TIME-OF-FLIGHT SIMS (TOF-SIMS) ANALYSES OF MELT INCLUSIONS

Time of Flight Secondary Ion Mass Spectrometry (ToF-SIMS) is a valuable tool for analyzing very small geological materials, like exposed melt inclusions, because it provides high mass and spatial resolution with little sample destruction. In this study, ToF-SIMS quantitative analysis of major and trace elements and isotope ratios were determined in a vapor bubble wall of a melt inclusion and in its host clinopyroxene. Two standard glass reference materials, BCR-1 and JB-2, of similar composition were used. Results indicate that quantification using ToF-SIMS is possible for many mineral-forming elements. High mass and spatial resolution elemental maps clearly show the preferential partitioning of S, Na, Cu, Au, Li, and K into the vapor bubble in the clinopyroxene-hosted melt inclusion. Moreover, the presence of C, H, and associated hydrocarbon fragments in the element maps suggest the heterogeneous entrapment of brine and hydrocarbon metal-bearing phases in the melt inclusion. Variability in isotope ratios found particularly in the standard reference materials suggests either or both heterogeneous distribution in the sample or analytical variability. In any case, more research is necessary in order to better constrain the multitude of variables.