Contributions to Mineralogy and Petrology

, Volume 87, Issue 1, pp 72–86 | Cite as

A geothermobarometric investigation of garnet peridotites in the Western Gneiss Region of Norway

  • L. G. MedarisJr.
Article
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Abstract

In the Western Gneiss Region of Norway are found numerous peridotite lenses which have been extensively recrystallized under amphibolite fades conditions during the Caledonian Orogeny. However, evidence for an earlier Caledonian high-pressure metamorphism has been recorded by abundant eclogite and granulite relicts within gneiss and by the presence of at least ten garnet perioditite bodies preserved within chlorite peridotites. Two garnet-bearing ultramafic assemblages have been recognized: olivine-orthopyroxene-clinopyroxene-garnet and olivine-ortho-pyroxene-pargasitic-amphibole-garnet.

Except for olivine, minerals in the garnet peridotites are compositionally zoned, with relatively uniform cores and compositional gradients generally confined to the outer 200 micrometers, or less, of grains. The most common zoning patterns at grain margins are an increase in Fe/Mg in garnet, an increase in Al2O3 in orthopyroxene, and a decrease in Na2O and Al2O3 in clinopyroxene, although there are exceptions to these patterns at two localities. These zoning patterns have developed mainly in response to cooling and decompression of the garnet peridotites.

Application of geothermometers and barometers to the garnet peridotites has yielded temperatures of 770–860° C and pressures of 30–43 kb for cores of grains and consistently lower temperatures and pressures for rims, except for peridotites on Oterøy, where there is an apparent temperature increase from cores to rims.

The petrologic and geothermobarometric evidence for most of the investigated garnet peridotites is compatible with their tectonic emplacement from the upper mantle into thickened continental crust during Caledonian collision of the Baltic and Greenland plates.

Keywords

Olivine Chlorite Continental Crust Na2O Orogeny 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.
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References

