The problem of deep carbon-An Archean paradox

Carbonaceous compounds contained within the black chert dikes could have been generated abiotically by a process similar to Fischer-Tropsch synthesis at elevated temperatures (200-300 °C) and pressures (500 bar) at a paleo-depth of 2 km within the hydrothermal system. The “primordial medium” in which life first evolved may thus have been a silica-rich slurry with a low pH and a high CO2 content which contained basic abiotic organic building blocks fundamental to the origins of life. The abiotic organic output from these hydrothermal systems may overwhelm any early biospheric geochemical signal and may therefore be the most difficult environment in which to recognise the early biospheric record.