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A Nitrogen-Rich Metamorphic Fluid and Coexisting Minerals in Slates from North Wales

Published online by Cambridge University Press:  05 July 2018

S. H. Bottrell
Affiliation:
Department of Earth Sciences, University of Leeds, Leeds LS2 9JT
L. P. Carr
Affiliation:
Department of Earth Sciences, The Open University, Walton Hall, Milton Keynes, MK7 6AA
J. Dubessy
Affiliation:
Centre de Recherches sur la Geologie de l'Uranium, 3 rue du Bois de la Champelle, 54500 Vandœuvre-les-Nancy, France

Abstract

Volatile species analysis of fluid inclusions in metamorphic quartz veins from the Llanbedr Formation, North Wales, show nitrogen to be an important component. Microthermometric and Laser Raman analysis indicates that the N2 is resident in a generation of very N2-rich inclusions and demonstrates the presence of both N2-rich and aqueous fluids during metamorphism of the Llanbedr Formation. N2-rich fluids do not appear to have been present in adjacent lithologies. Isotopic analysis of N2 in fluid inclusions and in the slates indicates that the N2 in the slates (thought to be present as substituting for K+ in muscovite and for Na+ in ) was probably originally derived from organic matter in the sediment and subsequently released to the fluid phase during metamorphism.

Mineral-fluid and fluid-phase equilibrium calculations show that the mineral assemblage in the slates could be in equilibrium with either N2-rich or aqueous fluid depending on redox conditions. The N2-rich and aqueous fluids in the veins could, therefore, have been trapped at different times under different conditions, though their coexistence as immiscible fluids is a possibility.

Type
Petrology and Geochemistry
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1988

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References

Barker, D.S. (1964) Am. Mineral. 49, 58-15.Google Scholar
Bastoul, A. (1983) Ph.D. thesis, INPL Nancy.Google Scholar
Bottrelt, S.H. (1986) Ph.D. thesis, University of East Anglia.Google Scholar
Casquet, C. (1986) J. Metamorphic Geol. 4, 117-30.CrossRefGoogle Scholar
Chatterjee, N.D., and Johannes, W. (1974) Contrib. Mineral. Petrol. 48, 89-114.CrossRefGoogle Scholar
Dhamelincourt, P., Beny, J.M., Dubessy, J., and Poty, B. (1979) Bull. Mineral. 107, 155-68.Google Scholar
Dubessy, J., and Ramboz, C. (1986) Extended abstracts, WRI-5. 1714, Reykjavik.Google Scholar
Dubessy, J., and Ramboz, C. Geisler, D., Kosztolany, C., and Vernet, M. (1983) Geochim. Cosmochim. Acta, 47, 1-10.Google Scholar
Fettes, D.J., Long, C.B., Bevins, R.E., Max, M.D., Oliver, G.J.H., Primmer, T.J., Thomas, L.J., and Yardley, B.W.D. (1985) In Harris, A.L. (ed.) Memoir No. 9. The Geological Society, 41-53.CrossRefGoogle Scholar
Frost, B.R. (1985) J. Petrol. 26, 31-63.CrossRefGoogle Scholar
Haendel, D. Muhle, K., Nitzsche, H.-M., Stiehl, G., and Wand, U. (1986) Geochim. Cosmochim. Acta, 50, 749-58.Google Scholar
Hallam, M., and Eugster, H.P. (1976) Contrib. Mineral. Petrol. 57, 227-44.CrossRefGoogle Scholar
Harvey, P.K., Taylor, D.M., Hendry, R., and Bancroft, F. (1973) X-ray Spectrometry, 2, 33-44.CrossRefGoogle Scholar
Japas, M.L., and Franck, E.U. (1985) Ber. Bunsenges. Phys. Chem. 89, 793-800.CrossRefGoogle Scholar
Kreulen, R., and Schuiling, R.D. (1982) Geochim. Cosmochim. Acta, 46, 193-203.Google Scholar
Matley, C.A., and Wilson, T.S. (1943) Q.J. Geol. Soc. London, 102, 1-35.Google Scholar
Milovskiy, A.V., and Volynets, V.F. (1966) Geochem. Internat. 3, 75-28.Google Scholar
Norrish, K., and Hutton, J.T. (1969) Geochim. Cosmochim. Acta, 33, 431-53.Google Scholar
Ohmoto, H., and Kerrick, D. (1977) Am. J. Sci. 277, 101-344.CrossRefGoogle Scholar
Peters, K.E., Sweeney, R.E., and Kaplan, I.R. (1978) Limnol. Oceanogr. 23, 598-604.CrossRefGoogle Scholar
Ryzhenko, B.N., and Volkov, V.P. (1971) Geochem. lnternat. 8, 468-81.Google Scholar
Shepherd, T.J. (1981) Econ. Geol. 75, 1244-7.CrossRefGoogle Scholar
Shepherd, T.J. and Waters, P. (1984) Mineral. Deposita, 19, 304-14.Google Scholar
Shigorova, T.A., Kotov, N.V., Kotel'nikova, Ye. N., Schmakin, B.N., and Frank-Kamenetskiy, Va. (1982) Geochem. Internat. 18, 76-82.Google Scholar
Stevenson, F.J. (1962) Geochim. Cosmochim. Acta, 26, 797-809.Google Scholar
Stull, D.R., and Prophet, H. (1971) U.S. Dept. Commerce, Nat. Bur. Stds. 37.Google Scholar
Tissot, B.P., and Welte, D.W. (1978) Petroleum formation and occurrence. A new approach to oil and gas exploration. Springer-Verlag.Google Scholar
Touret, J. (1982) Chem. Geol. 37, 49-58.CrossRefGoogle Scholar
Vedder, W. (1965) Geochim. Cosrnochim. Acta, 29, 221-8.Google Scholar
Yamamoto, T., and Nakahira, M. (1966) Am. Mineral. 51, 177-58.Google Scholar