Abstract
Island arcs, active and passive margins are the best tectonic settings to generate fertile reservoirs likely to be involved in subsequent granitoid genesis. In such environments, greywackes are abundant crustal rock types and thus are good candidates to generate large quantities of granitoid magmas. We performed a series of experiments, between 100 and 2000 MPa, on the fluid-absent melting of a quartz-rich aluminous metagreywacke composed of 32 wt% plagioclase (Pl) (An22), 25 wt% biotite (Bt) (X Mg45), and 41 wt% quartz (Qtz). Eighty experiments, averaging 13 days each, were carried out using a powder of minerals (≤5μm) and a glass of the same composition. The multivariant field of the complex reaction Bt+Pl+Qtz⇔Grt/Crd/Spl+ Opx+Kfs+melt limited by the Opx-in and Bt-out curves, is located between 810–860°C at 100 MPa, 800–850°C at 200 MPa, 810–860°C at 300 MPa, 820–880°C at 500 MPa, 860–930°C at 800 MPa, 890–990°C at 1000 MPa, and at a temperature lower than 1000°C at 1500 and 1700 MPa. The melting of biotite+plagioclase+ quartz produced melt+orthopyroxene (Opx) +cordierite (Crd) or spinel (Spl) at 100, 200 and 300 MPa, and melt+orthopyroxene+garnet (Grt) from 500 to 1700 MPa (+Qtz, Pl, FeTi Oxide at all pressures). K-feldspar (Kfs) was found as a product of the reaction in some cases and we observed that the residual plagioclase was always strongly enriched in orthoclase component. The P-T surface corresponding to the multivariant field of this reaction is about 50 to 100°C wide. At temperatures below the appearance of orthopyroxene, biotite is progressively replaced by garnet with increasing P. At 850°C, we observed that (1) the modal proportion of garnet increases markedly with P; (2) the grossular content of the garnet increases regularly from about 4 mol% at 500 MPa to 15 mol% at 2000 MPa. These changes can be ascribed to the reaction Bt+Pl+Qtz ⇔ Grt+Kfs+melt with biotite +plagioclase+quartz on the low-P side of the reaction. As a result, at 200 MPa, we observed the progressive disappearance of biotite without production of orthopyroxene. These experiments emphasize the importance of this reaction for the understanding of partial melting processes and evolution of the lower continental crust. Ca-poor Al-metagreywackes represent fertile rocks at commonly attainable temperatures (i.e. 800–900°C), below 700 MPa. There, 30 to 60 vol.% of melt can be produced. Above this pressure, temperatures above 900°C are required, making the production of granitoid magmas more difficult. Thin layers of gneisses composed of rothopyroxene, garnet, plagioclase, and quartz (±biotite), interbedded within sillimanite-bearing paragneisses, are quite common in granulite terrains. They may result from partial melting of metagreywackes and correspond to recrystallized mixtures of crystals (+trapped melt) left behind after removal of a major proportion of melt. Available experimental constraints indicate that extensive melting of pelites takes place at a significantly lower temperature (850°C±20) than in Al-metagreywackes (950°C±30), at 1000 MPa. The common observation that biotite is no longer stable in aluminous paragneisses while it still coexists commonly with orthopyroxene, garnet, plagioclase and quartz, provides rather tight temperature constraints for granulitic metamorphism.
Article PDF
Similar content being viewed by others
Avoid common mistakes on your manuscript.
Abbreviations
- Ab :
-
albite
- alm :
-
almandine component in garnet
- Als :
-
aluminum silicate
- An :
-
anorthite
- Ap :
-
apatite
- Bt :
-
biotite
- Cal :
-
calcite
- Crd :
-
cordierite
- Crn :
-
corundum
- En :
-
enstatite
- Fl :
-
fluid phase
- Fs :
-
ferrosilite
- Ged :
-
gedrite
- Gl :
-
glass
- Grs :
-
Grossular
- grs :
-
grossular component in garnet
- Grt :
-
garnet
- Hc :
-
hercynite
- Hem :
-
hematite
- Ilm :
-
ilmenite
- Kfs :
-
K-feldspar
- M :
-
melt
- Mag :
-
magnetite
- Ms :
-
muscovite
- Opx :
-
orthopyroxene
- Or :
-
orthoclase
- Phl :
-
phlogopite
- Pl :
-
plagioclase
- Po :
-
Pyrrhotite
- Prp :
-
pyrope
- prp :
-
pyrope component in garnet
- Otz :
-
quartz
- Rt :
-
rutile
- Sa :
-
sanidine
- Sil :
-
sillimanite
- Spl :
-
spinel
- St :
-
staurolite
- Ti-Mag :
-
titano-magnetite
- W :
-
water
References
