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Ferrian high sanidine in a lamproite from Cancarix, Spain

Published online by Cambridge University Press:  05 July 2018

Kees Linthout
Affiliation:
Department of Petrology and Isotope Geology, Institute of Earth Sciences, Vrije Universiteit, De Boelelaan 1085, 1081 HV Amsterdam, The Netherlands
Wim J. Lustenhouwer
Affiliation:
Department of Petrology and Isotope Geology, Institute of Earth Sciences, Vrije Universiteit, De Boelelaan 1085, 1081 HV Amsterdam, The Netherlands

Abstract

Na-poor, Fe-bearing high sanidine from a lamproite near Cancarix (Spain) has 2Vα‖(010) = 37-43° and C2/m, a = 8.598(15), b = 13.050(26), c = 7.209(17) Å, β = 116.00(18)° V = 727(2) Å3. Rims of sanidine crystals against vugs contain up to 60 mole % KFeSi3O8 and up to 10 at.% Si and 6 at.% K above the stoichiometric requirement; otherwise, they have up to 4 mole % □Si4O8 and 3 mole % K2O.Si4O8 in solid solution. Their MgO content may reach 0.46 wt.%. The skeletons of mm sized blocky crystals (Baveno habit) indicate formation under moderate undercooling at temperatures not much above 725°C Feldspar formation was facilitated by a high diffusion rate due to low viscosity in a highly perpotassic melt, supersaturated by pressure release and diopside fractionation, upon extrusion of a huge volume of lava in a crater. After titanian potassium-richterite largely filled the interstices in the sanidine fabric, crystals of dalyite (K2ZrSi6O15) and Fe-rich rims of sanidine and amphibole crystals were formed from an increasingly hydrous, silicic, ferric, and peralkaline residual melt. High rate nonequilibrium crystallisation caused the incorporation of excess SiO2 and K2O in the defect structure of the sanidine. Retrograde boiling initiated the escape of volatiles, causing the quenching, by which the disordered structural state and the nonstoichiometric composition of the sanidine were preserved.