  1. Albee AL, Ray L (1970) Correction methods for electron probe microanalysis of silicates, oxides, carbonates, phosphates, and sulfates. Anal Chem 42:1408–1414Google Scholar
  2. Bence AE, Albee AL (1968) Empirical correction factors for the electron microanalysis of silicates and oxides. J Geol 76:382–403Google Scholar
  3. Brastad K (in press) Relations between anorthosites, eclogites and ultramafics in Bjorkedalen, western nNorway. In: Gee DG and Sturt BA (eds) The Caledonide Orogen-Scandinavian and Related Areas. Wiley, LondonGoogle Scholar
  4. Brueckner HK (1974) “Mantle” Rb/Sr and 87Sr/86Sr ratios for clinopyroxenes from Norwegian garnet peridotites and pyroxenites. Earth Planet Sci Lett 24:26–32Google Scholar
  5. Brueckner HK (1977a) A crustal origin for eclogites and a mantle origin for garnet peridotites: strontium isotopic evidence from clinopyroxenes. Contrib Mineral Petrol 60:1–15Google Scholar
  6. Brueckner HK (1977b) A structural, stratigraphic and petrologic study of anorthosites, eclogites, and ultramafic rocks and their country rocks, Tafjord area, western south Norway. Nor Geol Unders 332:1–53Google Scholar
  7. Brueckner HK (1979) Precambrian ages from the Geiranger-Tafjord-Grotli area of the Basal Gneiss Region, west Norway. Nor Geol Tidsskr 59:141–153Google Scholar
  8. Bryhni I (1966) Reconnaissance studies of gneisses, ultrabasites, eclogites, and anorthosites in outer Nordfjord, western Norway. Nor Geol Unders 241:1–68Google Scholar
  9. Carswell DA (1968a) Picritic magma — residual dunite relationships in garnet peridotite at Kalskaret near Tafjord, south Norway. Contrib Mineral Petrol 19:97–124Google Scholar
  10. Carswell DA (1968b) Possible primary upper mantle peridotite in Norwegian basal gneiss. Lithos 1:322–355Google Scholar
  11. Carswell DA (1973) Garnet pyroxenite lens within Ugelvik layered garnet peridotite. Earth Planet Sci Lett 20:347–352Google Scholar
  12. Carswell DA (1981) Clarification of the petrology and occurrence of garnet lherzolites, garnet websterites and eclogite in the vicinity of Rodhaugen, Almklovdalen, west Norway. Nor Geol Tidsskr 61:249–260Google Scholar
  13. Carswell DA, Gibb FGF (1980) The equilibration conditions and petrogenesis of European crustal garnet lherzolites. Lithos 13:19–29Google Scholar
  14. Carswell DA, Harvey MA, Al-Samman A (1982) The petrogenesis of garnetiferous peridotites and related rocks in the high grade gneiss complex of western Norway. Terra cognita, 2:p 327Google Scholar
  15. Carswell DA, Harvey MA (in press) The intrusive history and tectono-metamorphic evolution of the Basal Gneiss Complex in the Molde Fjord area, West Norway. In: Gee DG and Sturt BA (eds) The Caledonide Orogen — Scandinavian and Related Areas. Wiley, LondonGoogle Scholar
  16. Carswell DA, et al. (in press) Norwegian orthopyroxene eclogites: calculated equilibration conditions and petrogenetic implications. In: Gee DG and Sturt BA (eds) The Caledonide Orogen — Scandinavian and Related Areas. Wiley, LondonGoogle Scholar
  17. Clark SP, Ringwood AE (1964) Density distribution and constitution of the mantle. Rev Geophys 2:35–88Google Scholar
  18. Cuthbert SJ, Harvey MA, Carswell DA (1983) A tectonic model for the metamorphic evolution of the Basal Gneiss Complex, Western South Norway. J Met Geol 1:63–90Google Scholar
  19. Cordellier F, Boudier F, Boullier AM (1981) Structural study of the Almklovdalen peridotite massif (southern Tectonophysics 77:257–281Google Scholar
  20. Ellis DJ, Green DH (1979) An experimental study of the effect of Ca upon garnet-clinopyroxene Fe-Mg exchange equilibria. Contrib Mineral Petrol 71:13–22Google Scholar
  21. Eskola P (1921) On the eclogites of Norway. Skr Norske Vidensk — Akad i Oslo, Mat-Naturv Kl 8:1–118Google Scholar
  22. Evans BW, Trommsdorff V (1978) Petrogenesis of garnet lherzolite, Cima di Gagnone, Lepontine Alps. Earth Planet Sci Lett 40:333–348Google Scholar
  23. Griffin WL, Brueckner HK (1980) Caledonian Sm-Nd ages and a crustal origin for Norwegian eclogites. Nature 285:319–321Google Scholar
  24. Griffin WL, Qvale H (in press) Superferrian eclogites and the crustal origin of garnet peridotites, Almklovdalen, Norway. In: Gee DG and Sturt BA (eds) The Caledonide Orogen — Scandinavian and Related Areas. Wiley, LondonGoogle Scholar
  25. Griffin WL, et al. (in press) High-pressure metamorphism in the Scandinavian Caledonides. In: Gee DG and Sturt BA (eds) The Caledonian Orogen — Scandinavian and Related Areas. Wiley, LondonGoogle Scholar
  26. Harley SL, Green DH (1982) Garnet-orthopyroxene barometry for granulites and peridotites. Nature 300:697–701Google Scholar
