A global dataset of helium isotopic data in tectonically and hydrothermally active geological environments

Since the early 1970s, helium isotopes ³He and ⁴He have been used to trace the sources of deep-seated fluids in various geodynamic settings. Observed variations in the ³He/⁴He ratio measured at the surface are ascribed to source compositional variability or differences in the efficiency of mantle He transport through the continental crust. Given the high scientific relevance of helium isotopes across a wide range of geoscientific applications, it appears essential to compile existing bibliographic information on their global spatial distribution. Here, we present a dataset of the helium isotopic composition in geofluids from hydrothermal and tectonically active areas. Using two global databases published in 2006 and 2015 as a starting point, we have reviewed the existing international literature to compile a comprehensive database of data published up to 2024. The goal is to provide a resource for investigating potential relationships between helium isotopes with other geological, hydrogeological, and geophysical parameters and to formulate hypotheses regarding the role of geofluids in crustal deformation processes.