Abstract
The compressibilities of the three end-member feldspars have been determined between 1 bar and 50 kbar by single crystal X-ray diffraction techniques, using a Merrill-Bassett type diamond anvil cell with three crystals loaded simultaneously. Low albite (ordered aluminium-silicon distribution) and high sanidine (disordered Al-Si) show similar behaviour on compression, with bulk moduli (linear fit to volume-pressure data) of 0.70 and 0.67 Mbar respectively. The most compressible cell axis of all three feldspars studied is a, indicating that the major change in the feldspar framework with pressure is a shortening of the overall length of the “crankshaft chains” by reduction of T-O-T angles.
Anorthite shows anomalous behaviour in that we have observed a previously unreported reversible phase transition at a pressure between 25.5 and 29.5 kbar. This transition is marked by large discontinuities in the unit cell angles and a small decrease of 0.2 percent in the cell volume with increasing pressure. The high-pressure phase is less compressible than the low-pressure phase, the bulk moduli being 0.94 and 1.06 Mbar respectively. There was no evidence of a monoclinic to triclinic inversion in sanidine that was expected to occur between 20 and 30 kbar on the basis of previous work on intermediate alkali feldspars.
Similar content being viewed by others
References
Adams LH, Wiliamson ED (1923) The compressibility of minerals and rocks at high pressures. J Franklin Inst 195:475–529. Quoted in Smith JV (1974) Feldspar Minerals, Vol. 1, p 596. Springer-Verlag, New York
Adlhart W, Frey F, Jagodzinski H (1980) X-ray and neutron investigations of the P\(\bar 1\)-I\(\bar 1\) transition in pure anorthite. Acta Crystallogr A36:450–460
Berking B (1976) Die Verfeinerung der Kristallstruktur eines lunaren Plagiochlases, An90. Z Kristallogr 144:189–197
Brown WL, Openshaw RE, McMillan PF, Henderson CMB (1984) A review of the expansion behavior of alkali feldspars: coupled variations in cell parameters and possible phase transitions. Am Mineral 69:1058–1071
Carpenter MA, McConnell JDC, Navrotsky A (1985) Enthalpies of ordering in the plagioclase feldspar solid solution. Geochim Cosmochim Acta 49:947–966
Foit FF, Peacor DR (1973) The anorthite crystal structure at 410° C and 830° C. Am Mineral 58:665–675
Hamilton WC (1974) Angle settings for four-circle diffractometers. In: Ebers JA, Hamilton WC (Eds) International Tables for X-ray Crystallography, Vol. IV. Kynoch Press, Birmingham
Harlow GE, Brown GE (1980) Low albite: an X-ray and neutron diffraction study. Am Miner 65:986–995
Hazen RM (1976) Sanidine: Predicted and observed monoclinic-to-triclinic reversible transformations at high pressure. Science 194:105–107
Hazen RM (1977) Temperature, pressure, and composition: structurally analagous variables. Phys Chem Minerals 1:83–94
Hazen RM, Finger LW (1982) Comparative crystal chemistry. John Wiley and Sons, New York
Hazen RM, Prewitt CT (1977) Linear compressibilities of low albite: high pressure structural implications. Am Mineral 62:554–558
Henderson CMB (1979) An elevated temperature X-ray study of synthetic disordered Na-K alkali feldspars. Contrib Mineral Petrol 70:71–79
Hovis GL (1980) Angular relations of alkali feldspar series and the triclinic-monoclinic displacive transformation. Am Mineral 65:770–778
Kempster CJE, Megaw HD, Radoslovich EW (1962) The structure of anorthite, CaAl2Si2O8. I. Structure analysis. Acta Crystallogr 15:1005–1017
King H, Finger LW (1979) Diffracted beam crystal centering and its application to high-pressure crystallography. J Appl Crystallogr 12:374–378
Kirkpatrick RJ, Kinsey RA, Smith KA, Henderson DM, Oldifeld E (1985) High resolution solid-state sodium-23, aluminium-27, and silicon-29 nuclear magnetic resonance spectroscopic reconnaissance of alkali and plagioclase feldspars. Am Mineral 70:106–123
Kirkpatrick RJ, Carpenter MA, Yang WH, Montez B (1987) 29Si magic-angle NMR spectroscopy of low temperature ordered plagioclase feldspars. Nature 325:236–237
Kroll H, Ribbe PH (1983) Lattice parameters, composition and Al,Si order in alkali feldspars. In: Ribbe PH (Ed) Reviews in Mineralogy, Vol. 2, 2nd edition, Feldspar Mineralogy: 57–99
McConnell JDC (1965) Electron optical study of effects associated with partial inversion in a silicate phase. Philos Mag 11:1289–1301
McCormick T, Angel RJ, Hazen RM (1988) Compressibility of omphacite to 60 Kbar: Role of vacancies. (in prep.)
