Origin of hydrogen-nitrogen gas seeps, Oman

Sano, Yuji; Urabe, Akiko; Wakita, Hiroshi; Wushiki, Hisao

doi:10.1016/0883-2927(93)90053-j

Cited by 58 publications

(50 citation statements)

References 28 publications

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“…The field settings fall into four main groups: (1) surface manifestations in serpentinized ultramafic rocks; (2) boreholes in deep Precambrian shield crystalline rocks; (3) fluid inclusions in crystalline intrusions; and (4) volcanic and high temperature hydrothermal systems. Abiotic CH 4 , assumed to be related to FTT reactions has been reported at several sites with serpentinized ultramafic rocks, both on continents (ophiolites in Oman [ Fritz et al ., ; Sano et al ., ], New Zealand [ Lyon and Giggenbach , ], and Turkey [ Hosgormez et al ., ; Etiope et al ., ]) and at mid‐ocean ridges [e.g., Charlou et al ., ] and off‐axis spreading centers [ Kelley et al ., ; Proskurowski et al ., ]. In the last few years, isotopic data were reported for CH 4 dissolved in hyperalkaline springs in Greece (Othrys) [ Etiope et al ., ], Italy (Genova) [ Boschetti et al ., ], Japan (Happo) [ Suda , ], Canada [ Szponar et al ., ] and California [ Morrill et al ., ].…”

Section: The Stable Carbon and Hydrogen Isotopic Compositionmentioning

confidence: 99%

“…For instance, the one sample from Sano et al . [] for CH 4 from the Oman (Semail) ophiolite springs, while containing some mantle helium (3.9%) has a more 13 C‐depleted value (–34.5‰) than any of the other samples discussed above. Notably, this value is inconsistent with previous work published for nearby springs by Fritz et al .…”

Section: The Stable Carbon and Hydrogen Isotopic Compositionmentioning

confidence: 99%

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Abiotic Methane on Earth

Etiope

Lollar

2013

Reviews of Geophysics

484

437

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[1] Over the last 30 years, geochemical research has demonstrated that abiotic methane (CH 4 ), formed by chemical reactions which do not directly involve organic matter, occurs on Earth in several specific geologic environments. It can be produced by either high-temperature magmatic processes in volcanic and geothermal areas, or via low-temperature (<100 C) gas-water-rock reactions in continental settings, even at shallow depths. The isotopic composition of C and H is a first step in distinguishing abiotic from biotic (including either microbial or thermogenic) CH 4 . Herein we demonstrate that integrated geochemical diagnostic techniques, based on molecular composition of associated gases, noble gas isotopes, mixing models, and a detailed knowledge of the geologic and hydrogeologic context are necessary to confirm the occurrence of abiotic CH 4 in natural gases, which are frequently mixtures of multiple sources. Although it has been traditionally assumed that abiotic CH 4 is mainly related to mantle-derived or magmatic processes, a new generation of data is showing that low-temperature synthesis related to gas-water-rock reactions is more common than previously thought. This paper reviews the major sources of abiotic CH 4 and the primary approaches for differentiating abiotic from biotic CH 4, including novel potential tools such as clumped isotope geochemistry. A diagnostic approach for differentiation is proposed.

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Section: The Stable Carbon and Hydrogen Isotopic Compositionmentioning

confidence: 99%

Section: The Stable Carbon and Hydrogen Isotopic Compositionmentioning

confidence: 99%

Abiotic Methane on Earth

Etiope

Lollar

2013

Reviews of Geophysics

484

437

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“…At anoxic conditions, aqueous oxidation of ferrous minerals occurs via dissociation of water molecules and release of H 2 , as exemplified by net reactions Low‐temperature formation of H 2 by reactions like and is observed during aqueous alteration of ultramafic rocks (serpentinization) [ Abrajano et al , 1990; Sano et al , 1993; Charlou et al , 2002]. Although reactions – are energetically favorable in open systems where H 2 is removed, no organisms are known to gain energy from these pathways.…”

Section: Chemical Disequilibria As Sources For Metabolic Energy For Nmentioning

confidence: 99%

A model for low‐temperature biogeochemistry of sulfur, carbon, and iron on Europa

