Abstract
Unit-cell parameters, c */b* ratios, Δbc values (Stewart and Ribbe, 1969), Or contents and the positions of two of the characteristic infared absorption bands are presented for 16 K-rich and for 5 Na-rich alkali feldspar samples. A more specific interpretation is given for the characteristic absorption bands. It is shown that the position of one of the infrared absorption bands depends on the degree of Al/Si order whereas the other depends both on the degree of Al/Si order and to a lesser degree on chemical composition.
It is recommended that a combination of X-ray and infrared data is useful in studying certain mineralogical and petrogenetic problems associated with the alkali feldspars.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Bahat, D.: Optical and infra-red studies on high-temperature alkali feldspars. J. Geol. Soc. Australia 17, 93–102 (1970)
Borg, I. Y., Smith, D. K.: Calculated X-ray powder patterns for silicate minerals. Geol. Soc. Am. Mem. 122 (1969)
Crosby, P.: Composition and structural state of alkali feldspars from charnockitic rocks on Whiteface Mountain, NewYork. Am. Mineralogist 56, 1788–1811 (1971)
Hafner, S., Laves, F.: Ordnung/Unordnung und Ultrarotabsorption. II. Variation der Lage und Intensität einiger Absorptionen von Feldspäten. Zur Struktur von Orthoklas und Adular. Z. Krist. 109, 204–225 (1957)
Iiishi, K., Tomisaka, T., Kato, T., Umegaki, Y.: Isomorphous substitution and infrared and far infrared spectra of the feldspar group. Neues Jahrb. Mineral., Abhandl. 115, 98–119 (1971)
Jones, J. B.: Order in alkali feldspars. Nature 210, 1352–1353 (1966)
Kracek, F. C., Neuvonen, K. J.: Thermochemistry of plagioclase and alkali feldspars. Am. J. Sci., Bowen Vol., 293–318 (1952)
Laves, F., Hafner, S.: Ordnung/Unordnung und Ultrarotabsorption. I. (Al, Si)-Verteilung in Feldspäten. Z. Krist. 108, 52–63 (1956)
Laves, F., Hafner, S.: Infrared absorption effects, nuclear magnetic resonance and structure of feldspars. Norsk Geol. Tidsskr. 42, Feldspar Vol., 57–71 (1962)
Lehtinen, M.: New evidence for an impact origin of Lake Lappajärvi, Western Finland. Bull. Geol. Soc. Finland 42, 89–93 (1970)
Lehtinen, M.: Lake Lappajärvi, a meteorite impact site in western Finland. (In preparation)
Liese, H. C.: Supplementary data on the correlation of infrared absorption spectra and the chemical composition of alkali feldspars. Appl. Spectry 24, 609–611 (1970)
Milkey, R. G.: Infrared spectra of some tectosilicates. Am. Mineralogist 45, 990–1007 (1960)
Orville, P. M.: Unit-cell parameters of the microcline-low albite and the sanidine-high albite solid solution series. Am. Mineralogist 52, 55–86 (1967)
Sahama, Th. G., Lehtinen, M.: Infrared absorption of melilite. C.R. Soc. géol. Finlande 38, 29–40 (1967)
Smith, J. V., MacKenzie, W. S.: Atomic, chemical and physical factors that control the stability of alkali feldspars. Inst. “Lucas Mallada”, Estud. Geol. Curs. Conf. 8, 53–69 (1961)
Stewart, D. B., Ribbe, P. H.: Structural explanation for variations in cell parameters of alkali feldspar with Al/Si ordering. Am. J. Sci., Sohairer Vol. 267-A, 444–462 (1969)
Wright, T. L., Stewart, D. B.: X-ray and optical study of alkali feldspar: I. Determination of composition and structural state from refined unit-cell parameters and 2 V. Am. Mineralogist 53, 38–87 (1968)
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Lehtinen, M. Degree of Al/Si order in potassium feldspars. A combination of X-Ray and infrared data. Contr. Mineral. and Petrol. 47, 223–230 (1974). https://doi.org/10.1007/BF00371542
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF00371542