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| Titel |
Formation of hydrocarbons under upper mantle conditions: experimental view |
| VerfasserIn |
Anton Kolesnikov, Vladimir G. Kutcherov |
| Konferenz |
EGU General Assembly 2010
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 12 (2010) |
| Datensatznummer |
250038016
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| Zusammenfassung |
| Main postulates of the theory of abiogenic abyssal origin of petroleum have been
developed in the last 50 years in Russia and Ukraine. According to this theory,
hydrocarbon compounds were generated in the mantle and migrated through the deep
faults into the Earth’s crust. There they formed oil and gas deposits in any kinds of
rocks and in any kind of their structural positions. Until recently the main obstacle
to accept the theory was the lack of reliable and reproducible experimental data
confirming the possibility of the synthesis of complex hydrocarbon systems under
the mantle conditions. The results received in the last decade by different groups
of researchers from Russia, U.S.A. and China have confirmed the possibility of
generation of hydrocarbons from inorganic materials, highly distributed in the Earth’s
mantle, under thermobaric conditions of 70-250 km: 2 – 5 GPa and 1000-1500 K.
Experiments made in the CONAC chamber at pressures of 3-5 GPa and temperatures
of 1000-1500 K by Kutcherov et al. [1, 2] have demonstrated that the mixtures
of hydrocarbons with composition similar to natural hydrocarbon systems have
been received as a result of chemical reactions between CaCO3, FeO and H2O.
Methane formation from the same compounds was registered after heating up to
600-1500 K at pressures of 4-11 GPa in diamond anvil cells [4, 5, 6]. Influence of
oxidation state of carbon donor and cooling rate of the fluid synthesized at high
pressure were studied using different types of high pressure equipments. It was shown
that composition of the final hydrocarbon mixture depends on these parameters.
Experimental investigations of transformation of methane and ethane at 2-5 GPa and
1000-1500 K [3] confirmed thermodynamic stability of heavy hydrocarbons in the upper
mantle and showed the possibility of hydrocarbon chain growth even at oxidative
environment.
For development of the theory of abiogenic abyssal origin of petroleum it is necessary to
arrange a set of new experiments to understand the pathways of hydrocarbons formation,
influence of pressure, temperature, oxygen fugacity and chemical composition of the
environment on the content of the mantle fluid.
[1] Kutcherov, V. G., Bendeliani, N. A. Alekseev, V. A. & Kenney, J. F. Synthesis of
Hydrocarbons from Minerals at Pressures up to 5 GPa. Doklady Physical Chemistry, 387,
4–6, 328–330 (2002).
[2] Kenney, J. F., Kutcherov, V. G., Bendeliani, N. A. & Alekseev, V. A. The Evolution of
Multicomponent Systems at High Pressures: VI. The Thermodynamic Stability of the
Hydrogen-Carbon System: The Genesis of Hydrocarbons and the Origin of Petroleum. Proc.
Natl. Acad. Sci. U.S.A., 99, 10976-10981 (2002).
[3] Kolesnikov A., Kutcherov V. G. and Goncharov A. F. Methane-derived
hydrocarbons produced under upper-mantle conditions. Nature Geoscience, 2, 566 – 570
(2009).
[4] Scott H.P., Hemley R.J, Mao H. et al. Generation of methane in the Earth’s mantle: In
situ high pressure-temperature measurements of carbonate reduction, Proc. Natl. Acad. Sci.
U.S.A., 101 14023-14026 (2004).
[5] Chen J.Y., et al. Methane formation from CaCO3 reduction catalyzed by high
pressure. Chin. Chem. Lett., 19, 4, 475-478 (2008).
[6] Sharma A., Cody G. D., and Hemley R. J. In situ Diamond-anvil cell observations of
methanogenesis at high pressures and temperatures. Energy Fuels, 23, 11, 5571–5579 (2009). |
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