Encyclopedia of geology, five volume set, volume 1 5 (encyclopedia of geology series) ( PDFDrive ) 97

Technique Output Output Output Sample type Advantages Disadvantages X ray analysis Quantitative elemental composition of small volume (several cubic mm) Major elements detected using energy dispersive spectrometer (SEM or microprobe) Trace elements detected using wavelength dispersive spectrometer (microprobe) Polished rock samples, or grains set in resin and polished High spatial resolution; gives quantitative data with estimate of uncertainty; well established technology; wide range of elements Sample preparation can be slow; errors can be large for some elements; problems of analysis statistics for heterogeneous minerals X ray fluorescence spectroscopy Quantitative major and trace elemental composition of a crushed homogenized sample Crushed and homogenized sample then compressed or melted and quenched into small disks Gives major and trace elements simultaneously; produces data for Al and Si in rocks as well as a range of metals; well established technology Sample preparation can be slow; relies on sample type specific calibration curve; matrix effects can be large; instrumental set up can be arduous X ray diffraction Qualitative presence or absence of minerals in crushed sample Fairly quick; well established technology; large database of minerals for comparison Semi quantitative in most cases; difficult for minerals with solid solutions; difficult for poorly crystalline materials; difficult with very complex mixtures Relative proportion of minerals in a rock or sediment mixture for suitably prepared samples Mineral composition 58 ANALYTICAL METHODS/Geochemical Analysis (Including X-ray) Table X ray techniques commonly used in geochemical analysis