In situ apatite fission track, UPb and trace elements analysis using LA-ICP-MS

The integrated application of apatite U-Pb geochronology, fission track (FT) thermochronology, and trace-element geochemistry offers invaluable insights into the evolution of crystallization, mineralization, exhumation and provenance determination. However, a standardized protocol for such multi-method analysis on a single grain has not yet been well established. Here, we present a LA-ICP-MS-based apatite FT, U-Pb and trace element analyses procedure, detailing optimized sample preparation, measurement and data reduction strategies. This protocol was tested on six international apatite reference materials (Durango, Fish Canyon Tuff, Madagascar, McClure Mountain, Mount Dromedary, and Eppawala-Ap). By improving sample preparation and implementing a selective signal extraction technique, we achieve high-precision results: FT ages with precisions better than 4.7% and U-Pb ages better than 8% for most samples. We recommend Mount Dromedary apatite as a primary reference material for this multi-method dating due to its suitable U content (~17 ppm) and concordant ~100 Ma U-Pb and FT ages. This protocol overcomes the spatial-matching challenges, enhances analytical efficiency, and facilitates the extraction of novel information for tectonics evolution and mineral exploration studies.