Archaean hydrothermal systems in the barberton greenstone belt and their significance as a habitat for early life

Hydrothermal systems have played an important role in shaping the 3.54-3.23 Ga volcano-sedimentary succession of the Barberton greenstone belt. Evidence for relatively low-temperature (≤150°C) seafloor hydrothermal activity is widely recorded in extensive silicification of volcanic and sedimentary rocks, leaching of elements commonly mobile during water-rock interaction, and extensive hydraulic fracturing. Evidence for the presence of high-temperature hydrothermal vents is scarce and restricted to a massive sulphide deposit near the top of the succession. Many of the zones affected by seafloor alteration are spatially associated with traces of early life, such as carbonaceous matter and bioalteration features. Diffuse venting of low-temperature hydrothermal fluids was a widespread phenomenon on the Palaeoarchaean seafloor, making it an ideal habitat for hyperthermophiles and the possible birthplace of life during earlier times.