skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Abiogenic methanogenesis in crystalline rocks

Abstract

Isotopically anomalous CH[sub 4]-rich gas deposits are found in mining sites on both the Canadian and Fennoscandian shields. With [delta][sup 13]C[sub CH4] values from -22.4 to -48.5% and [delta]D[sub CH4] values from -133 to -372%, these methane deposits cannot be accounted for by conventional processes for bacterial or thermogenic methanogenesis. Compositionally the gases are similar to other CH[sub 4]-rich gas occurrences found in Canadian and Fennoscandian shield rocks. However, the isotopically anomalous gases of this study are characterized by unexpectedly high concentrations of H[sub 2] gas, ranging from several volume percent up to 30 vol%. The H[sub 2] gases are consistently depleted in the heavy isotope, with [delta]D[sub H[sub 2]] values of -619 to -659%. [sup 3]He/[sup 4]He ratios in the range of 0.4 X 10[sup [minus]8] to 4.4 X 10[sup [minus]8] indicate that there is no resolvable component of mantle-derived He in these deposits. Based on these results a mantle-derived source for the C-bearing gases is unlikely. Several lines of evidence support an alternative abiogenic origin for the gases from Sudbury, Canada, and Juuka and Pori, Finland. The D-depleted H[sub 2] gas and calculated [Delta]D[sub (CH[sub 4]-H[sub 2]]) equilibration temperatures of 110-170[degrees]C at all three sites are in goodmore » agreement with results obtained for abiogenically produced CH[sub 4] and H[sub 2] in ophiolite sequences in Oman and the Philippines. Serpentinization and the hydration of ultramafic rocks are the proposed mechanisms for CH[sub 4] and H[sub 2] production in these ophiolite sequences. The widespread occurrence of serpentinized and altered ultramafic rocks at Juuka and at a number of other sites in both Canada and Finland implies that similar mechanisms may be involved in gas production at at least three sites on the shields. Abiogenic processes of CH[sub 4] production may be considerably more widespread than previously anticipated.« less

Authors:
;  [1];  [2];  [3];  [4];  [5]
  1. Univ. of Waterloo, Ontario (Canada)
  2. Institut fuer Hydrologie (G.S.F), Neuherberg (Germany)
  3. UFZ, Umweltforschungszentrum, Leipzig-Halle (Germany)
  4. Univ. of Virginia, Charlottesville, VA (United States)
  5. Idaho State Univ., Pacatello, ID (United States)
Publication Date:
OSTI Identifier:
5207917
Resource Type:
Journal Article
Journal Name:
Geochimica et Cosmochimica Acta; (United States)
Additional Journal Information:
Journal Volume: 57:23-24; Journal ID: ISSN 0016-7037
Country of Publication:
United States
Language:
English
Subject:
03 NATURAL GAS; HYDROGEN; ORIGIN; METHANE; NATURAL GAS DEPOSITS; CARBON 13; DEUTERIUM; HELIUM 3; HELIUM 4; IGNEOUS ROCKS; ISOTOPE RATIO; METAMORPHIC ROCKS; ALKANES; CARBON ISOTOPES; ELEMENTS; EVEN-EVEN NUCLEI; EVEN-ODD NUCLEI; GEOLOGIC DEPOSITS; HELIUM ISOTOPES; HYDROCARBONS; HYDROGEN ISOTOPES; ISOTOPES; LIGHT NUCLEI; MINERAL RESOURCES; NONMETALS; NUCLEI; ODD-ODD NUCLEI; ORGANIC COMPOUNDS; RESOURCES; ROCKS; STABLE ISOTOPES; 030200* - Natural Gas- Reserves, Geology, & Exploration

Citation Formats

Lollar, B S, Frape, S K, Weise, S M, Fritz, P, Macko, S A, and Welhan, J A. Abiogenic methanogenesis in crystalline rocks. United States: N. p., 1993. Web. doi:10.1016/0016-7037(93)90610-9.
Lollar, B S, Frape, S K, Weise, S M, Fritz, P, Macko, S A, & Welhan, J A. Abiogenic methanogenesis in crystalline rocks. United States. doi:10.1016/0016-7037(93)90610-9.
Lollar, B S, Frape, S K, Weise, S M, Fritz, P, Macko, S A, and Welhan, J A. Wed . "Abiogenic methanogenesis in crystalline rocks". United States. doi:10.1016/0016-7037(93)90610-9.
@article{osti_5207917,
title = {Abiogenic methanogenesis in crystalline rocks},
author = {Lollar, B S and Frape, S K and Weise, S M and Fritz, P and Macko, S A and Welhan, J A},
abstractNote = {Isotopically anomalous CH[sub 4]-rich gas deposits are found in mining sites on both the Canadian and Fennoscandian shields. With [delta][sup 13]C[sub CH4] values from -22.4 to -48.5% and [delta]D[sub CH4] values from -133 to -372%, these methane deposits cannot be accounted for by conventional processes for bacterial or thermogenic methanogenesis. Compositionally the gases are similar to other CH[sub 4]-rich gas occurrences found in Canadian and Fennoscandian shield rocks. However, the isotopically anomalous gases of this study are characterized by unexpectedly high concentrations of H[sub 2] gas, ranging from several volume percent up to 30 vol%. The H[sub 2] gases are consistently depleted in the heavy isotope, with [delta]D[sub H[sub 2]] values of -619 to -659%. [sup 3]He/[sup 4]He ratios in the range of 0.4 X 10[sup [minus]8] to 4.4 X 10[sup [minus]8] indicate that there is no resolvable component of mantle-derived He in these deposits. Based on these results a mantle-derived source for the C-bearing gases is unlikely. Several lines of evidence support an alternative abiogenic origin for the gases from Sudbury, Canada, and Juuka and Pori, Finland. The D-depleted H[sub 2] gas and calculated [Delta]D[sub (CH[sub 4]-H[sub 2]]) equilibration temperatures of 110-170[degrees]C at all three sites are in good agreement with results obtained for abiogenically produced CH[sub 4] and H[sub 2] in ophiolite sequences in Oman and the Philippines. Serpentinization and the hydration of ultramafic rocks are the proposed mechanisms for CH[sub 4] and H[sub 2] production in these ophiolite sequences. The widespread occurrence of serpentinized and altered ultramafic rocks at Juuka and at a number of other sites in both Canada and Finland implies that similar mechanisms may be involved in gas production at at least three sites on the shields. Abiogenic processes of CH[sub 4] production may be considerably more widespread than previously anticipated.},
doi = {10.1016/0016-7037(93)90610-9},
journal = {Geochimica et Cosmochimica Acta; (United States)},
issn = {0016-7037},
number = ,
volume = 57:23-24,
place = {United States},
year = {1993},
month = {12}
}