10.1594/PANGAEA.994131Ota, HayuHayuOta0009-0001-7029-2067Atmosphere and Ocean Research Institute, The University of TokyoKuroda, JunichiroJunichiroKuroda0000-0002-2218-4854Atmosphere and Ocean Research Institute, The University of TokyoOrihashi, YujiYujiOrihashi0000-0001-7715-3847Faculty of Science and Technology, Graduate School of Science and Technology, Hirosaki UniversitySchmitz, Mark DMark DSchmitz0000-0003-2888-0321Department of Geosciences, Boise State UniversityTakashima, ReishiReishiTakashima0000-0003-1830-6887The Center for Academic Resources and Archives, Tohoku University MuseumPANGAEA2026Cretaceous-Paleogene boundaryEast AsiaIODP³Osmiumzircon U-Pb geochronologySample code/labelSECTION, heightMain LithologySodium oxideMagnesium oxideAluminium oxideSilicon dioxidePhosphorus pentoxidePotassium oxideCalcium oxideTitanium dioxideChromium(III) oxideManganese oxideIron oxide, Fe2O3Nickel oxideLoss on ignitionX-ray fluorescence spectrometer (XRF), Rigaku Holdings Corporation, ZSX Primus IIDataset10.1038/s43247-026-03602-z105 data pointstext/tab-separated-valuesCreative Commons Attribution 4.0 InternationalThis dataset contains major element compositions of the KWR4 sample series collected from the high-resolution interval of the Kawaruppu section, Nemuro Group, Hokkaido, Japan. These data were obtained to evaluate whether the osmium isotope ratios and platinum group element concentrations of the same samples were affected by diagenetic alteration. Major element compositions were measured by a RIGAKU ZSX Primus II X-ray fluorescence (XRF) spectrometer at Atmosphere and Ocean Research Institute (AORI), the University of Tokyo (Kashiwa).Japan Society for the Promotion of Sciencehttps://doi.org/10.13039/50110000169117K05674High resolution age model and paleoenvironmental change for K/Pg boundaryJapan Society for the Promotion of Sciencehttps://doi.org/10.13039/50110000169118KK0091Improvement of Cretaceous Geologic Time ScaleJapan Society for the Promotion of Sciencehttps://doi.org/10.13039/50110000169121H04503Environmental changes during the Latest Cretaceous Mass Extinction Event recorded in the complete K/Pg boundary sequence discovered firstly in East AsiaJapan Society for the Promotion of Sciencehttps://doi.org/10.13039/50110000169122H01342The Cretaceous-Paleogene Boundary in the Southern Hemisphere: Osmium isotopic record to fingerprint flood basalt volcanismJapan Society for the Promotion of Sciencehttps://doi.org/10.13039/50110000169122K18426Linkage of the Earth's tipping points and the subseafloor biosphereJapan Society for the Promotion of Sciencehttps://doi.org/10.13039/50110000169123H00153Analysis of internal Earth nitrogen using pupulin nitrogen isotope ratioJapan Society for the Promotion of Sciencehttps://doi.org/10.13039/501100001691JPJSCCA20250004Warm-period Climate Change Research Center with the International Ocean Drilling School [WarmCCR]