  27. Jenkins DM (1981) Experimental phase relations of hydrous peridotites modelled in the system H2O-CaO-MgO-Al2O3-SiO2. Contrib Mineral Petrol 77:166–176Google Scholar
  28. Kawasaki T (1979) The thermodynamic analysis on the Fe-Mg exchange equilibrium between olivine and garnet: an application to the estimation of P-T relations of ultramafic rocks. J Jpn Assoc Mineral Petrol Econ Geol 74:395–405Google Scholar
  29. Krogh EJ (1977) Evidence for a Precambrian continent-continent collision in western Norway. Nature 267:17–19Google Scholar
  30. Krogh TE, Mysen BO, Davis GL (1974) A Paleozoic age for the primary minerals of a Norwegian eclogite. Ann Rev Geophys Lab Carnegie Inst Wash 73:575–576Google Scholar
  31. Lappin MA (1966) The field relationships of basic and ultrabasic masses in the basal gneiss complex of Stadlandet and Almklovdalen, Nordfjord, southwestern Norway. Nor Geol Tidsskr 46:439–496Google Scholar
  32. Lappin MA (1973) An unusual clinopyroxene with complex lamellar intergrowths from an eclogite in the Sunndal-Grubse ultramafic mass, Almklovdalen, Nordfjord, Norway. Mineral Mag 39:313–320Google Scholar
  33. Lappin MA (1974) Eclogites from the Sunndal-Grubse ultramafic mass, Almklovdalen, Norway and the T-P history of the Almklovdalen masses. J Petrol 15:567–601Google Scholar
  34. Lappin MA, Pidgeon RT, van Breemen O (1979) Geochronology of basal gneisses and magerite syenites of Stadlandet, west Norway. Nor Geol Tidsskr 59:161–181Google Scholar
  35. Lasaga AC (1983) Geospeedometry: an extension of geothermometry, p. 81–114. In: Saxena SK (ed) Kinetics and Equilibrium in Minerals Reactions: Springer-Verlag, New YorkGoogle Scholar
  36. Lasaga AC, Richardson SM, Holland HD (1977) The mathematics of cation diffusion and exchange between silicate minerals during retrograde metamorphism, p 353–388. In: Saxena SK, Bhattachanji S (eds) Energetics of Geological Processes. Springer-Verlag, New YorkGoogle Scholar
  37. Mearns EW, Lappin MA (1982) A Sm-Nd isotopic study of “internal” grey gneiss from Almklovdalen, western Norway. Terra cognita 2:324–325Google Scholar
  38. Medaris LG (1980) Petrogenesis of the Lien peridotite and associated eclogites, Almklovdalen, western Norway. Lithos 13:339–353Google Scholar
  39. Medaris LG, Wang HF (in press) Diffusion modeling of garnet zoning in the Almklovdalen peridotite, Norway and thermal modeling of Scadinavian Caledonide tectonics: EOSGoogle Scholar
  40. Mercy ELP, O'Hara MJ (1965a) Chemistry of some garnet-bearing rocks from south Norwegian peridotites. Nor Geol Tidsskr 45:323–332Google Scholar
  41. Mercy ELP, O'Hara MJ (1965b) Olivines and orthopyroxenes from garnetiferous peridotites and related rocks. Nor Geol Tidsskr 45:457–461Google Scholar
  42. Mori T, Green DH (1978) Laboratory duplication of phase equilibria observed in natural garnet lherzolites. J Geol 86:83–97Google Scholar
  43. Obata M, Thompson AB (1981) Amphibole and chlorite in mafic and ultramafic rocks in the lower crust and upper mantle. Contrib Mineral Petrol 77:74–81Google Scholar
  44. O'Hara MJ, Mercy ELP (1963) Petrology and petrogenesis of some garnetiferous peridotites. Trans R Soc Edinb 65:251–314Google Scholar
  45. O'Hara MJ, Richardson SW, Wilson G (1971) Garnet peridotite stability and occurrence in crust and mantle. Contrib Mineral Petrol 32:48–67Google Scholar
  46. O'Neill HSTC, Wood BJ (1979) An experimental study of partitioning between garnet and olivine and its calibration as a geothermometer. Contrib Mineral Petrol 70:59–70Google Scholar
  47. Perkins D, Newton RC (1980) The composition of coexisting pyroxenes and garnet in the system CaO-MgO-Al2O3-SiO2 at 900°-1,100°C and high pressures. Contrib Mineral Petrol 75:291–300Google Scholar
  48. Schmidt HH (1963) Petrology and structure of the Eiksundal eclogite complex, Hareidlandlet, Suunmore, Norway. Unpubl Ph.D. Thesis, Harvard Univ., pp 323Google Scholar
  49. Torundbakken BO, Ilebekk (in press) A compilation of radiometric age determinations from the Western Gneiss Region, south Norway. Nor Geol TidsskrGoogle Scholar
  50. Wells PRA (1977) Pyroxene thermometry in simple and complex systems. Contrib Mineral Petrol 62:129–139Google Scholar
  51. Wilson CR, Smith D (in press) Cooling rate estimates from mineral zonation — resolving power and applications. Proc Third Int Kimberlite ConfGoogle Scholar
  52. Wood BJ (1974) Solubility of alumina in orthopyroxene coexisting with garnet. Contrib Mineral Petrol 46:1–15Google Scholar

Copyright information

© Springer-Verlag 1984

Authors and Affiliations

  • L. G. MedarisJr.
    • 1
  1. 1.Department of Geology and GeophysicsUniversity of WisconsinMadisonUSA

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