The trace element analyses were conducted using wavelength-dispersive X-ray fluorescence spectrometry on pressed pellets using standard Norrish and Hutton (1969) procedures as described in Potts (1987) and as used by Cameron (2000). Well-calibrated international standards were used as a check of the analyses. The routine was customized for inter-elemental X-ray interferences in rocks of basaltic and felsic compositions. By comparing results on well-characterized rock standards, DGGS found in 2006 that the UAF routines yield more accurate trace-element results and in 2007 we chose to perform the Nb, Rb, Sr, Y, and Zr analyses using this procedure.
