MAJOR-ELEMENT RATIOS IN SYNTHETIC FLUID INCLUSIONS BY SYNCHROTRON X-RAY-FLUORESCENCE MICROPROBE

Individual fluid inclusions in quartz were investigated by synchrotron radiation X-ray fluorescence (SXRF) microprobe to develop protocols f or major-element microanalysis. Studies were conducted of synthetic fl uid inclusions in Brazilian quartz that contain fluids of known NaCl-C aCl2-H2O and KCl-H2O compositions. Inclusions were irradiated by synch rotron X-rays and the resulting energy-dispersive spectra were correct ed for fluorescence yield and absorption effects to obtain Ca/Cl and K /Cl ratios. Results are commonly better than +/- 30% relative to the n ominal ratio. Element ratios obtained by SXRF may be combined with res ults of heating and freezing studies to characterize non-destructively the bulk major-element composition of individual inclusions. Extensio n of the analytical protocol to elements of higher atomic number (e.g. , trace and transition elements) will result in better precision as ab sorption effects and peak overlaps become less problematic.