A note on the fluxes of abiogenic methane and hydrogen from mid-ocean ridges

Keir, Robin (2010) A note on the fluxes of abiogenic methane and hydrogen from mid-ocean ridges Geophysical Research Letters, 37 (24). L24609. DOI 10.1029/2010GL045362.

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Abstract

The concentrations of methane and hydrogen in hydrothermal vent fluids issuing from mid-ocean ridges tend to fall into two groups, one with high concentrations of these gases in ultramafic-hosted vent fields and a second group with relatively lower concentrations in basalt-hosted vent fluids. Ultramafic-hosted systems, however, appear to be restricted to slow-spreading ridges and constitute only a fraction of the hydrothermal systems found there. In this note, the hydrothermal fluxes of methane and hydrogen have been calculated by estimating the percentages of the total subsurface hydrothermal circulation that circulate through each type of host rock. Even though the percentage of the total subsurface flow that is affected by serpentinization appears to be rather small (8%), it still appears that this process produces about 70% of the total mid-ocean flux of these gases. The total production of methane and hydrogen is calculated to be about 20 x 10(9) mol yr(-1) and 190 x 10(9) mol yr(-1), respectively. The hydrogen flux is comparable to that most recently calculated on the basis of the rate of hydration of mantle rock in newly formed crust and the stoichiometry of the serpentinization reaction. This suggests that, except for the production of methane, a major portion of the hydrogen produced in the subsurface is not consumed before venting.

Document Type: Article
Keywords: Meeresgeologie; MID-ATLANTIC RIDGE; EAST PACIFIC RISE; HYDROTHERMAL VENT FIELDS; CENTRAL INDIAN RIDGE; ODP HOLE 504B; DEGREES N; ULTRAMAFIC ROCKS; TRIPLE JUNCTION; HELIUM-ISOTOPES; OCEANIC-CRUST
Research affiliation: OceanRep > GEOMAR > FB2 Marine Biogeochemistry > FB2-MG Marine Geosystems
Refereed: Yes
DOI etc.: 10.1029/2010GL045362
ISSN: 0094-8276
Date Deposited: 10 Jan 2012 14:11
Last Modified: 20 Jun 2017 12:52
URI: http://eprints.uni-kiel.de/id/eprint/13360

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