Skip to main content
×
Home
    • Aa
    • Aa

Melt segregation and magma flow in migmatites: implications for the generation of granite magmas

  • E. W. Sawyer (a1)
Abstract:
ABSTRACT:

To form a granite pluton, the felsic melt produced by partial melting of the middle and lower continental crust must separate from its source and residuum. This can happen in three ways: (1) simple melt segregation, where only the melt fraction moves; (2) magma mobility, in which all the melt and residuum move together; and (3) magma mobility with melt segregation, in which the melt and residuum move together as a magma, but become separated during flow. The first mechanism applies to metatexite migmatites and the other two to diatexite migmatites, but the primary driving forces for each are deviatoric stresses related to regional-scale deformation. Neither of the first two mechanisms generates parental granite magmas. In the first mechanism segregation is so effective that the resulting magmas are too depleted in FeOT, MgO, Rb, Zr, Th and the REEs, and in the second no segregation occurs. Only the third mechanism produces magmas with compositions comparable with parental granites, and occurs at a large enough scale in the highest grade parts of migmatite terranes, to be considered representative of the segregation processes occurring in the source regions of granites.

Copyright
Linked references
Hide All

This list contains references from the content that can be linked to their source. For a full set of references and notes please see the PDF or HTML where available.

C. A. R. Albuquerque 1971. Petrochemistry of a series of granitic rocks from Northern Portugal. GEOL SOC AM BULL 82, 2783–98.

C. A. R. Alburquerque 1978. Rare earth elements in ‘younger’ granites, northern Portugal. LITHOS 11, 219–29.

A. G. Arth & G. N. Hanson 1975. Geochemistry and origin of the early Precambrian crust of northeastern Minnesota. GEOCHIM COSMOCHIM ACTA 39, 197241.

A. A. Arzi 1978. Critical phenomena in the rheology of partly melted rocks. TECTONOPHYSICS 44, 173–84.

W. G Bagby , K. L. Cameron & M. Cameron 1981. Contrasting evolution of calc-alkali volcanic and plutonic rocks of western Chihuahua, Mexico. J GEOPHYS RES 86, 10, 402–10.

P. Barbey , J. M. Bertrand , S. Angoua & D. Dautel 1989. Petrology and U/Pb geochronology of the Telohat migmatites, Aleksod. Central Hoggar, Algeria. CONTRIB MINERAL PETROL 101, 207–19.

F. Barker , G. L. Farmer , R. A. Ayuso , G. Plafker & J. S. Lull 1992. The 50 Ma granodiorite of the eastern Gulf of Alaska: melting in an accretionary prism in the forearc. J GEOPHYS RES 97, 6757–78.

M. Brouand , G. Banzet & P. Barbey 1990. Zircon behaviour during crustal anatexis. Evidence from the Tibetan Slab migmatites (Nepal). J VOLCANOL GEOTHERM RES 44, 143–61.

M. Brown 1973. Definition of metatexis, diatexis and migmatite. PROC GEOL ASSOC 84, 371382.

M. Brown 1994. The generation, segregation, ascent and emplacement of granite magma: The migmatite-to-crustally-derived granite connection in thickened orogens. EARTH-SCI REV 36, 83130.

M. Brown , Y. A. Averkin , E. L. McLellan & E. W. Sawyer 1995. Melt segregation in migmatites. J GEOPHYS RES 100, 15, 655–79.

A. J. Calvert , E. W. Sawyer , W. J. Davis & J. N. Ludden 1995. Archaean subduction inferred from seismic images of a mantle suture in the Superior Province, NATURE 375, 670–4.

D. Castelli & B. Lombardo 1988. The Gophu La and western Lunana granites: Miocene muscovite leucogranites of the Bhutan Himalaya. LITHOS 21, 211–25.

J. D. Clemens & C. K. Mawer 1992. Granitic magma transport by fracture propagation. TECTONOPHYSICS 204, 339–60.

W. J. Collins , R. H. Flood , R. H. Vernon & S. E. Shaw 1989. The Wuluma granite, Arunta Block, central Australia: an example of in situ, near-isochemical granite formation in a granulite facies terrane. LITHOS 23, 6383.

M. B. Crawford & B. F. Windley 1990. Leucogranites of the Himalaya/Karakoram: implications for magmatic evolution within collisional belts and the study of collision related leucogranite genesis. J VOLCANOL GEOTHERM RES 44, 119.

