Demonstration of hydrothermal ammonium mobilization in the Paleoproterozoic with possible implications for biological productivity. The data include organic carbon and nitrogen abundances and isotopic ratios, as well as metal abundances. Samples span from sedimentary rocks to altered igneous rocks, where lithologies are provided in the CN data file. The N-enrichment in the usually N-poor igneous rocks indicates transfer of ammonium from organic-rich sediments and can be used to estimate the ammonium concentration of the hydrothermal fluid at the time of deposition. More details are provided in Stüeken, E.E., Kirsimäe, K., Lepland, A. and Prave, A.R., 2023, Astrobiology, 23(2), pp. 195-212.