XRF Analyses of Sediment Cores from the Japan Margin Trench

The samples were collected from the R/V Natsushima 13-02 and 13-19 from the Japan Trench slope and Mid-Slope terrace for studying earthquake generated turbidites. The focus was on the 2011 Mw9.0 Tohoku earthquake and tsunami. Wet chemistry x-ray fluorescence elemental analyses were conducted with a Spectro XEPOS III® X-Ray Fluorescence Spectrometer with a Palladium X-Ray tube and silicon drift detector (SDD) in the laboratory of Dr. Bopp at Rensselaer Polytechnic Institute. The samples were packed in 3.2cm diameter polyethylene cylinders with one end covered by a 4μ prolene® (polypropylene) film. The samples were irradiated through the prolene with emissions from three secondary targets (Mo; Al2O3 (barkla scatter); and HOPG (Bragg interference)). Quantification was based on a proprietary program, TurboQuant Powders, supplied with the instrument calibrated to analyses of sediment and soil Standard Reference Materials (NIST SRMs 1944, 2702, 2704, and 2709). Additional assessment of the data quality was provided by XRF analyses of internal laboratory standards and other sediment samples that had been previously analyzed by ICP/MS or atomic absorption spectroscopy in the research groups of one of Richard Bopp at RPI and the Lamont-Doherty Geological Observatory (LDEO) of Columbia University. For the elements reported (Cu, Pb, Zn, Cr, Ni, As, Si, Al, Fe, Mn, Ti, Ca, Sr, and K) the relative standard deviation of multiple analyses of SRMs and samples was 5% or less. Applications of this XRF technique to sediment sample analysis have been described in several publications from the laboratory at RPI (Blount, 2009; Merrill, 2010; Graber et al., 2010).