M. J. Daines & F. M. Richter 1988. An experimental method for directly determining the interconnectivity of melt in a partially molten system. GEOPHYS RES LETT 15, 1459–62.

W. C. Day & P. W. Weblen 1986. Origin of Late Archaean granite: geochemical evidence from the Vermilion Granite Complex of northern Minnesota. CONTRIB MINERAL PETROL 93, 283–96.

L. N. Dell'Angelo & J. Tullis 1988. Experimental deformation of partially melted granitic aggregates. J METAMORPH GEOL 6, 495516.

R. S. D'Lemos , M. Brown & R. A. Strachan 1992. The relationship between granite and shear zones: magma generation, ascent and emplacement within a transpressional orogen. J GEOL SOC LONDON 149, 487–90.

L. N. Gupta & W. Johannes 1982. Petrogenesis of a stromatic migmatite (Nelaug, southern Norway). J PETROL 23, 548–67.

L. N. Gupta & W. Johannes 1985. Effect of metamorphism and partial melting of host rocks on zircons. J METAMORPH GEOL 3, 311–23.

B. Lapointe & E. H. Chown 1993. Gold-bearing iron-formation in a granulite terrane of the Canadian Shield: a possible deep-level expression of an Archean gold-mineralizing system. MINERAL DEPOSITA 28, 191–7.

N. Le Breton & A. B. Thompson 1988. Fluid-absent (dehydration) melting of biotite in metapelites in the early stages of crustal anatexis. CONTRIB MINERAL PETROL 99, 226–37.

S. Maaløe 1982. Geochemical aspects of permeability controlled partial melting and fractional crystallization. GEOCHIM COSMOCHIM ACTA 46, 4357.

H. Martin 1980. Comportement de quelques elements en traces au cours de l'anatexie. L'exemple du massif de Saint Malo (Bretagne, France). CAN J EARTH SCI 17, 927–41.

T. S. McCarthy & D. I. Groves 1979. The Blue Tier Batholith, Northeastern Tasmania. CONTRIB MINERAL PETROL 71, 193209.

D. McKenzie 1985. The extraction of magma from the crust and mantle. EARTH PLANET SCI LETT 74, 8191.

C. B. McKenzie & Clarke D. B. 1975. Petrology of the South Mountain Batholith, Nova Scotia. CAN J EARTH SCI 12, 1209–18.

A. Nédélec , D. Minyem & P. Barbey 1993. High–P–high–T anatexis of Archaean tonalitic grey gneisses: the Eseka migmatites, Cameroon. PRECAMBRIAN RES 62, 191205.

A. M. R. Neiva 1981. Geochemistry of hybrid granitoid rocks and their biotites from central northern Portugal and their petrogenesis. LITHOS 14, 149–63.

A. Nicolas , Cl. Freydier , M. Godard & A. Vauchez 1993. Magma chambers at oceanic ridges; how large? GEOLOGY 21, 53–6.

M. Obata , Y. Yoshimura , K. Nagakawa , S. Odawara & Y. Osanai 1994. Crustal anatexis and melt migrations in the Higo metamorphic terrane, west-central Kyushu, Kumamoto, Japan. LITHOS 32, 135–47.

J. A. Pearce , N. B. W. Harris & A. G. Tindle 1984. Trace element discrimination diagrams for the tectonic interpretation of granitic rocks. J PETROL 25, 956–83.

J. A. Percival 1990. Archean tectonic setting of granulite terranes of the Superior Province, Canada: a view from the bottom. In D. Vielzeuf & Ph. Vidal (eds) Granulites and crustal evolution, 171193. Amsterdam: Kluwer.

J. A. Percival 1991. Granulite-facies metamorphism and crustal magmatism in the Ashuanipi Complex, Quebec–Labrador, Canada. J PETROL 32, 1261–97.

N. Petford , R. C. Kerr & J. R. Lister 1993. Dike transport of granitoid magmas, GEOLOGY 21, 845–8.

G. Poli , C. Ghezzo & S. Conticelli 1989. Geochemistry of granitic rocks from the Hercynian Sardinia–Corsica batholith: implication for magma genesis. LITHOS 23, 247–66.

J. B. Reid , O. C. Evans & D. G. Fates 1983. Magma mixing in granitic rocks of the central Sierra Nevada, California. EARTH PLANET SCI LETT 66, 243–61.

E. H. Rutter & D. H. K. Neumann 1995. Experimental deformation study of partly molten Westerly granite under fluid-absent conditions, with implications for the extraction of granitic magmas. J GEOPHYS RES 100, 15, 697716.

