Hostname: page-component-cd9895bd7-gvvz8 Total loading time: 0 Render date: 2024-12-27T08:14:37.220Z Has data issue: false hasContentIssue false
  • English
  • Français

Distribution of the ammonium ion in pegmatites, aplites and their minerals from central northern Portugal

Published online by Cambridge University Press:  05 July 2018

A. Hall  and
A. M. R. Neiva
A. Hall
Affiliation:
Department of Geology, Royal Holloway and Bedford New College, Egham, Surrey TW20 0EX, UK
A. M. R. Neiva
Affiliation:
Department of Mineralogy and Geology, University of Coimbra, 3000 Coimbra, Portugal
Get access Rights & Permissions [Opens in a new window]

Abstract

The ammonium content of pegmatites, aplites and granites from Alijó-Sanfins, northern Portugal, averages 162, 109 and 159 ppm respectively. There is no systematic difference in the NH4/K ratio between these rocks, and the variation in their ammonium content is mainly due to variations in the amount of potassium minerals they contain. The K-feldspars have higher NH4+ contents than the muscovites, but lower NH4/K ratios. The preference of NH4+ for micas rather than feldspars is not as great as that shown by rubidium. The ammonium content of pegmatites in general is highly variable, and is largely determined by the nature of the granites with which they are associated.

Keywords

ammoniumpegmatiteaplitegranitePortugal
Type
Petrology and Experimental Studies
Information
Mineralogical Magazine , Volume 54 , Issue 376 , September 1990 , pp. 455 - 461
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1990

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Hall, A. (1987) The ammonium content of Caledonian granites. J. Geol. Soc. London, 144, 671-4.CrossRefGoogle Scholar
Hall, A. (1988) The distribution of ammonium in the granites of south-west England. Ibid. 145, 37-4l.CrossRefGoogle Scholar
Honma, H. and Itihara, Y. (1981) Distribution of ammonium in minerals of metamorphic and granitic rocks. Geochim. Cosmochim. Acta, 45, 983-8.CrossRefGoogle Scholar
Itihara, Y. and Honma, H. (1979) Ammonium in biotite from metamorphic and granitic rocks of Japan. Ibid. 43, 503-9.CrossRefGoogle Scholar
Jahns, R. H. and Burnham, C. W. (1969) Experimental studies of pegmatite genesis: I. A model for the derivation and crystallization of granitic pegmatites. Econ. Geol. 64, 843-64.CrossRefGoogle Scholar
Jahns, R. H. and Tuttle, O. F. (1963) Layered pegmatite-aplite intrusives. Mineralogical Society of America, Special Paper 1, 78-92.Google Scholar
Mann, L. T. (1963) Spectrophotometric determination of nitrogen in total micro-Kjeldahl digests. Anal. Chem. 35, 2179-82.CrossRefGoogle Scholar
Neiva, A. M. R. (1973) Geochemistry of the granites and their minerals from the central area of northern Portugal. Mere. Not. Mus. Lab. Mineral. Geol. Univ. Coimbra, 76, 1-43.Google Scholar
Neiva, A. M. R. (1974) Geochemistry of the aplites and their minerals of Central Northern Portugal. Corn. Serv. Geol. Portugal, 58, 211-37.Google Scholar
Neiva, A. M. R. (1975) Geochemistry of coexisting aplites and pegmatites and of their minerals from central northern Portugal. Chem. Geol. 16, 153-77.CrossRefGoogle Scholar
Neiva, A. M. R. (1977) Geochemistry of the pegmatites and their minerals from central northern Portugal. Anais Fac. Cienc. Univ. Porto, 60, 1-28.Google Scholar
Solomon, G. C. and Rossman, G. R. (1988) NH4 + in pegmatitic feldspars from the southern Black Hills, South Dakota. Amer. Min. 73, 818-21.Google Scholar
Stevenson, F. J. (1962) Chemical state of the nitrogen in rocks. Geochim. Cosmochim. Acta, 26, 797-809.CrossRefGoogle Scholar
Urano, H. (1971) Geochemical and petrological study on the origins of metamorphic rocks and granitic rocks by determination of fixed ammoniacal nitrogen. J. Earth Sci. Nagoya Univ. 19, 1-24.Google Scholar