Limited Fluid Transport from the Gneiss Core Toward the Schist Envelope of the Dome de L’agout, France

  • Ariejan Bos
  • Willem Duit
  • J. Ben H. Jansen
Part of the NATO ASI Series book series (ASIC, volume 281)

Abstract

The Dome de l’Agout consists mainly of gneisses and granites, mantled by low to medium grade micaschists with relatively large amounts of graphite. Kreulen and Schuiling (1982) observed high nitrogen contents in fluid inclusions, with the highest gas contents increasing with metamorphic grade. They suggested that the nitrogen was mantle derived and moved from the centre of the dome outwards. Duit et al. (1986) analyzed the ammonium- and rubidium-contents in biotite and muscovite fractions and they observed a negative correlation between the highest ammonium contents in both minerals and metamorphic grade (Figure 1). Bos et al, (in press) studied the partitioning of ammonium and potassium between synthetic phlogopite and a chloride vapour. The distribution coefficient of ammonium was determined to be larger than 1 at the PT-conditions of 2000 bars at 550 and 650·C. The distribution coefficient increases, although slightly, with temperature, indicating that nitrogen storage in biotite is a valid source for N2-gas in the lower crust (Bos et al., in press). In contrast to ammonium, rubidium contents increase in both micas with increasing metamorphic grade (Figure 2), pointing at a difference in behaviour and origin of the ions in the metamorphic rocks. Rubidium and ammonium both substitute for potassium in natural silicates.

Keywords

Fluid Inclusion Metamorphic Grade High Nitrogen Content Nitrogen Storage Natural Silicate 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

References

  1. Beswick AE (1973) An experimental study of alkali metal distributions in feldspars and micas. Geochim Cosmochim Acta 37:183–208.CrossRefGoogle Scholar
  2. Bos A, Duit W, Eerden A van der, Jansen JBH (in press) Nitrogen storage in biotite: Experimental study of the ammonium and potassium partitioning between 1M-phlogopite and vapour at 2 kb. Geochim Cosmochim Acta.Google Scholar
  3. Duit W, Jansen JBH, Breemen A van, Bos A (1986) Ammonium micas in pelitic rocks as exemplified by Dome de l’Agout (France). Amer J Sci 286:702–732.CrossRefGoogle Scholar
  4. Kreulen R, Schuiling RD (1982) N2-CH4-CO2 fluids during the formation of the Dome de l’Agout, France. Geochim Cosmochim Acta 46:193–203.CrossRefGoogle Scholar
  5. Volfinger M (1976) Effet de la température sur les distributions de Na, Rb et Cs entre la sanidine, la muscovite, la phlogopite et une solution hydrothermale sous une pression de 1 kbar. Geochim Cosmochim Acta 40:267–282.CrossRefGoogle Scholar

Copyright information

© Kluwer Academic Publishers 1989

Authors and Affiliations

  • Ariejan Bos
    • 1
  • Willem Duit
    • 1
  • J. Ben H. Jansen
    • 1
  1. 1.Department of Geochemistry and Experimental Petrology, Institute for Earth SciencesUniversity of UtrechtUtrechtThe Netherlands

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