J. Saavedra , J. Rossi de Toselli , A. Toselli & A. Garcia-Sanchez 1985. The origin of the two-mica granites of the Loma Pelada pluton. Tucuman, northwest Argentina. LITHOS 18, 179–85.

E. W. Sawyer 1987. The role of partial melting and fractional crystallization in determining discordant migmatite leucosome compositions. J PETROL 28, 445–73.

E. W. Sawyer 1991. Disequilibrium melting and the rate of meltresiduum separation during migmatisation of mafic rocks from the Grenville Front, Quebec. J PETROL 32, 701–38.

E. W. Sawyer 1994. Melt segregation in the continental crust. GEOLOGY 22, 1019–22.

E. W. Sawyer & S.-J. Barnes 1988. Temporal and compositional differences between subsolidus and anatectic migmatite leucosomes from the Quetico metasedimentary belt, Canada. J METAMORPH GEOL 6, 437–50.

E. W. Sawyer & K. Benn 1993. Structure of the high-grade Opatica Belt and adjacent low-grade Abitibi Subprovince, Canada: an Archaean mountain front. J STRUCT GEOL 15, 1443–58.

G. Stevens & J. D. Clemens 1993. Fluid-absent melting and the roles of fluids in the lithosphere: a slanted summary? CHEM GEOL 108, 117.

K. E. Stormgard 1973. Stress distribution during the formation of boudinage and pressure shadows. TECTONOPHYSICS 16, 215–48.

R. L. Torres-Roldan 1983. Fractionated melting of metapelite and further crystal-melt equilibria—the example of the Blanca Unit migmatite complex, north of Estepona (southern Spain). TECTONOPHYSICS 96, 95123.

D. Vielzeuf & J. R. Holloway 1988. Experimental determination of the fluid-absent melting relations in the pelitic system: consequences for crustal differentiation. CONTRIB MINERAL PETROL 98, 257–76.

V. J. Wall , J. D. Clemens & D. B. Clarke 1987. Models for granitoid evolution and source compositions. J GEOL 95, 731–49.

C Weber , P. Barbey , M. Cuney & H. Martin 1985. Trace element behaviour during migmatization: evidence for a complex melt—residuum—fluid interaction in the St. Malo migmatitic dome (France). CONTRIB MINERAL PETROL 90, 5262.

A. J. R. White 1966. Genesis of migmatites from the Palmer region of South Australia. CHEM GEOL 1, 165200.

A. J. R. White & B. W. Chappell 1977. Ultrametamorphism and granitoid genesis. TECTONOPHYSICS 43, 722.

A. J. R. White & B. W. Chappell 1990. Per migma ad magma downunder. GEOL J 25, 221–5.

D. L. Whitney & A. J. Irving 1994. Origin of K-poor leucosomes in a metasedimentary migmatite complex by ultrametamorphism, syn-metamorphic magmatism and subsolidus processes. LITHOS 32, 173–92.

S. M. Wickham 1987a. The segregation and emplacement of granitic melts. J GEOL SOC LONDON 144, 281–97.

S. M. Wickham 1987b. Crustal anatexis and granite petrogenesis during low-pressure regional metamorphism: the Trois Seigneurs Massif, Pyrenees, France. J PETROL 28, 127–69.

H. G. F. Winkler & H. von Platten 1961. Experimentelle Gesteinsmetamorphose—V. GEOCHIM COSMOCHIM ACTA 24, 250–9.

M. L. Williams , S. Hanmer , C. Kopf & M. Darrach 1995. Syntectonic generation and segregation of tonalitic melts from amphibolite dykes in the lower crust Striding–Athabasca mylonite zone, northern Saskatchewan. J GEOPHYS RES 100, 15 717–34.

Recommend this journal

Email your librarian or administrator to recommend adding this journal to your organisation's collection.

Earth and Environmental Science Transactions of The Royal Society of Edinburgh
  • ISSN: 1755-6910
  • EISSN: 1755-6929
  • URL: /core/journals/earth-and-environmental-science-transactions-of-royal-society-of-edinburgh
Please enter your name
Please enter a valid email address
Who would you like to send this to? *
×

Keywords:

Metrics

Full text views

Total number of HTML views: 0
Total number of PDF views: 11 *
Loading metrics...

Abstract views

Total abstract views: 107 *
Loading metrics...

* Views captured on Cambridge Core between September 2016 - 23rd September 2017. This data will be updated every 24 hours.