Berman RG (1990) Mixing propeties of Ca−Mg−Fe−Mn garnets. Am Mineral 75:328–344
Berman RG, Brown TH, Greenwood HJ (1985) An internally consistent thermodynamic data base for minerals in the system Na2O−K2O−CaO−MgO−FeO−Fe2O3−Al2O3−SiO2−TiO2−H2O−CO2. Atomic Energy of Canada Ltd Technical Report 377
Bohlen SR, Bocttcher AL, Wall VJ, Clemens JD (1983) Stability of phlogopite-quartz and sanidine-quartz: a model for melting in the lower crust. Contrib Mineral Petrol 83:270–277
Chappell BW (1984) Source rocks of I- and S-type granites in the Lachlan Fold Belt, Southeastern Australia. Philos Trans R Soc London A310:693–707
Clemens JD (1984) Water contents of intermediate to silicic magmas. Lithos 11:213–287
Clemens JD, Vielzeuf D (1987) Constraints on melting and magma production in the crust. Earth Planet Sci Lett 86:287–306
Clemens JD, Wall VJ (1981) Crystallization and origin of some peraluminous (S-type) granitic magmas. Can Mineral 19:111–132
Clemens JD, Wall VJ (1984) Origin and evolution of a peraluminous silicic ignimbrite suite: the Violet Town Volcanics. Contrib Mineral Petrol 88:354–371
Conrad WK, Nicholls IA, Wall VJ (1988) Water-saturated and undersaturated melting of metaluminous and peraluminous crustal compositions at 10 kbar: evidence for the origin of silicic magmas in the Taupo Volcanic Zone, New Zealand, and other occurrences. J Petrol 29:765–803
Ebadi A, Johannes W (1991) Beginning of melting and composition of first melts in the system Qz−Ab−Or−H2O−CO2. Contrib Mineral Petrol 106:286–295
Eggler DH (1973) Principles of melting of hydrous phases in silicate melt. Carnegie Inst Washington Yearb 72:491–495
Eggler DH, Holloway JR (1977) Partial Melting of peridotite in the presence of H2O and CO2: principles and review. Magma genesis, Oregon Dept Geol Min Ind Bull 96:15–36
Eugster JP, Wones DR (1962) Stability relations of the ferruginous biotite, annite. J Petrol 3:82–125
Grant JA (1985) Phase equilibria in partial melting of pelitic rocks. In: Ashworth JR (ed) Migmatites. Glasgow, Blackie and Son, pp 86–144
Grant JA (1986) Quartz-phlogopite-liquid equilibria and origins of charnockites. Am Mineral 71:1071–1075
Griffin WL, Heier KS (1969) Parageneses of garnet in granulitefacies rocks, Lofoten-Vesteraalen, Norway. Contrib Mineral Petrol 23:89–116
Hoffer E, Grant JA (1980) Experimental investigation of the formation of cordierite-orthopyroxene parageneses in pelitic rocks. Contrib Mineral Petrol 73:15–22
Holdaway MJ (1980) Chemical formulae and activity models for biotite, muscovite and chlorite applicable to pelitic metamorphic rocks. Am Mineral 65:711–719
Hoschek G (1976) Melting relations of biotite + plagioclase + quartz. Neues Jahrb Mineral Monatsh 2:79–83
Johannes W (1984) Beginning of melting in the granite system Qz−Or−Ab−An−H2O. Contrib Mineral Petrol 86:264–273
Lasnier B, Leyreloup A, Marchand J (1973) Découverte d'un granite “charnockitique” au sein de “gneiss oeillés”: perspectives nouvelles sur l'origine de certaines leptynites du Massif Armoricain méridional (France). Contrib Mineral Petrol 41:131–144
Le Breton N, Thompson AB (1988) Fluid-absent (dehydration) melting of biotite in metapelites in the early stage of crustal anatexis. Contrib Mineral Petrol 99:226–237
Marignac C, Leroy J, Macaudiere J, Pichavant M, Weisbrod A (1980) Evolution tectonométamorphique d'un segment de l'orogène hercynien: les Cévennes médianes, Massif Central français. C R Acad Sci Paris 291:605–608
Miller CF (1985) Arc strongly peraluminous magmas derived from pelitic sedimentary sources? J Geol 93:673–689
Montana A, Brearley M (1989) An appraisal of the stability of phlogopite in the crust and the mantle. Am Mineral 74:1–4
Montel JM, Weber C, Pichavant M (1986) Biotite-sillimanitespinel assemblages in high-grade metamorphic rocks: occurrences, chemographic analysis and thermobarometric interest. Bull Mineral 109:555–573
Nekvasil H (1988) Calculated effect of anorthite component on the crystallization paths of H2O-undersaturated haplogranitic melts. Am Mineral 73:966–981
Nekvasil H, Burnham CW (1987) The calculated individual effects of pressure and water content on phase equilibria in the granite system. In: BO Mysen (ed) Magmatic processes: physicochemical principles. Geochem Soc Spec publ 1:433–445
