40Ar/39Ar incremental-heating data for welded spatter from the Camp dels Ninots maar (NE Spain)

This dataset contains ⁴⁰Ar/³⁹Ar incremental‐heating data for a welded basaltic spatter unit from the Camp dels Ninots (CN) maar–diatreme in northeastern Spain. The dated sample was recovered from core CP2 at 132.40 m depth within the diatreme infill and consists of syn‐eruptive welded spatter. Groundmass separates were prepared using standard mineral separation and rigorous acid‐leaching procedures, and irradiated at the OSU TRIGA reactor to produce ³⁹Ar from ³⁹K. Incremental‐heating experiments were performed at the Argon Geochronology Laboratory of Oregon State University using a ThermoFisher Scientific ARGUS-VI mass spectrometer, and ages were calculated relative to the Fish Canyon Tuff sanidine standard (FCT-2-NM) with ArArCALC v2.6.2. The archive includes raw argon isotope measurements, irradiation parameters and J values, step-by-step age spectra, and derived plateau and inverse-isochron ages for the welded spatter groundmass.