Zolotov

2004

J. Geophys. Res.

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[1] Galileo spacecraft data obtained from Jupiter's ice-covered satellite Europa suggest the existence of a subsurface water ocean. The formation of this ocean is a direct consequence of early igneous and hydrothermal processes that may have facilitated oxidation through H 2 and CH 4 escape. These processes could have led to a moderately alkaline sulfate-carbonate ocean and a moderately oxidized magnetite-bearing silicate mantle. When the ocean formed, low-temperature chemical disequilibria involving oceanic sulfate, bicarbonate, and ferrous minerals in underlying rocks could have provided multiple energy sources for chemotrophic organisms. Potential metabolic processes include oxidation of ferrous iron, sulfides, native sulfur, methane, hydrogen, and organic compounds, as well as reduction of water, sulfate, bicarbonate and carbonate ions (methanogenesis and acetogenesis), native sulfur, and ferric iron. If they occurred, these reactions would have provided close coupling for biogeochemical cycles of S, C, and Fe in the ocean. Periodic supplies of fresh rocks and/or aqueous fluids at the oceanic floor could drive these cycles throughout the satellite's history, including the present epoch. Signs of chemical disequilibria in the ocean would indicate chemical sources of energy for metabolism but should not be considered as indicators of life. In turn, observational signs of low-temperature redox equilibration among sulfur and carbon species would be suggestive of ancient life. INDEX TERMS:6218 Planetology: Solar System Objects: Jovian satellites; 1060 Geochemistry: Planetary geochemistry (5405, 5410, 5704, 5709, 6005, 6008); 1030 Geochemistry: Geochemical cycles (0330); KEYWORDS: Europa, ocean, mantle, life Citation: Zolotov, M. Y., and E. L. Shock (2004), A model for low-temperature biogeochemistry of sulfur, carbon, and iron on Europa,

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“…Higher concentrations of abiogenic CH 4 (units to tens of %) are documented in H 2 ‐ or N 2 ‐rich onshore seeps and geothermal springs (Abrajano et al. 1988; Sano et al. 1993), and in mid‐ocean ridge systems (Welhan & Craig 1979; Charlou et al.…”

Section: Introductionmentioning

confidence: 99%

New evidence for a mixed inorganic and organic origin of the Olympic Chimaera fire (Turkey): a large onshore seepage of abiogenic gas

2008

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The Chimaera gas seep, near Antalya (SW Turkey), has been continuously active for thousands of years and it is known to be the source of the first Olympic fire in the Hellenistic period. New and thorough molecular and isotopic analyses including methane (approximately 87% v ⁄ v; d 13 C 1 from )7.9& to )12.3&; d 13 D 1 from )119& to )124&), light alkanes (C 2 + C 3 + C 4 + C 5 ¼ 0.5%; C 6+ : 0.07%; d 13 C 2 from )24.2& to )26.5&; d 13 C 3 from )25.5& to )27&), hydrogen (7.5-11%), carbon dioxide (0.01-0.07%; d 13 C CO2 : )15&), helium (approximately 80 ppmv; R ⁄ Ra: 0.41) and nitrogen (2-4.9%; d 15 N from )2& to )2.8&) converge to indicate that the seep releases a mixture of organic thermogenic gas, related to mature type III kerogen occurring in Palaeozoic and Mesozoic organic-rich sedimentary rocks, and abiogenic gas produced by low-temperature serpentinization in the Tekirova ophiolitic unit. Methane is not related to mantle or magma degassing. The abiogenic fraction accounts for about half of the total gas released, which is estimated to be well beyond 50 ton year )1 . Ophiolites and limestones are in contact along a tectonic dislocation leading to gas mixing and migration to the Earth's surface. Chimaera represents the biggest emission of abiogenic methane on land discovered so far. Deep and pressurized gas accumulations are necessary to sustain the Chimaera gas flow for thousands of years and are likely to have been charged by an active inorganic source.

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Origin of hydrogen-nitrogen gas seeps, Oman

Cited by 58 publications

References 28 publications

Abiotic Methane on Earth

Abiotic Methane on Earth

A model for low‐temperature biogeochemistry of sulfur, carbon, and iron on Europa

New evidence for a mixed inorganic and organic origin of the Olympic Chimaera fire (Turkey): a large onshore seepage of abiogenic gas

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