Type
Mineralogy
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1993

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References

Annersten, H. (1976) New Mössbauer data on iron in potash feldspar. NeuesJahrb. Mineral., Mh., 337-43.Google Scholar
Beaty, D. W. And Albee, A. L. (1980) Silica solid solution in natural plagioclase. Am. Mineral., 65, 6374.Google Scholar
Bertelman, D., FöSrtsch, E., and Wondratschek, H. (1985) On the annealing behaviour of sanidines: the exceptional case of Eifel sanidine megacrystals. NeuesJahrb Mineral., Abh., 152, 123–41.Google Scholar
Best, M. G., Henage, L. F., and Adams, J. A. S. (1968) Mica peridotite, wyomingite, and associated potassic igneous rocks in northeastern Utah. Am. Mineral., 55, 1041–8.Google Scholar
Carman, J. H. and Tuttle, O. F. (1963) Experimental verification of solid solution of excess silica in sanidine from rhyolites. Program G.S.A. Meeting New Orleans, 331.Google Scholar
Camichael, I. S. A. (1967) The mineralogy and petrology of the volcanic rocks from the Leucite Hills, Wyoming. Contrib. Mineral. Petrol., 15, 2466.Google Scholar
Coombs, D. S. (1954) Ferriferous orthoclase from Madagascar. Mineral. Mag., 30, 409–27.Google Scholar
Correns, C. W. (1968) Einfiihring in die Mineralogie, 2nd ed. Springer-Verlag, Berlin. 458 pp.Google Scholar
Dingwell, D. B. and Mysen, B. O. (1985) Effects of water and fluorine on the viscosity of albite melt at high pressure: a preliminary investigation. Earth Planet. Sci. Lett., 74, 266–74.Google Scholar
Faust, G. T. (1936) The fusion relations of ironorthoclase, with a discussion of the evidence of the existence of an iron-orthoclase molecule in feldspars. Am. Mineral., 21, 735–63.Google Scholar
Fenn, P. M. (1977) The nucleation and growth of alkafi feldspars from hydrous melts. Can. Mineral., 15, 135–61.Google Scholar
Ferguson, R. B., Ball, N. A., and Oerny, P. (1991) Structure refinement of an adularian end-member high sanidine from the Buck Claim pegmatite, Bernic Lake, Manitoba. Ibid., 29, 543-52.Google Scholar
Fuster, J. M., Gastesi, P., Sagredo, J., and Fermoso, M. L. (1967) Las rocas lamproiticas del S.E. de España. Estudios Geoldgicos, 23, 3549.Google Scholar
Hamilton, D. L. (1961) Nephelines as crystallisation temperature indicators. J. Geol., 69, 321–9.Google Scholar
Hautefeuille, P. and Perrey, A. (1888) Sur la préparation et les propriétés d'orthose ferrique. Compt. Rend. Acad. Sci. Paris, 107, 1150–52.Google Scholar
Ito, J. (1976) High temperature solvent growth of anorthite on the join CaAlzSieOs-SiO2. Contrib. Mineral. Petrol., 59, 187–94.Google Scholar
Kirkpatrick, R. J. (1975) Crystal growth from the melt: A review. Am. Mineral., 60, 798814.Google Scholar
Krauskopf, K. B. (1967) Introduction to geochemistry. McGraw-Hill Book Company, New York, 721 pp.Google Scholar
Kroll, H. and Ribbe, P. H. (1987) Determining (AI,Si) distribution and strain in alkali feldspars using lattice parameters and diffraction-peak positions: a review. Am. Mineral., 72, 491506.Google Scholar
Le Maitre, R. W. (1989) A classification of igneous rocks and glossary of terms: recommendations of the International Union of Geological Sciences Subcom-mission of the Systematics of Igneous Rocks. Black-well Scientific Publications, London. 193 pp.Google Scholar
Lindqvist, B. (1966) Hydrothermal synthesis studies of potash-bearing sequioxide-silica systems. Geol. Fören. Stockh. Förh., 88, 133–78.Google Scholar
Lindsley, D. H., Smith, D., and Haggerty, S. E. (1971) Petrography and mineral chemistry of a differentiated flow of Picture Gore basalt near Spray, Oregon. Carnegie Institution Washington Yearbook, 69, 264–90.Google Scholar
Linthout, K., Nobel, F., and Lustenhouwer, W. (1988) First occurrence of dalyite in extrusive rock. Mineral. Mag., 368, 705–8.Google Scholar
Longhi, J. and Hays, J. F. (1979) Phase equilibria and solid solution along the join CaAl2Si2O2-SiO2. Am. J. Sci., 279, 876–90.Google Scholar
Mitchell, R. H. and Bergman, S. C. (1991) Petrology of lamproites. Plenum Press, New York, 447 pp.Google Scholar
Mustart, D. A. (1969) Hydrothermal synthesis of large single crystals of albite and potassium feldspar. EOS, Trans. Am. Geophys. Union, 56, 1075.(Abstr.).Google Scholar
Mysen, B. O. (1983) The structure of silicate melts. Ann. Reviews Earth Planet. Sci., 11, 7597.Google Scholar
Nixon, P. H., Thirlwell, M. F., Buckley, F. and Davies, C. J. (1984) Spanish and Western Australian lamproites: aspects of whole rock geochemistry, pp. 285-96. In Kimberlites and related rocks (Kornprobst, J., ed.), Elsevier, Amsterdam.Google Scholar
Pentinghaus, H. and Doras, O. Ö. (1976) Strukturelle Zustäinde in Orhtoklasen yon Madagaskar. Fortschr. Mineral., 54, Bh. 1, 72-3.Google Scholar
Riebling, E. F. (1966) Structure of sodium aluminosili-cate melts containing at least 50 mole % SiOa at 1500°C J. Chem. Phys., 44, 2857–65.Google Scholar
Schairer, J. F. And Bowen, N. L. (1955) The system K2O-Al2O3-SiO2. Am. J. Sci., 253, 681746.Google Scholar
Smith, J. V. And Brown, W. L. (1988) Feldspar Minerals, I, Crystal structures, physical, chemical, and microtextural properties, 2nd ed. Springer Verlag, Berlin, 828 pp.Google Scholar
Smith, P. M. and Franks, P. C. (1986) Mg-rich hollow sanidine in partially melted granite xenoliths in mica peridotite at Rose dome, Woodson County, Kansas. Am. Mineral., 71, 6067.Google Scholar
Spencer, E. (1937) The potash-soda feldspars. I. Thermal stability. Mineral. Mag., 24, 453–94.Google Scholar
Su, S. C., Ribbe, P. H., and Bloss, F. D. (1986) Alkali feldspars: Structural state determined from composition and optic axial angle 2V. Am. Mineral., 71, 1285–96.Google Scholar
Tilley, C. E. (1954) Nepheline-alkali feldspar paragene-sis. Am. J. Sci., 252, 6575.Google Scholar
Venturelli, G., Di Batlislini, G., Crawford, A. J., Kogarko, L. N., Celestini, S. (1984) The ultrapotassic rocks from southeastern Spain. Lithos, 17, 3754.Google Scholar
Venturelli, G., Salvioli Marani, E., Foley, S. F., Capedri, S., and Crawford, A. J. (1988) Petrogenesis and conditions of crystallisation of Spanish lamproitic rocks. Can. Mineral., 26, 6779.Google Scholar
Wagner, C. and Velde, D. (1986) The mineralogy of K-richterite-bearing lamproites. Am. Mineral., 71, 1737.Google Scholar
Woensdregt van, C. F. (1982) Crystal morphology of monoclinic potassium feldspars. Zeits. Krist., 161, 1533.Google Scholar
Wones, D. R. and Appleman, D. E. (1961) X-ray crystallography and optical properties of synthetic monoclinic KFeSi3Os, iron-sandine. U.S.G.S. Prof. Paper, 424-C, 309-10.Google Scholar
Wones, D. R. and Appleman, D. E. (1963) Properties of synthetic triclinic KFeSi3Os, iron-microcline, with some observations on the iron-microcline ⇋ iron-sanidine transition. J. Petrol., 4, 131–7.Google Scholar
Woolley, A. R. and Platt, R. G. (1986) The mineralogy of nepheline syenite complexes from the northern part of the Chilwa Province, Malawi. Mineral. Mag., 50, 597611.Google Scholar