Dataset for: Characterization of coesite-bearing impact melt glass from the Hapcheon crater, Korea: Trimodal phase architecture, shock metamorphism, and implications for 40Ar/39Ar geochronology

Primary data sets for the paper: Lee, J.-Y., Kim, J., and Hong, S.-S. (2026). Characterization of coesite-bearing impact melt glass from the Hapcheon crater, Korea: Trimodal phase architecture, shock metamorphism, and implications for 40Ar/39Ar geochronology. Meteoritics & Planetary Science (article 70216). https://doi.org/10.1111/maps.70216 The Hapcheon impact crater (~1.4 km apparent diameter) is the first confirmed impact structure on the Korean Peninsula. All samples are impact melt glass separates from borehole 20HCL04 (depths 51.40, 63.85, and 65.75 m); thin-section work used the 63.85 m material. The archive contains: (1) EPMA-WDS data (5 um spot): instrument-native raw quantification files and summary for the 37 points of Table 1, a machine-readable Table 1 with trimodal classification (CORE n=23 / MANTLE n=6 / UNCERTAIN n=8) including per-point Cr2O3, a complementary 71-spot element table (polished sections N24/N25/N15/N20), WDS element maps (K, Si, Fe, O), and BSE/SE images of the analyzed grains. (2) Confocal Raman spectroscopy (532 nm, <1 um spot): the 34-spectrum survey data set (coesite confirmed in 74% of spectra; Table 2, Figs. 7-8, S2) and the separate 30-point EPMA-Raman colocation data set on grain 4 (Fig. 4), each as instrument text spectra with processing results (521 cm-1 S/N, detection grades), point photomicrographs, field-of-view overview images, and a point-by-point coordinate mapping table. (3) Bulk powder XRD: three subsamples of the 63.85 m glass concentrate (PANalytical X'Pert3, Cu Ka, 40 kV / 30 mA; Fig. 9). (4) 40Ar/39Ar step-heating geochronology (KBSI): the laboratory export workbook with full step-by-step isotope-ratio data for all runs, plus flat machine-readable versions of Table S1 (nine runs, 81 steps, with per-run J values) and Table S2 (inverse-isochron results with full external 2-sigma uncertainties). Flux monitor: Fish Canyon sanidine, 28.201 Ma (Kuiper et al., 2008); decay constants of Steiger and Jaeger (1977); atmospheric 40Ar/36Ar = 298.56 (Lee et al., 2006). (5) Python 3 data-analysis code (Raman ALS baseline correction and S/N grading, inverse-isochron recalculation, Figure S4 image segmentation). The archive also includes machine-readable Table 3 (plateau + inverse-isochron summary) and the quantitative image analysis behind Figure S4 (feature segmentation of the x900 BSE image, size distribution, and orientation-rose analysis). README.md provides a full directory guide, column dictionaries, and provenance notes; FILE_MANIFEST.csv lists MD5 checksums for every file (1,049 files). Photomicrograph JPEGs were re-encoded at quality 85 to reduce archive size; all spectra, tables, and instrument files are bit-identical to the originals.