Zn) and mobile (e.g., K, Ca, Sr) elements. The comparison betweendatasets shows that (1) the XRF-cs data reproduce trends observed by pXRF and conventional bulk-rock data atboth the regional scale and the core scale, and (2) in some cases, the higher spatial resolution of the XRF-cs data reveals geochemical variations that are otherwise obscured using discrete analyses. The workflow outlined bythis study can be used to select samples for future studies by efficiently providing reliable geochemical data forcharacterizing new and legacy hard-rock cores.