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Serpentinization and the Formation of H2 and CH4 on Celestial Bodies (Planets, Moons, Comets).

Holm NG, Oze C, Mousis O, Waite JH, Guilbert-Lepoutre A - Astrobiology (2015)

Bottom Line: The continual and elevated production of H2 is capable of reducing carbon, thus initiating an inorganic pathway to produce organic compounds.The production of H2 and H2-dependent CH4 in serpentinization systems has received significant interdisciplinary interest, especially with regard to the abiotic synthesis of organic compounds and the origins and maintenance of life in Earth's lithosphere and elsewhere in the Universe.Whether deep in Earth's interior or in Kuiper Belt Objects in space, serpentinization is a feasible process to invoke as a means of producing astrobiologically indispensable H2 capable of reducing carbon to organic compounds.

View Article: PubMed Central - PubMed

Affiliation: 1 Department of Geological Sciences, Stockholm University , Stockholm, Sweden .

ABSTRACT
Serpentinization involves the hydrolysis and transformation of primary ferromagnesian minerals such as olivine ((Mg,Fe)2SiO4) and pyroxenes ((Mg,Fe)SiO3) to produce H2-rich fluids and a variety of secondary minerals over a wide range of environmental conditions. The continual and elevated production of H2 is capable of reducing carbon, thus initiating an inorganic pathway to produce organic compounds. The production of H2 and H2-dependent CH4 in serpentinization systems has received significant interdisciplinary interest, especially with regard to the abiotic synthesis of organic compounds and the origins and maintenance of life in Earth's lithosphere and elsewhere in the Universe. Here, serpentinization with an emphasis on the formation of H2 and CH4 are reviewed within the context of the mineralogy, temperature/pressure, and fluid/gas chemistry present in planetary environments. Whether deep in Earth's interior or in Kuiper Belt Objects in space, serpentinization is a feasible process to invoke as a means of producing astrobiologically indispensable H2 capable of reducing carbon to organic compounds.

No MeSH data available.


Related in: MedlinePlus

Central temperature of an Orcus-like object (radius of 500 km, density of 1.9 g/cm3) as a function of time after formation (no accretional heating is accounted for here). The dashed line highlights the melting point of water, while the solid lines give the evolution of the temperature (computed with the model by Guilbert-Lepoutre et al., 2011) under the influence of long-lived isotopes only (bottom curve) or both short- and long-lived isotopes (top curve, after a formation delay of 1 million years, which decreases the amount of short-lived nuclides). Other parameters of influence, like the thermal conductivity or composition, are within the range of realistic values used by other authors and similar to those used by Delsanti et al. (2010).
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f5: Central temperature of an Orcus-like object (radius of 500 km, density of 1.9 g/cm3) as a function of time after formation (no accretional heating is accounted for here). The dashed line highlights the melting point of water, while the solid lines give the evolution of the temperature (computed with the model by Guilbert-Lepoutre et al., 2011) under the influence of long-lived isotopes only (bottom curve) or both short- and long-lived isotopes (top curve, after a formation delay of 1 million years, which decreases the amount of short-lived nuclides). Other parameters of influence, like the thermal conductivity or composition, are within the range of realistic values used by other authors and similar to those used by Delsanti et al. (2010).

Mentions: The thermal evolution of larger objects is more complex. First, it involves two stages: an early evolution, dominated by the radioactive decay of short-lived nuclides 26Al and 60Fe, which should generate an intense but short heating. Whatever happens during this phase, long-lived isotopes 40K, 235U, 238U, and 232Th would inevitably decay over the age of the Solar System, generating a possible more moderate, but more extended, heating of KBO interiors during their late evolution (see the example in Fig. 5). McKinnon et al. (2008) found that KBOs with radii larger than 400 km would be the most affected by this late heating. Second, because these objects are larger and denser than comets, the possible production of an internal liquid phase might lead to a significant differentiation of their internal structure, local changes of composition or thermophysical parameters such as thermal conductivity, chemical reactions, or the triggering of processes such as cryovolcanism, which cannot be studied with the same models as those used for small comets. These models would, in this case, be very close to those used by the icy satellite community, and the results could be compared to those found for objects such as Enceladus, for example. Prialnik and Merk (2008) indeed studied the evolution of intermediate-sized objects (250 km radius), including KBOs and icy satellites, accounting for their growth phase and both early and late evolution; in all cases considered, the melting point of water ice was reached.


