Developments of fluid inclusion analysis by using high-energy ion beam

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In this study, quantitative trace element analytical techniques for single fluid inclusions using proton-induced X-ray emission(PIXE) have been developed to investigate an elemental transportation by Earth's fluid. The main subjects were as follows : 1)developments of the quantification and the calculation method of total X-ray emission from a fluid inclusion buried in mineral matrix : 2)evaluation of the developed quantification and the calculation by using PIXE measurements of house-made fluid-inclusion analogue samples with known contents and shape : 3)estimation of the analytical error for trace-element determinations of natural fluid inclusion : 4)trace-element determinations of single fluid inclusions in a hydrothermal quartz vein. The quantification and the calculation were developed on the basis of Campbell (1993)'s method for PIXE determination of trace elements in solids and Ryan et al. (1993)'s method for single fluid inclusion analysis using PIXE. By using the developed met … More hods, elements with concentrations of 10 to 1000 ppm in single fluid inclusion were measured with average estimated relative error of ±7%. For natural fluid inclusions with 30 μm radius and 20 μm depth in quartz, the total analytical errors were estimated to be ±40% relative for Ca,±16% for Fe,±13% for Zn,±12% for Sr,and ±11% for Br and Rb,by considering uncertainties in microscopic measurements of inclusion depths. Detection limits of 4 to 46 ppm for elements of mass numbers 25-50 were achieved for analyses of a spherical fluid inclusion with 30-μm radius and 20-μm depth in quartz at an integrated charge of 1.0 μC. The trace element compositions of single fluid inclusions in hydrothermal quartz veins from Kawakami village, Nagano Prefecture, Central Japan, were also determined by using the developed method. The elemental concentrations in the inclusions varied widely : 0.2-9 wt% for Ca and Fe,300-8000 ppm for Mn and Zn,40-3000 ppm for Cu,100-4000 ppm for Br,Rb,Sr,and Pb,and lessthan 100 ppm for Ge. Less