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Phengite geobarometry based on the limiting assemblage with K-feldspar, phlogopite, and quartz

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Abstract

Following and extending the early work of Velde (1965) the pressure-temperature dependence of the compositions of potassic white micas coexisting with K-feldspar, quartz, and phlogopite in the model system K2O-MgO-Al2O3-SiO2-H2O was investigated up to fluid pressures of 24 kbar by synthesis experiments. There is a strong, almost linear increase of the Si content per formula unit (p.f.u.) of phengite, ideally KAl2−xMgx[Al1−xSi3+xO10] (OH)2 with pressure, as well as a moderate decrease of Si (or x) with temperature. The most siliceous phengite with Si near 3.8 p.f.u. becomes stable near 20 kbar depending on temperature. However, contrary to Velde's assumption, these phengites coexisting with the limiting assemblage are invariably not of an ideal dioctahedral composition (as given by the above formula) but have total octahedral occupancies as high as about 2.1 p.f.u.

The stability field of the critical assemblage phengite — K-feldspar — phlogopite — quartz ranges, in the presence of excess H2O, from at least 350° C to about 700° C but has an upper pressure limit in the range 16–22 kbar, when K-feldspar and phlogopite react to form phengite and a K, Mg-rich siliceous fluid.

For the purpose of using these phase relationships as a new geobarometer for natural rocks, the influence of other components in the phengite (F, Fe, Na) is evaluated on the basis of literature data. Water activities below unity shift the Si isopleths of phengite towards higher pressures and lower temperatures, but the effects are relatively small. Tests of the new geobarometer with published analytical and PT data on natural phengite-bearing rocks are handicapped by the paucity of reliable values, but also by the obvious lack of equilibration of phengite compositions in many rocks that show zonation of their phengites or even more than one generation of potassic white micas with different compositions. From natural phengites that do not coexist with the limiting assemblage studied here but still with a Mg, Fe-silicate, at least minimum pressures can be derived with the use of the data presented.

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References

  • Althaus E, Karotke E, Nitsch KH, Winkler HGF (1970) An experimental re-examination of the upper stability limit of muscovite plus quartz. Neues Jahrb Mineral Monatsh 1970:325–336

    Google Scholar 

  • Beccaluva L, Macciotta GP, Messiga B, Piccardo GB (1979) Petrology of the blue-schists metamorphic ophiolites of the Montenotte Nappe (Western Liguria — Italy). Ofioliti 4:1–36

    Google Scholar 

  • Berman RG, Brown ThH (1985) Heat capacity of minerals in the system Na2O-K2O-CaO-MgO-FeO-Fe2O3-Al2O3 -SiO2-TiO2-H2O-CO2: representation, estimation, and high temperature extrapolation. Contrib Mineral Petrol 89:168–183

    Google Scholar 

  • Brown EH (1975) A petrogenetic grid for reactions producing biotite and other Al-Fe-Mg silicates in the greenschist facies. J Petrol 16:258–271

    Google Scholar 

  • Brown P, Essene EJ, Peacor DR (1978) The mineralogy and petrology of manganese-rich rocks from St. Marcel, Piedmont, Italy. Contrib Mineral Petrol 67:227–232

    Google Scholar 

  • Chatterjee ND, Johannes W (1974) Thermal stability and standard thermodynamic properties of synthetic 2M1-muscovite, KAl2[AlSi3O10(OH)2]. Contrib Mineral Petrol 48:89–114

    Google Scholar 

  • Chopin C (1984) Coesite and pure pyrope in high-grade blueschists of the Western Alps: a first record and some consequences. Contrib Mineral Petrol 86:107–118

    Google Scholar 

  • Chopin C, Maluski H (1980) 40Ar-39Ar dating of high pressure metamorphic micas from the Gran Paradiso Area (Western Alps): Evidence against the blocking temperature concept. Contrib Mineral Petrol 74:109–122

    Google Scholar 

  • Cimmino F, Messiga B (1979) I calcescisti del Gruppo di Voltri (Liguria Occidentale): Le variazioni compositionali del miche bianche in rapporto alla evoluzione tectonico-metamorfica alpina. Ofioliti 4:269–294

    Google Scholar 

  • Crowley MS, Roy R (1964) Crystalline solubility in the muscovite and phlogopite groups. Am Mineral 49:348–362

    Google Scholar 

  • Day HW (1973) The high temperature stability of muscovite plus quartz. Am Mineral 58:255–262

    Google Scholar 

  • Dietrich H (1983) Zur Petrologie und Metamorphose des Brennermesozoikums (Stubaier Alpen, Tirol). Tschermaks Mineral Petrogr Mitt 31:235–257

    Google Scholar 

  • Ernst WG (1963) Significance of phengitic micas from low-grade schists. Am Mineral 48:1357–1373

