Source, isotope, noble-gas and spatial data for natural CO₂ systems in the Western Carpathian–Pannonian region

This dataset supports the study “Integrated isotope geochemistry and geological modelling reveal how tectonic structure controls the sources and migration of natural CO₂ in a post-orogenic back-arc system.” It contains 50 analytical records from 47 georeferenced localities in the Western Carpathian–Pannonian region. Forty-four records were retained for source interpretation, whereas six were excluded because of atmospheric contamination. The deposited files contain CO₂ concentrations and δ¹³C_CO₂ values used for source classification; He, Ne, Ar, Kr and Xe concentrations and measured R/Ra values for six noble-gas samples; WGS 84 sample coordinates; geological-domain and quality-control assignments; baseline source classifications; carbon-classification sensitivity scenarios; helium end-member sensitivity calculations; and structural-pathway sensitivity outputs.