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doi:10.2204/iodp.proc.320321.203.2012

Conclusions

We present scanning XRF data along the splice of Site U1338 (21,000 total sample measurements, with 17,000 along the splice) and show their use to explore the history of the equatorial Pacific productivity zone. We found that we could scan the Site U1338 splice in a reasonably short amount of time, averaging a little over 1 h apiece to scan ~250 sections along the Site U1338 splice for Al, Si, K, Ca, Ti, Mn, Fe, and Ba. Raw data are a volume measurement, however, and must be scaled, normalized, and eventually calibrated to make an estimate of sediment composition. The NMS data reduction process we describe helps to make correlations between raw peak areas and measured chemical compositions more linear so that calibration is easier. To achieve good results, care must be taken to choose a sediment compositional model (median composition and type of sediment components) that is similar to the sediments under analysis. Calibration is the final step to convert XRF scan data to a compositional estimate. Ideally, sufficient numbers of samples are measured by other analytical methods that some of the data are left out of the calibration and can be used as check data.