Nuclear microprobe in geological applications: Where do we go from here?

The past decade saw a rapid growth in geological applications of the nuclear microprobe, particularly as an in-situ trace-analyser using the PIXE technique. The success of micro-PIXE stems directly from the sensitivity for trace element detection at the parts-per-million concentration level. Microns spatial resolution enables studies of microscopic features such as zoning in minerals, the non-destructive feature is suited to studies of rare microscopic samples such as melt inclusions. The large penetration depth enables studies of fluid inclusions without decrepitation. In mantle petrology, significant results were obtained with direct application in diamond exploration. Despite generally poor detection limits for REE and in heavy minerals, important geochemical marker elements such as LILE and HFSE occur in discrete phases at levels accessible by micro-PIXE, allowing their exploitation in studies spanning from magma genesis and evolution, through to ore deposit genesis and metamorphism studies. In recent years competing methods such as the laser ablation microprobe and synchrotron radiation microprobes challenge the nuclear microprobe advantages. The review attempts to identify promising directions for the nuclear microprobe applications in geology and for technical development in order to maintain its advantage. (C) 1997 Elsevier Science B.V.