A Novel, <scp>Laser‐Based</scp> Microsampling Technique for <scp>Texturally Controlled</scp> , Combined and Complementary Sr and Nd Isotope Measurements in Silicate Minerals

The limitations of many in situ microsampling techniques, especially when applied to isotopic analyses, may result lower measurement precision and limit the ability compare different isotope systems within same phase or system between phases. High-precision, combined complementary measurements are typically limited whole-rock samples mineral separates at expense textural context. We demonstrate that laser ablation instruments could offer an effective, non-mechanical alternative micro-milling for delineating extracting single crystals, interstitial phases, sub-crystal scale features from soluble-resin thick sections column chromatography high ID-TIMS measurement. Systematic testing demonstrated both modern legacy capable ablating through plagioclase, pyroxene fused glass depths 200 μm. Modern software benefits identifying optically-indistinct petrographic features, chemical zoning avoiding alteration phases by using overlain high-resolution datasets. Extracting delineated targets varying geometry was achieved under binocular microscope common mineral-separation tools. Analysis RM used as proxies indicate (a) no significant thermal aureole on ablated margins affect measured parent-daughter ratios, (b) elevated risk contamination compared with traditional separation (c) excellent blanks low-yield analyses (d) high-precision results (87Sr/86Sr 143Nd/144Nd) sub-100 ng Sr loads sub-10 Nd loads.