Skip to main content
SpringerLink
Log in

Dry granulite mineral assemblages in the contact aureoles of the Nain complex, Labrador

  • Published:
Contributions to Mineralogy and Petrology Aims and scope Submit manuscript

Abstract

Thermal aureoles surrounding intrusions of the Nain complex, Labrador, contain many unique or unusual mineral assemblages in aluminous gneisses and granulites, ironstones, and ultramafic rocks. Some of the limiting assemblages are (in addition to feldspars±pyrrhotite±ilmenite±graphite ±biotite±magnetite): Ga-Ol-Hy-Sp, Ga-Cd-Hy-Sp, Ga-Hy-Ol-Qz, Cd-Hy-Os-Qz, Ga-Cd-Sp-Si, Cd-Sp-Co-Si, Ga-Ol-Hy-Sp, Ga-Cd-Hy-Sp, Hy-Ol-Qz-Aug, and Ol-Hy-Sp(±Chl±Ca-amph±Aug). On the basis of some of these assemblages are (in addition to feldspars±pyrrhotite±ilmenite±graphite from 3.7–6.6 kbar and temperatures from 645–915 ° C. The paucity of hydrous phases, the preponderance of Ksp-Plag-Qz or even Cd-Ksp-Qz without evidence of a melt at these temperatures, the stable occurrence of osumilite, and the common presence of graphite suggest that \(P_{{\text{H}}_{\text{2}} {\text{O}}}\) was extremely low. The presence of graphite-pyrrhotite, the compositions of ilmenites, the compositions of coexisting Fe-Ti oxides, and other mineralogical data indicate the \(f_{{\text{O}}_{\text{2}} }\) was relatively low and, despite the wide range in bulk compositions and rock types, may have followed an approximately buffered trend. It is possible that the magmas of the Nain complex may have acted as an “external” \(f_{{\text{O}}_{\text{2}} }\) buffer for the aureole rocks. The unique nature of these mineral assemblages appears to be a function of the extremely low \(P_{{\text{H}}_{\text{2}} {\text{O}}}\).

This is a preview of subscription content, log in via an institution to check access.

Access this article

Log in via an institution

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Similar content being viewed by others

References

  • Barton, J.M., Jr.: Progress of isotopic and geochemical investigations, coastal Labrador. In: Nain Anorthosite Project, Labrador: Field Report 1973 (S.A. Morse, ed.), Univ. Massachusetts Contrib. 13, 18–28 (1974)

  • Berg, J.H.: Mineral assemblages in the contact aureole of the Hettasch intrusion and some P-T estimates for the emplacement of the Nain complex, coastal Labrador. Geol. Assn. Can.-Miner. Assn. Can. Program with Abstr. 8–9, 1974

  • Berg, J.H.: Aphebian metasedimentary and related rocks in the Snyder Bay-Avakutakh River area, Labrador. In: Nain Anorthosite Project, Labrador: Field Reprt 1975 (S.A. Morse, ed.), Univ. Massachusetts Contrib. 26, 7–19 (1976a)

  • Berg, J.H.: Mineralogy and petrology of the contact aureoles of the anorthositic Nain complex, Labrador. Unpubl. Ph.D. Thesis, Univ. Massachusetts, 1976b

  • Berg, J.H.: Metamorphosed mafic and ultramafic rocks in the contact aureoles of the Nain complex, Labrador, and the miscibility gap between spinel and magnetite in natural Cr-Al-Fe3+-Ti spinels. Geol. Soc. Am. Abstr. with Programs 8, 773–774 (1976c)

    Google Scholar 

  • Berg, J.H.: Regional geobarometry in the contact aureoles of the anorthositic Nain complex, Labrador. J. Petrol. (in press), 1977

  • Berg, J.H., Wheeler, E.P., II: Osumilite of deep-seated origin in the contact aureole of the anorthositic Nain complex, Labrador. Am. Mineralogist 61, 29–37 (1976)

    Google Scholar 

  • Brand, S.R.: Geology, petrology, and geochemistry of the Lower Kingurutik River area, Labrador, Canada. Unpubl. Ph.D. Thesis, Purdue University 1976

  • Bridgwater, D., Collerson, K.D., Hurst, R.W., Jesseau, C.W.: Field characteristics of the early Precambrian rocks from Saglek, coast of Labrador. Geol. Surv. Can., Paper 75-1, Part A, 287–296 (1975)

  • Buddington, A.F., Lindsley, D.H.: Iron-titanium oxide minerals and synthetic equivalents. J. Petrol. 5, 310–357 (1964)

    Google Scholar 

  • Chinner, G.A.: Pelitic gneisses with varying ferrous/ferric ratios from Glen Clova, Angus, Scotland. J. Petrol. 1, 178–217 (1960)

    Google Scholar 

  • Chinner, G.A.: Almandine in thermal aureoles. J. Petrol. 3, 316–340 (1962)

    Google Scholar 

  • Collerson, K.D., Jesseau, C.W., Bridgwater, D.: Crustal development of the Archaean gneiss complex: eastern Labrador. In: The Early History of the Earth (B.F. Windley, ed.), pp. 237–253. New York: Wiley 1976

    Google Scholar 

  • Davies, H.M.: Apatite from the Kiglapait layered intrusion, Labrador. EOS 55, 477 (1974)

    Google Scholar 

  • Emslie, R.F.: The Michikamau anorthositic intrusion, Labrador. Can. J. Earth Sci. 2, 385–399 (1965)

    Google Scholar 

  • French, B.M.: Some geologic implications of equilibrium between graphite and a C-H-O gas at high temperatures and pressures. Rev. Geophys. 4, 223–253 (1966)