    Google Scholar 

  • Ernst WG, Dal Piaz GV (1978) Mineral parageneses of eclogitic rocks and related mafic schists of the Piemonte ophiolite nappe, Breuil-St. Jacques area, Italian Western Alps. Am Mineral 63:621–640

    Google Scholar 

  • Evans BW (1965) Application of a reaction rate method to the breakdown equilibria of muscovite and muscovite plus quartz. Am J Sci 263:647–667

    Google Scholar 

  • Frey M, Hunziker JC, O'Neil JR, Schwander HW (1976) Equilibrium-disequilibrium relations in the Monte Rosa Granite, Western Alps: Petrological, Rb-Sr and stable isotope data. Contrib Mineral Petrol 55:147–179

    Google Scholar 

  • Guidotti CV, Sassi FP (1976) Muscovite as a petrogenetic indicator mineral in pelitic schists. Neues Jahrb Mineral Abh 127:97–142

    Google Scholar 

  • Guidotti CV, Sassi FP (1986) Classification and correlation of metamorphic facies series by means of muscovite b 0 data from low-grade metapelites. Neues Jahrb Mineral Abh 153:363–380

    Google Scholar 

  • Halbach H, Chatterjee ND (1982) An empirical Redlich-Kwongtype equation of state for water to 1,000° C and 200 kbar. Contrib Mineral Petrol 79:337–345

    Google Scholar 

  • Harley SL, Green DH (1981) Petrogenesis of eclogite inclusions in the Moses Rock Dyke, Utah, USA. Tschermaks Mineral Petrogr Mitt 28:131–155

    Google Scholar 

  • Heinrich CA (1982) Kyanite-eclogite to amphibolite facies evolution of hydrous mafic and pelitic rocks, Adula Nappe, Central Alps. Contrib Mineral Petrol 81:30–38

    Google Scholar 

  • Hoschek G (1980) The effect of Fe-Mg substitution on phase relations in marly rocks of the Western Hohe Tauern (Austria). Contrib Mineral Petrol 75:123–128

    Google Scholar 

  • Huang WL, Wyllie PJ (1974) Melting relations of muscovite with quartz and sanidine in the K2O-Al2O3-SiO2-H2O system to 30 kilobars and an outline of paragonite melting relations. Am J Sci 274:378–395

    Google Scholar 

  • Katagas C, Baltatzis E (1980) Coexisting celadonitic muscovite and paragonite in chlorite zone metapelites. Neues Jahrb Mineral Monatsh 1980:206–214

    Google Scholar 

  • Lardeaux J-M, Gosso G, Kienast J-R, Lombardo B (1983) Chemical variations in phengitic mica of successive foliations within the eclogitic micaschists complex, Sesia-Lanzo Zone (Italy, Western Alps) Bull Mineral 106:673–689

    Google Scholar 

  • Lattard D (1974) Les roches du faciès vert dans la zone de Sesia-Lanzo, Alpes Italiennes. Thèse 3ème cycle, Laboratoire de Petrologie Université Paris VI

  • Massonne H-J (1986) Breakdown of K-feldspar+phlogopite to phengite+K, Mg-rich silicate melt under the metamorphic conditions of a subduction zone. Int Symp Exp Mineral Geochem, Nancy 1986, pp 97–98

    Google Scholar 

  • Massonne H-J, Schreyer W (1980) Erhöhung der Muscovitstabilität durch MgSi-Einbau im Bereich von 3 bis 35 kb 223-01. Fortschr Mineral 58 Beih 1:88–90

    Google Scholar 

  • Massonne H-J, Schreyer W (1985) Phengite barometry in assemblages with kyanite, Mg-rich silicates, and a SiO2 phase. Terra Cognita 5:432

    Google Scholar 

  • Massonne H-J, Schreyer W (1986) High-pressure syntheses and X-ray properties of white micas in the system K2O-MgO-Al2O3-SiO2-H2O. Neues Jahrb Mineral Abh 153:177–215

    Google Scholar 

  • Mather JD (1970) The biotite isograd and the lower greenschist facies in the Dalradian rocks of Scotland. J Petrol 11:253–275

    Google Scholar 

  • McDowell SD, Elders WA (1980) Authigenic layer silicate minerals in borehole Elmore 1, Salton Sea geothermal field, California, USA. Contrib Mineral Petrol 74:293–310

    Google Scholar 

  • Miller Chr (1977a) Chemismus und phasenpetrologische Untersuchungen der Gesteine aus der Eklogitzone des Tauernfensters, Österreich. Tschermaks Mineral Petrogr Mitt 24:221–277

