Geochemical dataset for \"Petrogenetic constraints on the formation of magmatic Ni-Cu(-Co) sulfide deposits in Proterozoic arcs\"

This dataset contains whole-rock major and trace element analyses, EPMA mineral compositions, LA-ICP-MS trace element data, and stable isotope measurements (δ³⁴S and δ¹⁸O) generated for the Paleoproterozoic Kylmäkoski and Stormi Ni-Cu-(Co) sulfide deposits in the Vammala Ni Belt, southwest Finland. The data were obtained to characterize the geochemical composition of magmatic sulfides and their silicate host rocks in order to constrain melt evolution, assimilation processes, and sulfide saturation conditions in a fossil subduction zone setting. All measurements are directly tied to individually documented drill core samples and include full analytical metadata, standards, reference materials, and associated uncertainties. The purpose of this dataset is to provide a complete and reproducible geochemical foundation for evaluating the petrogenesis of Ni-Cu sulfide mineralization in Proterozoic arcs.