μ-PIXE analysis of monazite for total U–Th–Pb age determination

Abstract

U–Th–Pb chemical age determinations of monazite have been successfully determined using μ-PIXE at the Legnaro scanning proton microprobe facility, as well as the concentration of rare earth and other trace elements. Experimental details and the analytical procedure are described, and the results obtained are compared with data obtained using EMPA and SHRIMP II on the same analysed monazite grains, indicating that the μ-PIXE technique is an extremely powerful tool for monazite geochronology, both for the small error in the age determination, and in terms of detection limit, giving the possibility to date much younger monazite crystals than with EMPA. In addition, the high spatial resolution and the non-destructive character of this technique, potentially allows for the analysis of small monazite crystals along inclusion trails within porphyroblasts and/or present in the surrounding matrix, and to relate their age to that of the deformation in metamorphic rocks.