    Google Scholar 

  • Miller Chr (1977b) Mineral parageneses recording the p, T history of Alpine eclogites in the Tauern Window, Austria. Neues Jahrb Mineral Abh 130:69–77

    Google Scholar 

  • Moore DE, Liou JG (1979) Mineral chemistry of some Franciscan blueschist facies metasedimentary rocks from the Diablo Range, California. Geol Soc Am Bull II, 90:1737–1781

    Google Scholar 

  • Němec D (1980) Fluorine phengites from tin-bearing orthogneisses of the Bohemian-Moravian Heights, Czechoslovakia. Neues Jahrb Mineral Abh 139:155–169 (1980)

    Google Scholar 

  • Powell R, Evans JA (1983) A new geobarometer for the assemblag ebiotite-muscovite-chlorite-quartz. J Metam Geol 1:331–336

    Google Scholar 

  • Råheim A (1975) Mineral zoning as a record of P,T history of Precambrian eclogites and schists in western Tasmania. Lithos 8:221–236

    Google Scholar 

  • Råheim A (1976) Petrology of eclogites and surrounding schists from the Lyell Highway — Collingwood River Area. J Geol Soc Aust 23:313–327

    Google Scholar 

  • Robert J-L (1976) Phlogopite solid solutions in the system K2O -MgO-Al2O3-SiO2-H2O. Chem Geol 17:195–212

    Google Scholar 

  • Robie RA, Bethke PM, Beardsley KM (1967) Selected X-ray crystallographic data molar volumes, and densities of minerals and related substances. Geol Surv Bull 1248

  • Robie RA, Hemingway BS, Fisher JR (1979) Thermodynamic properties of minerals and related substances at 298.15 K and 1 bar (105 Pascals) pressure and at higher temperatures. Geol Surv Bull 1452

  • Saliot P, Velde B (1982) Phengite compositions and post-nappe high-pressure metamorphism in the Pennine zone of the French Alps. Earth Planet Sci Lett 57:133–138

    Google Scholar 

  • Schreyer W, Massonne H-J, Chopin C (1987) Continental crust subducted to depths near 100 km: Implications for magma and fluid genesis in collision zones. In: Mysen BO (ed) Magmatic processes: Physicochemical principles. Geochem Soc Spec Publ 1 (in press)

  • Seifert F (1970) Low-temperature compatibility relations of cordierite in haplopelites of the system K2O-MgO-Al2O3-SiO2 -H2O. J Petrol 11:73–99

    Google Scholar 

  • Smith D, Zientek M (1979) Mineral chemistry and zoning in eclogite inclusions from Colorado Plateau diatremes. Contrib Mineral Petrol 69:119–131

    Google Scholar 

  • Sorensen SS (1986) Petrologic and geochemical comparison of the blueschist and greenschist units of the Catalina Schist terrane, Southern California. In: Evans BW, Brown EH (eds) Blueschists and eclogites. Geol Soc Am Mem 164:59–75

  • Spear FS, Selverstone J, Hickmott D, Crowley P, Hodges KV (1984) P-T paths from garnet zoning: A new technique for deciphering tectonic processes in crystalline terranes. Geology 12:87–90

    Google Scholar 

  • Stöckhert B (1985) Compositional control on the polymorphism (2M 1 -3 T) of phengitic white mica from high pressure parageneses of the Sesia Zone (lower Aosta valley, Western Alps, Italy). Contrib Mineral Petrol 89:52–58

    Google Scholar 

  • Storre B, Karotke E (1972) Experimental data on melting reactions of muscovite+quartz in the system K2O-Al2O3-SiO2-H2O to 20 kb water pressure. Contrib Mineral Petrol 36:343–345

    Google Scholar 

  • Velde B (1965) Phengite micas: Synthesis, stability, and natural occurrence. Am J Sci 263:886–913

    Google Scholar 

  • Velde B (1966) Upper stability of muscovite. Am Mineral 51:924–929

    Google Scholar 

  • Velde B (1967) Si+4 content of natural phengites. Contrib Mineral Petrol 14:250–258

    Google Scholar 

  • Wang Y, Fuh TM (1966) A re-examination of the hydrothermal breakdown of muscovite. Proc Geol Soc China 9:31–45

    Google Scholar 

  • Wones DR (1967) A low pressure investigation of the stability of phlogopite. Geochim Cosmochim Acta 31:2248–2253

    Google Scholar 

  • Yoder HS Jr, Eugster HP (1955) Synthetic and natural muscovites. Geochim Cosmochim Acta 8:225–280

    Google Scholar 

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Massonne, H.J., Schreyer, W. Phengite geobarometry based on the limiting assemblage with K-feldspar, phlogopite, and quartz. Contr. Mineral. and Petrol. 96, 212–224 (1987). https://doi.org/10.1007/BF00375235

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