A common metabolism for sulfur bacteria is oxidation to sulphates such as gypsum and barite. These minerals are common is anaerobic acid-sulphate soils found on Earth currently and are considered a potential reason for the accumulation of sulphate in Archaean paleosols. This reflects circumstantial evidence for life in paleosols on Earth during the Archean, 3.42 to 3.46 Ga [1].