Microbiology and Biogeochemistry of Deep Hydrogeologic Environments of the Witwatersrand Basin, South Africa

Samples were collected from water-emanating boreholes in South African Witwatersrand Basin Au<br>mines near Carletonville, across a variety of geological formations, hydrological regimes, temperatures<br>and depths (up to 3.3 km below land surface). The boreholes intersected the Transvaal dolomite, the<br>Ventersdorf volcanic units and the Central Rand quartzite. Samples of the mining water and water<br>dripping from fractures in access tunnels were also collected. The microbial communities found in the<br>subsurface fissure water reflect the source of the water, the principal terminal electron acceptor and the<br>hydrogeological history.