⁸⁶Kr excess and other noble gases identify a billion-year-old radiogenically-enriched groundwater system.

ABSTRACT: Deep within the Precambrian basement rocks of the Earth, groundwaters can sustain subsurface microbial communities, and are targets of investigation both for geologic storage of carbon and/or nuclear waste, and for new reservoirs of rapidly depleting resources of helium. Noble gas-derived residence times have revealed deep hydrological settings where groundwaters are preserved on millions to billion-year timescales. Here we report groundwaters enriched in the highest concentrations of radiogenic products yet discovered in fluids, with an associated ⁸⁶Kr excess in the free fluid, and residence times >1 billion years. This brine, from a South African gold mine 3 km below surface, demonstrates that ancient groundwaters preserved in the deep continental crust on billion-year geologi

SUBMITTER: Warr O 

PROVIDER: S-EPMC9246980 | biostudies-literature | 2022 Jun

REPOSITORIES: biostudies-literature