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Mössbauer and chemical investigations of mudrocks

Published online by Cambridge University Press:  09 July 2018

R. Davey
Affiliation:
The University of Sheffield, Western Bank, Sheffield S10 2TN
C. D. Curtis
Affiliation:
The University of Manchester, Manchester M13 9PL, UK

Abstract

The oxidation state and mineralogical distribution of Fe in two different shale sequences have been studied by Mössbauer spectroscopy and chemical methods. Kimmeridge Clay Formation sediments proved to be richer in total Fe than Gulf Coast shales. In such sediments, Fe may be present in clay minerals (Fe(II) in chlorite, Fe(III) in illite and illite/smectite), pyrite, and ferroan carbonates (siderite, dolomite and ankerite). Pyrite accounts for a much greater proportion of the total Fe in the Kimmeridge Clay samples in which it is difficult to reconcile chemical data with Mössbauer data. There is major doublet overlap of Fe(III) in silicates with Fe(II) in pyrite and spectra cannot be satisfactorily deconvoluted. This would appear to be a fundamental limitation for simple applications. In the pyrite-poor Gulf Coast material, however, chemical and spectroscopic evaluations of overall valence state are much more consistent. Confidence in both determinative techniques is generated, and useful information documenting progressive reduction and redistribution of Fe with burial is obtained.

Type
Research Article
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1989

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References

Bancroft, G.M. & Brown, J.R. (1975) A Mossbauer study of coexisting hornblendes and biotites: quantitative Fe3+/Fe2+ ratio. Am. Miner. 60, 265–272.Google Scholar
Beigheijn, L.Th. (1979) Determination of iron(II) in rock, soil and clay. Analyst 104, 1055–1061.Google Scholar
Bent, M.F., Persson, B.I. & Agresti, D.G. (1969) Least squares fitting program: Mossbauer computer analysis. Comp. Phy. Com. 67, 102–112.Google Scholar
Burst, J.F., (1959) Post diagenetic clay mineral–environmental relationships in the Gulf Coast Eocene. Clays Clay Miner. 6, 327–341.Google Scholar
Carothers, W.W. & Kharaka, Y.K., (1978) Aliphatic acid anions in oil-field waters: implications for origin of natural gas. Bull. Am. Ass. Petrol Geol. 62, 2441–2453.Google Scholar
Curtis, C.D. (1987) Inorganic geochemistry and petroleum exploration. Pp. 81140 in: Advances in Petroleum Geochemistry 2 (Brooks, J. & Welte, D., editors). Academic Press, London.Google Scholar
Davey, R.C., MacQuaker, J.H.S., Siddiqi, M., Curtis, C.D. & Williams, J. (1987) Applications of Mossbauer spectroscopy in the geochemistry of sedimentary rocks. Hyper. Inter. 41, 771–774.Google Scholar
Ericsson, T. & Wappling, R. (1976) Texture effects in 3/2-1/2 Mössbauer spectra. Colloque C6. J. Phys. 6, 719–723.Google Scholar
Foscolos, A.E. & Powell, T.G. (1979) Mineralogical and geochemical transformation of clays during burial diagenesis (catagenesis): relation to oil generation. Proc. Int. Clay Conf. Oxford, 261-270.Google Scholar
Heller-Kallai, L. & Rozenson, I. (1981) The use of Mossbauer spectroscopy of iron in clay mineralogy. Phys. Chem. Miner. 7, 223–238.CrossRefGoogle Scholar
Hogg, C.S. & Meads, R.E. (1970) The Mossbauer spectra of several micas and related minerals. Mineral. Mag. 37, 606–614.CrossRefGoogle Scholar
Hower, J., Eslinger, E.V., Hower, M.E. & Perry, E.A. (1976) Mechanism of burial metamorphism in argillaceous sediments: 1. Mineralogical and chemical evidence. Bull. Geol. Soc. Am. 87, 725–737.2.0.CO;2>CrossRefGoogle Scholar
Scotchman, I.C. (1984) Diagenesis of the Kimmeridge Clay Formation. PhD thesis, Univ. Sheffield, UK.Google Scholar
Surdam, R.C. & Crossey, L.J. (1985) Organic-inorganic reactions during progressive burial: key to porosity and permeability enhancement and preservation. Phil. Trans. R. Soc. London A315, 135156.Google Scholar