Abiogenic methanogenesis in crystalline rocks

Lollar, Barbara Sherwood; Frape, Shaun K.; Weise, Stephan M.; Fritz, P.; Macko, Stephen A.; Welhan, J. A.

doi:10.1016/0016-7037(93)90610-9

Cited by 234 publications

(90 citation statements)

References 20 publications

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“…The impact-induced fracturing of the basement rock could have caused a 'pulse' of serpentinization to fuel early organic formation during the onset of the hydrothermal system. Empirical evidence for the production of hydrocarbons and organics through serpentinization has been presented for the crystalline rocks of the Canadian and Fennoscandian Shields (Sherwood Lollar et al 1993) and Conical Seamount in the Mariani forearc (Haggerty 1991;Haggerty & Fisher 1992). The production of hydrocarbons on fresh olivine surfaces cracked by volcanically induced expansion and contraction has been suggested (Tingle & Hochella 1993), indirectly supporting the notion of a role for impactinduced fracturing in providing surfaces for serpentinization and later hydrocarbon formation, although laboratory experiments simulating the volcanic process have been more equivocal (Tingle & Hochella 1993).…”

Section: Craters and The Origin Of Lifementioning

confidence: 96%

The origin and emergence of life under impact bombardment

Cockell

2006

Phil. Trans. R. Soc. B

100

104

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Craters formed by asteroids and comets offer a number of possibilities as sites for prebiotic chemistry, and they invite a literal application of Darwin's 'warm little pond'. Some of these attributes, such as prolonged circulation of heated water, are found in deep-ocean hydrothermal vent systems, previously proposed as sites for prebiotic chemistry. However, impact craters host important characteristics in a single location, which include the formation of diverse metal sulphides, clays and zeolites as secondary hydrothermal minerals (which can act as templates or catalysts for prebiotic syntheses), fracturing of rock during impact (creating a large surface area for reactions), the delivery of iron in the case of the impact of iron-containing meteorites (which might itself act as a substrate for prebiotic reactions), diverse impact energies resulting in different rates of hydrothermal cooling and thus organic syntheses, and the indiscriminate nature of impacts into every available lithologygenerating large numbers of 'experiments' in the origin of life. Following the evolution of life, craters provide cryptoendolithic and chasmoendolithic habitats, particularly in non-sedimentary lithologies, where limited pore space would otherwise restrict colonization. In impact melt sheets, shattered, mixed rocks ultimately provided diverse geochemical gradients, which in present-day craters support the growth of microbial communities.

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Section: Craters and The Origin Of Lifementioning

confidence: 96%

The origin and emergence of life under impact bombardment

Cockell

2006

Phil. Trans. R. Soc. B

100

104

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“…Thermogenic methane formed from the abiogenic alteration of sedimentary organic matter at elevated temperatures typically has an isotopic composition between -25 to -50‰. Sedimentary basins influenced by magmatic activity or deep-seated mantle degassing may also contain mantle derived methane with δ 13 C values between -20 to -10‰ (DES MARAIS et al, 1981;KELLEY and FRÜH-GREEN, 1999;SHERWOOD LOLLAR et al, 1993;WELHAN, 1988). Relative to biogenic and mantle-derived CH 4 , which are accompanied by low concentrations of C 2+ hydrocarbons, thermogenic gas may contain substantial concentrations of longer chained n-alkanes.…”

Section: Sources Of Carbon Compoundsmentioning

confidence: 99%

Geochemistry of low-molecular weight hydrocarbons in hydrothermal fluids from Middle Valley, northern Juan de Fuca Ridge

Cruse

Seewald

2006

Geochimica et Cosmochimica Acta

106

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Hydrothermal vent fluids from Middle Valley, a sediment-covered mid-ocean ridge on the northern Juan de Fuca Ridge, were sampled in July, 2000. Eight different vents with exit temperatures of 186 to 281°C were sampled from two areas of venting: the Dead Dog and ODP Mound fields. Fluids from the Dead Dog field are characterized by higher concentrations of ΣNH 3 and organic compounds (C 1 -C 4 alkanes, ethene, propene, benzene and toluene) compared with fluids from the ODP Mound field. The ODP Mound fluids, however, are characterized by higher C 1 /(C 2 +C 3 ) and benzene:toluene ratios than those from the Dead Dog field. The aqueous organic compounds in these fluids have been derived from both bacterial processes (methanogenesis in low-temperature regions during recharge) as well as from thermogenic processes in higher-temperature portions of the subsurface reaction zone. As the sediments undergo hydrothermal alteration, carbon dioxide and hydrocarbons are released to solution as organic matter degrades via a stepwise oxidation process. Compositional and isotopic differences in the aqueous hydrocarbons indicate that maximum subsurface temperatures at the ODP Mound are greater than those at the Dead Dog field. Maximum subsurface temperatures were calculated assuming that thermodynamic equilibrium is attained between alkenes and alkanes, benzene and toluene, and carbon dioxide and methane. The calculated temperatures for alkene-alkane equilibrium are consistent with differences in the dissolved Cl concentrations in fluids from the two fields, and indicate that subsurface temperatures at the ODP Mound are hotter than those at the Dead Dog field. Temperatures calculated assuming benzene-toluene equilibrium and carbon dioxide-methane equilibrium are similar to observed exit temperatures, and do not record the hottest subsurface conditions. The difference in subsurface temperatures estimated using organic geochemical thermometers reflects subsurface cooling processes via mixing of a hot, low-salinity vapor with a cooler, seawater salinity fluid. Because of the disparate temperature dependence of alkene-alkane and benzene-toluene equilibria, the mixed fluid records both the high and low temperature equilibrium conditions. These calculations indicate that vapor-rich fluids are presently being formed in the crust beneath the ODP Mound, yet do not reach the surface due to mixing with the lower-temperature fluids.2

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“…Biotic methanogenesis is usually associated with archaea, living under anaerobic conditions in wetlands, rice fields, landfills or the gastrointestinal tracts of ruminants and termites. Abiotic formation of CH 4 has been reported to occur under conditions that require high pressure and/or temperature, for instance, during biomass burning or serpentinization of olivine, under hydrothermal conditions in the oceans' depths or below tectonic plates [5][6][7] . In the chemical industry, CH 4 is often produced from carbon monoxide and hydrogen gas under elevated pressure and temperature (cf.…”

mentioning

confidence: 99%

Abiotic methanogenesis from organosulphur compounds under ambient conditions

et al. 2014

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Methane in the environment is produced by both biotic and abiotic processes. Biomethanation involves the formation of methane by microbes that live in oxygen-free environments. Abiotic methane formation proceeds under conditions at elevated temperature and/or pressure. Here we present a chemical reaction that readily forms methane from organosulphur compounds under highly oxidative conditions at ambient atmospheric pressure and temperature. When using iron(II/III), hydrogen peroxide and ascorbic acid as reagents, S-methyl groups of organosulphur compounds are efficiently converted into methane. In a first step, methyl sulphides are oxidized to the corresponding sulphoxides. In the next step, demethylation of the sulphoxide via homolytic bond cleavage leads to methyl radical formation and finally to methane in high yields. Because sulphoxidation of methyl sulphides is ubiquitous in the environment, this novel chemical route might mimic methane formation in living aerobic organisms.

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Abiogenic methanogenesis in crystalline rocks

Cited by 234 publications

References 20 publications

The origin and emergence of life under impact bombardment

The origin and emergence of life under impact bombardment

Geochemistry of low-molecular weight hydrocarbons in hydrothermal fluids from Middle Valley, northern Juan de Fuca Ridge

Abiotic methanogenesis from organosulphur compounds under ambient conditions

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