Wolframite and cassiterite are the most important ore minerals in tungsten and tin deposits. In-situ trace element mapping via laser ablation inductively coupled plasma-mass spectrometry (LA-ICP-MS) can effectively constrain the origin and evolution of ore-forming fluids, as well as the mechanisms of element migration and precipitation. Previous studies have mainly focused on trace element mapping of individual deposits, lacking systematic comparisons of uranium occurrence states and trace element distributions in wolframite and cassiterite from deposits of diverse genetic types. Moreover, the specific guidance of elemental mapping for U-Pb geochronology remains poorly constrained. To address these issues, six samples of wolframite and cassiterite collected globally from quartz vein-type, greisen-type, skarn-type and pegmatite-type tungsten-tin deposits were investigated using LA-ICP-MS elemental mapping technique. The distribution patterns of trace elements and the occurrence mechanisms of uranium in these samples were revealed. The results show that wolframite and cassiterite from various deposit types exhibit distinct trace element zoning features. Wolframite is generally enriched in heavy rare earth elements (HREEs) and high field strength elements (HFSEs), and uranium shows strong positive correlations with these elements. The trace element distribution of cassiterite is dominated by isomorphous lattice substitution, and uranium is preferentially concentrated in HFSE-rich domains. The distinct elemental zoning characteristics indicate three distinct crystallization models, namely continuous crystallization in closed systems, crystallization under stable fluid conditions, and multistage fluid superimposition and modification. Compared with previous single deposit investigations, this comparative study on wolframite and cassiterite from multiple genetic type deposits confirms that fractures, altered rims and abrupt compositional zones should be avoided during U-Pb dating, whereas domains with stable uranium contents and continuous rhythmic zoning are optimal for geochronological analysis. This study further highlights the application potential of elemental mapping in U-Pb dating, and provides reliable references for constraining metallogenic ages and tracing material sources of tungsten-tin deposits.
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