Serpentinization and the Formation of H2 and CH4 on Celestial Bodies (Planets, Moons, Comets).

Holm NG, Oze C, Mousis O, Waite JH, Guilbert-Lepoutre A - Astrobiology (2015)

Central temperature of an Orcus-like object (radius of 500 km, density of 1.9 g/cm3) as a function of time after formation (no accretional heating is accounted for here). The dashed line highlights the melting point of water, while the solid lines give the evolution of the temperature (computed with the model by Guilbert-Lepoutre et al., 2011) under the influence of long-lived isotopes only (bottom curve) or both short- and long-lived isotopes (top curve, after a formation delay of 1 million years, which decreases the amount of short-lived nuclides). Other parameters of influence, like the thermal conductivity or composition, are within the range of realistic values used by other authors and similar to those used by Delsanti et al. (2010).
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4523005&req=5

f5: Central temperature of an Orcus-like object (radius of 500 km, density of 1.9 g/cm3) as a function of time after formation (no accretional heating is accounted for here). The dashed line highlights the melting point of water, while the solid lines give the evolution of the temperature (computed with the model by Guilbert-Lepoutre et al., 2011) under the influence of long-lived isotopes only (bottom curve) or both short- and long-lived isotopes (top curve, after a formation delay of 1 million years, which decreases the amount of short-lived nuclides). Other parameters of influence, like the thermal conductivity or composition, are within the range of realistic values used by other authors and similar to those used by Delsanti et al. (2010).
Mentions: The thermal evolution of larger objects is more complex. First, it involves two stages: an early evolution, dominated by the radioactive decay of short-lived nuclides 26Al and 60Fe, which should generate an intense but short heating. Whatever happens during this phase, long-lived isotopes 40K, 235U, 238U, and 232Th would inevitably decay over the age of the Solar System, generating a possible more moderate, but more extended, heating of KBO interiors during their late evolution (see the example in Fig. 5). McKinnon et al. (2008) found that KBOs with radii larger than 400 km would be the most affected by this late heating. Second, because these objects are larger and denser than comets, the possible production of an internal liquid phase might lead to a significant differentiation of their internal structure, local changes of composition or thermophysical parameters such as thermal conductivity, chemical reactions, or the triggering of processes such as cryovolcanism, which cannot be studied with the same models as those used for small comets. These models would, in this case, be very close to those used by the icy satellite community, and the results could be compared to those found for objects such as Enceladus, for example. Prialnik and Merk (2008) indeed studied the evolution of intermediate-sized objects (250 km radius), including KBOs and icy satellites, accounting for their growth phase and both early and late evolution; in all cases considered, the melting point of water ice was reached.

Bottom Line: The continual and elevated production of H2 is capable of reducing carbon, thus initiating an inorganic pathway to produce organic compounds.The production of H2 and H2-dependent CH4 in serpentinization systems has received significant interdisciplinary interest, especially with regard to the abiotic synthesis of organic compounds and the origins and maintenance of life in Earth's lithosphere and elsewhere in the Universe.Whether deep in Earth's interior or in Kuiper Belt Objects in space, serpentinization is a feasible process to invoke as a means of producing astrobiologically indispensable H2 capable of reducing carbon to organic compounds.

View Article: PubMed Central - PubMed

Affiliation: 1 Department of Geological Sciences, Stockholm University , Stockholm, Sweden .

ABSTRACT
Serpentinization involves the hydrolysis and transformation of primary ferromagnesian minerals such as olivine ((Mg,Fe)2SiO4) and pyroxenes ((Mg,Fe)SiO3) to produce H2-rich fluids and a variety of secondary minerals over a wide range of environmental conditions. The continual and elevated production of H2 is capable of reducing carbon, thus initiating an inorganic pathway to produce organic compounds. The production of H2 and H2-dependent CH4 in serpentinization systems has received significant interdisciplinary interest, especially with regard to the abiotic synthesis of organic compounds and the origins and maintenance of life in Earth's lithosphere and elsewhere in the Universe. Here, serpentinization with an emphasis on the formation of H2 and CH4 are reviewed within the context of the mineralogy, temperature/pressure, and fluid/gas chemistry present in planetary environments. Whether deep in Earth's interior or in Kuiper Belt Objects in space, serpentinization is a feasible process to invoke as a means of producing astrobiologically indispensable H2 capable of reducing carbon to organic compounds.

No MeSH data available.


Related in: MedlinePlus