Megaw (1974) Tilts and tetrahedra in feldspars. In: WS MacKenzie, J Zussman (Eds), The Feldspars, p 87–113. University of Manchester Press
Ohashi Y, Finger LW (1974) Refinement of the crystal structure of sanidine at 25° C and 400° C. Carnegie Inst Washington Yearb 73:539–544
Ohashi Y, Finger LW (1975) An effect of temperature on the feldspar structure: crystal structure of sanidine at 800° C. Carnegie Inst Washington Year Book 74:569–572
Piermarini GJ, Block S, Barnett JD (1973) Hydrostatic limits in liquids and solids to 100 Kbar. J Appl Phys 44:5377–5382
Prewitt CT, Sueno S, Papike JJ (1976) The crystal structures of high albite and monalbite at high temperatures. Am Miner 61:1213–1225
Redfern SAT, Salje E (1987) Thermodynamics of plagioclase II: Temperature evolution of the spontaneous strain at the I\(\bar 1\)-P\(\bar 1\) phase transition in anorthite. Phys Chem Minerals 14:189–195
Salje E (1985) Thermodynamics of sodium feldspar I: Order parameter treatment and strain induced coupling effects. Phys Chem Minerals 12:93–98
Salje E (1987) Thermodynamics of plagioclase I: Theory of the P\(\bar 1\)-I\(\bar 1\) phase transition in anorthite and calcium rich plagioclases. Phys Chem Minerals 14:181–188
Salje E, Kuscholke B, Wruck B, Kroll H (1985) Thermodynamics of sodium feldspar II: Experimental results and numerical calculations. Phys Chem Minerals 12:99–107
Scambos TA, Smyth JR, McCormick TC (1987) Structure refinement of high sanidine from the upper mantle. Am Mineral 72:973–978
Smith JV, Artioli G, Kvick A (1986) Low albite, NaAlSi3O8: Neutron diffraction study of crystal structure at 13K. Am Mineral 71:727–733
Smyth JR (1986) Crystal structure refinement of a lunar anorthite, An94. Proc 17th Lunar Sci Conf, J Geophys Res 91:E91-E97
Smyth JR, Hatton CJ (1977) A coesite-sanidine grospydite from the Roberts-Victor kimberlite. Earth Planet Sci Lett 34:284–290
Stewart DB, von Limbach D (1967) Thermal expanison of low and high albite. Am Mineral 52:389–413
Swanson DK (1986) High temperature crystal chemical formalisms applied to K2Si4O9 and NaGaSi3O8. PhD thesis, State University of New York at Stony Brook, New York, USA
Wainwright JE, Starkey J (1971) A refinement of the structure of anorthite. Z Kristallogr 133:75–84
Wenk H-R, Kroll H (1984) Analysis of P\(\bar 1\), I\(\bar 1\) and C\(\bar 1\) plagioclase structures. Bull Mineral 107:467–487
Winter JK, Ghose S, Okamura FP (1977) A high-temperature study of the thermal expansion and the anisotropy of the sodium atom in low albite. Am Miner 62:921–931
Winter JK, Okamura FP, Ghose S (1979) A high temperature structural study of high albite, monalbite and the analbite-monalbite phase transition. Am Miner 64:409–423
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Angel, R.J., Hazen, R.M., McCormick, T.C. et al. Comparative compressibility of end-member feldspars. Phys Chem Minerals 15, 313–318 (1988). https://doi.org/10.1007/BF00311034
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF00311034