The origin and evolution of microbial methane metabolism have been closely linked to the global carbon and sulfur biogeochemical cycles and the evolution of the Earth's surface system. Exploring geological records of methanogenesis and methane oxidation is the basis and prerequisite for revealing these relationships. The occurrence of highly 13C-depleted organic carbon in the Neoarchean rocks has been interpreted as results of methanogenesis and anaerobic methanotrophy. Some distinctive sedimentary structures, e.g., the molar-tooth structure in the Proterozoic carbonate rocks, has been proposed to be related with methane release in carbonate sediments, though direct evidence is lacking. The geological records of methane metabolism in Precambrian, however, are generally scarce. Authigenic carbonates have been discovered from the Ediacaran (~635-539 Ma) succession in South China. They are mainly composed of calcite and occur as either nodules and lenses that are generally aligned with sedimentary laminations, or cements in dolomicrite. Field investigations have confirmed their occurrence in multiple horizons of the Ediacaran Doushantuo and Dengying formations. The 87Sr/86Sr values of calcite nodules ranging from 0.7080 to 0.7085, resembling that of contemporaneous seawater, suggest that seawater is the main source of sediment pore water. Calcite nodules and cements generally have pronounced negative δ13C values (as low as ‒38‰) compared to surrounding dolomite, indicating that carbon source of calcite nodules and cements may be partially derived from methane oxidation. It has been proposed that the formation of calcite nodules and cements is related with anaerobic methane oxidation (AOM) driven by microbial sulfate reduction (MSR), which occurs in the sulfate methane transition zone (SMTZ) below sediment-water interface. The presence of SMTZ in the superficial layer of sediments below sediment/water interface requires a higher concentration of seawater sulfate (~10 mM) in Ediacaran, indicating that the concentration of seawater sulfate increased significantly after the Neoproterozoic global glaciation, which is consistent with the increase of atmospheric oxygen content and corresponding increase of oceanic sulfate input flux during the Neoproterozoic Oxygenation Event (GOE).