    Google Scholar 

  • French, B.M.: Progressive contact metamorphism of the Biwabik Iron Formation, Mesabi Range, Minnesota. Minn. Geol. Surv. Bull. p. 45 (1968)

  • Fujii, T.: Solubility of Al2O3 in enstatite coexisting with forsterite and spinel. Yb. Carnegie Instn. Wash. 75, 566–571 (1976)

    Google Scholar 

  • Green, D.H., Ringwood, A.E.: An experimental investigation of the gabbro to eclogite transformation and its petrological applications. Geochim. Cosmochim. Acta 31, 767–833 (1967)

    Google Scholar 

  • Gustafson, W.I.: The stability of andradite, hedenbergite, and related minerals in the system Ca-Fe-Si-O-H. J. Petrol. 15, 455–496 (1974)

    Google Scholar 

  • Hensen, B. J.: Experimental study of the stability of cordierite and garnet in pelitic compositions at high pressures and temperatures. Unpubl. Ph.D. Thesis, Australian National University 1970

  • Holdaway, M.J., Lee, S.M.: Fe-Mg cordierite stability in high-grade pelitic rocks based on experimental, theoretical, and natural observations. (In press) 1977

  • Holdaway, M.J.: Fe-Mg cordierite stability in high-grade pelitic rocks based on experimental, theoretical, and natural observations. (In press) 1977

  • Kerrick, D.M.: Experimental determination of muscovite+quartz stability with PH2o<P Total. Am. J. Sci. 272, 946–958 (1972)

    Google Scholar 

  • Krogh, T.E., Davis, G.L.: The significance of inherited zircons on the age and origin of igneous rocks-an investigation of the ages of the Labrador adamellites. Yb. Carnegie Instn. Wash. 72, 610–613 (1973)

    Google Scholar 

  • Miyashiro, A.: Evolution of metamorphic belts. J. Petrol. 2, 277–311 (1961)

    Google Scholar 

  • Ramdohr, P.: Die Eisenerzlager des Oberharzer (Osteroeder) Diabaszuges und ihr Verhalten im Berich des Brockenkontakts. Neues Jahrb. Mineral. B.B. 55, 333–392 (1927)

    Google Scholar 

  • Robinson, P., Jaffe, H.W.: Aluminous enclaves in gedrite-cordierite gneiss from southwestern New Hampshire. Am. J. Sci. 267, 389–421 (1969)

    Google Scholar 

  • Schreyer, W., Seifert, F.: Metastability of an osumilite end member in the system K2O-MgO-Al2O3-SiO2-H2O and its possible bearing on the rarity of natural osumilites. Contrib. Mineral. Petrol. 15, 343–358 (1967)

    Google Scholar 

  • Seifert, F.: Stability of the assemblage cordierite+K feldspar+quartz. Contrib. Mineral. Petrol. 57, 179–185 (1976)

    Google Scholar 

  • Shido, F.: Plutonic and metamorphic rocks of the Nakoso and Iritono districs in the central Abukuma Plateau. J. Fac. Sci. Tokyo Univ., Sec. II, 11, 131–217 (1958)

    Google Scholar 

  • Smith, D.: Stability of the assemblage iron-rich orthopyroxene-olivine-quartz. Am. J. Sci. 271, 370–382 (1971)

    Google Scholar 

  • Smith, D.: Pyroxene-olivine-quartz assemblages in rocks associated with the Nain anorthosite massif, Labrador. J. Petrol. 15, 58–78 (1974)

    Google Scholar 

  • Speer, J.A.: The contact metamorphic aureole of the Kiglapait intrusion. In: Nain Anorthosite Project, Labrador: Field Report 1974 (S.A. Morse, ed.), Univ. Massachusets Contrib. 17, 16–26 (1975)

  • Speer, J.A.: The stratigraphy and metamorphism of the Snyder Group, Labrador. Unpubl. Ph.D. Thesis, Virginia Polytechnic Institute and State University 1976

  • Taylor, F.C.: Reconnaissance geology of a part of the Precambrian Shield, northeastern Quebec and Northern Labrador; Part II. Geol. Surv. Can., Paper 70-24, 1–10 (1970)

    Google Scholar 

  • Taylor, F.C.: A revision of Precambrian structural provinces in northeastern Quebec and northern Labrador. Can. J. Earth Sci. 8, 579–584 (1971)

    Google Scholar 

  • Tilley, C.E.: Contact metamorphism in the Comrie area of the Perthshire Highlands. Quart. J. Geol. Soc. Lond. 80, 22–70 (1924)

    Google Scholar 

  • Wheeler, E.P., II: Adamellite intrusive north of Davis Inlet, Labrador. Bull. Geol. Soc. Am. 66, 1031–1060 (1955)

    Google Scholar 

  • Wheeler, E.P., II.: Anorthosite-adamellite complex of Nain, Labrador. Bull. Geol. Soc. Am. 71, 1755–1762 (1960)

    Google Scholar 

Download references

Author information

Authors and Affiliations

  1. Department of Geology, Northern Illinois University, 60115, DeKalb, Illinois, USA

    Jonathan H. Berg

Authors
  1. Jonathan H. Berg
    View author publications

    You can also search for this author in PubMed Google Scholar

Rights and permissions

Reprints and permissions

About this article

Cite this article

Berg, J.H. Dry granulite mineral assemblages in the contact aureoles of the Nain complex, Labrador. Contr. Mineral. and Petrol. 64, 33–52 (1977). https://doi.org/10.1007/BF00375284

Download citation

  • Received:

  • Accepted:

  • Issue Date:

  • DOI: https://doi.org/10.1007/BF00375284

Keywords

Search

Navigation