HYDROGEN AND METHANE FORMATION WITH SERPENTIZATION OF MANTLE HYPERBASITE OF THE OCEAN AND OIL GENERATION

Abstract

The intensity of hydrogen and methane generation in the course of serpentinization was calculated by the method of the thermodynamic modeling of the interaction of sea water with mantle peridotite in the temperature range of 25-400°C, the pressure range of 1-5 kbar, and varying water-rock relationships. Using the field and computed data available, we analyzed the variation of the mineral associations as a function of the value of the water-rock ratio during the serpentinization of peridotite under different geologic conditions. As follows from our calculations, the serpentization of oceanic mantle peridotites was accompanied by the emanation of huge amounts of hydrogen and methane under the conditions corresponding to the initial period of petroleum generation. The potential intensity of hydrogen and methane generation during the peridotite serpentinization was estimated qualitatively for the environments of rift zones, cooling oceanic lithosphere, and forearc basins. The resulting estimates proved the necessity of accounting for the role of the global serpentization process in the formation of the Earth fluid conditions, and for developing the fundamental and applied problems of oil and gas geology, irrespective of the biogenic or abiogenic hypotheses of oil and gas origin.