Patiño Douce A, Johnston AD (1991) Phase equilibria and melt productivity in the pelitic system: implications for the origin of peraluminous granitoids and aluminous granulites. Contrib Mineral Petrol 107:202–218
Perkins III D, Holland TJB, Newton RC (1981) The Al2O3 contents of enstatite in equilibrium with garnet in the system MgO−Al2O3−SiO2 at 15–40 kbar and 900°–1110°C. Contrib Mineral Petrol 78:99–109
Perkins EH, Brown TH, Berman RG (1986) PTX-SYSTEM: three programs for calculation of pressure-temperature-composition phase diagrams. Comput Geosci 12:749–755
Peterson JW, Newton RC (1989) Reversed experiments on biotitequartz-feldspar melting in the KMASH: implications for crustal anatexis. J Geol 97:465–485
Pettijohn FJ (1963) “Data of geochemistry, chap. S., chemical composition of sandstones-excluding carbonate and volcanic sands”. US Geol Surv Prof Pap 440-S
Pin C, Duthou JL (1990) Sources of Hercynian granitoids from the French Massif Central: inferences from Nd isotopes and consequences for crustal evolution. Chem Geol 83:281–296
Pin C, Vielzeuf D (1983) Granulites and related rocks in Variscan median Europe: a dualistic interpretation. Tectonophysics 93:47–74
Robertson JK, Wyllie PJ (1971) Rock-water systems with special reference to the water-deficient region. Am J Sci 271:252–277
Rutter MJ, Wyllie PJ (1988) Melting of vapour-absent tonalite at 10 kbar to simulate dehydration-melting in the deep crust. Nature 331, 6152:159–160
Schmid R, Wood BJ (1976) Phase relationships in granulitic metapelites from the Ivrea-Verbano Zone (Northern Italy). Contrib Mineral Petrol 54:255–279
Seck HA (1971) Koexistierende Alkalifeldspäte und Plagioklase im System NaAlSi3O8−KalSi3O8−CaAl2Si2O8−H2O bei Temperaturen von 650°C bis 900°C. Neues Jahrb Mineral Abh 115:315–345
Segnit RA, Kennedy GC (1961) Reactions and melting relations in the system muscovite — quartz at high pressures. Am J Sci 259:280–287
Skjerlie KP, Johnston AD (1992) Vapor-absent melting at 10 kbar of a biotite- and amphibole-bearing tonalitic gneiss: implications for the generation of A-type granitcs. Geology 20:263–266
Skjerlie KP, Johnston AD (1994) Fluid-absent melting behaviour of a F-rich tonalitic gneiss at mid crustal pressures: implications for the generation of anorogenic granites. J Petrol (in press)
Thompson AB (1982) Dehydration melting of pelitic rocks and the generation of H2O-undersaturated granitic liquids. Am J Sci 282:1567–1595
Vielzeuf D, Clemens JD, Pin C, Moinet E (1990) Granites, granulites, and crustal differentiation. In: Vielzeuf D, Vidal Ph (eds) Granulites and crustal evolution, Kluwer academic publishers, Dordrecht Boston London, pp 59–85
Vielzcuf D, Clements JD (1992) The fluid-absent melting of phlogopite + quartz: experiments and models. Am Mineral 77:1206–1222
Vielzeuf D, Montel JM, Provost A, Kryza R (1991) The biotitegarnet — plagioclase — quartz assemblage as a potential geobarometer. EOS Trans Am Geophys Union 72, 44:559
Vielzeuf D, Holloway JR (1988) Experimental determination of the fluid-absent melting relations in the pelitic system. Contrib Mineral Petrol 98:257–276
Vielzeuf D (1984) Relations de phases dans le faciès granulite et implications géodynamiques. L'exemple des granulites des Pyrénées. Thèse Doctorat d'Etat, Clermont-Ferrand
Waters DJ (1988) Partial melting and the formation of granulite facies assemblages in Namaqualand, South Africa J Metamorphic Geol 6:387–404
Weber C, Barbey P (1986) The role of water, mixing processes and metamorphic fabric in the genesis of the Beaume migmatites (Ardèche, France). Contrib Mineral Petrol 92:481–491
Whetten JT, Kelley JC, Hanson LG (1969) Characteristics of Columbia River sediment and sediment transport. J Sediment Petrol 39:1149–1166
White AJR, Chappell BW (1988) Some supracrustal (S-type) granites of the Lachlan Fold Belt. Trans R Soc Edinburgh Earth Sci 79:169–181
Whitney JA (1975) The effects of pressure, temperature, and X H20 on phase assemblage in four synthetic rock compositions. J Geol 83:1–31
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Vielzeuf, D., Montel, J.M. Partial melting of metagreywackes. Part I. Fluid-absent experiments and phase relationships. Contr. Mineral. and Petrol. 117, 375–393 (1994). https://doi.org/10.1007/BF00307272
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF00307272