Publication Date:
2022-10-26
Description:
© The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Dunlea, A. G., Murray, R. W., Tada, R., Alvarez-Zarikian, C. A., Anderson, C. H., Gilli, A., Giosan, L., Gorgas, T., Hennekam, R., Irino, T., Murayama, M., Peterson, L. C., Reichart, G., Seki, A., Zheng, H., & Ziegler, M. Intercomparison of XRF core scanning results from seven labs and approaches to practical calibration. Geochemistry Geophysics Geosystems, 21(9), (2020): e2020GC009248, doi:10.1029/2020GC009248.
Description:
X‐ray fluorescence (XRF) scanning of marine sediment has the potential to yield near‐continuous and high‐resolution records of elemental abundances, which are often interpreted as proxies for paleoceanographic processes over different time scales. However, many other variables also affect scanning XRF measurements and convolute the quantitative calibrations of element abundances and comparisons of data from different labs. Extensive interlab comparisons of XRF scanning results and calibrations are essential to resolve ambiguities and to understand the best way to interpret the data produced. For this study, we sent a set of seven marine sediment sections (1.5 m each) to be scanned by seven XRF facilities around the world to compare the outcomes amidst a myriad of factors influencing the results. Results of raw element counts per second (cps) were different between labs, but element ratios were more comparable. Four of the labs also scanned a set of homogenized sediment pellets with compositions determined by inductively coupled plasma‐optical emission spectrometry (ICP‐OES) and ICP‐mass spectrometry (MS) to convert the raw XRF element cps to concentrations in two ways: a linear calibration and a log‐ratio calibration. Although both calibration curves are well fit, the results show that the log‐ratio calibrated data are significantly more comparable between labs than the linearly calibrated data. Smaller‐scale (higher‐resolution) features are often not reproducible between the different scans and should be interpreted with caution. Along with guidance on practical calibrations, our study recommends best practices to increase the quality of information that can be derived from scanning XRF to benefit the field of paleoceanography.
Description:
Funding for this research was provided by the U.S. National Science Foundation to R. W. M. (Grant 1130531). USSSP postcruise support was provided to Expedition 346 shipboard participants A. G. D., R. W. M., L. G., C. A. Z., and L. P. Portions of this material are based upon work supported while R. W. M. was serving at the National Science Foundation.
Keywords:
XRF scanning
;
Quantitative XRF
;
Paleoceanography
;
Sedimentary geochemistry
;
XRF calibration
;
XRF intercomparison
Repository Name:
Woods Hole Open Access Server
Type:
Article
