USGS Home
Contact USGS
Search USGS

X-Ray Fluorescence Major, Minor, and Trace Element Chemistry

Task Objectives

This task provides for high precision determinations of the 10 major rock-forming elements in solid geologic samples using wavelength dispersive x-ray fluorescence (WDXRF) and for the determination of 30 minor and trace elements in solid geologic materials using energy dispersive x-ray fluorescence (EDXRF). The accuracy achievable using the WDXRF technique for major element determination is unsurpassed by any other instrumental technique. The error of determination is typically 0.5% relative error or less for major elements at crustal abundance levels. This technique has a long history of providing precise and accurate results to various programs in the Geologic Discipline. The EDXRF technique determines concentration levels of V, Cr, Ni, Cu, Zn, Ga, Ge, As, Se, Br, Rb, Sr, Y, Ar, Nb, Mo, Ag, Cd, Sn, Sb, Cs, Ba, La, W, Pb, Bi, Ce, Nd, Th, and U. The percent relative standard deviation is typically beween 5% and 10% for elements free from overlaps and a concentration of >100 ppm. The technique is non-destructive, relatively fast (approximately 40 samples/day) and requires little sample preparation.

Statement of Work

Provide wavelength dispersive XRF (WDXRF) analysis for major amd minor elements and EDXRF analysis for minor and trace elements in solid geologic materials. The WDXRF technique uses a lithium tetraborate fusion disk sample for presentation to a 13-channel simultaneous wavelength dispersive X-ray fluorescence spectrometer. The method is well-proven for analyzing all types of rocks, soils, and most types of minerals. The results are important in identification and chemical classification of geologic materials, as well as following temporal amd mass balance chages in geologic environments.

The EDXRF technique uses a homogeneous powdered sample which is placed in a 20 mm cuvette with an attached prolene film to prevent sample spilling. The cuvette is introduced into a Spectro X-Lab 2000 spectrometer for analysis. Rocks, stream-sediments, and soils are typically analyzed to provide mineral and trace element data for petrologic, economic, and environmental studies.

References to non-USGS products and services are provided for information only and do not constitute endorsement or warranty, express or implied, by the USGS, USDOI, or U.S. Government, as to their suitability, content, usefulness, functions, completeness, or accuracy.

Return to top of this page | Previous Task | Next Task | Task List