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Continuous out-of-sequence ductile thrusting in the Norwegian Caledonides

Published online by Cambridge University Press:  01 May 2009

A. H. N. Rice
A. H. N. Rice
Affiliation:
Geology Department, University College, Galway, Eire*
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Abstract

Peak metamorphic conditions (up to sillimanite grade) in a unit of rocks beneath the evolving Kalak Nappe Complex (Finnmarkian Caledonides) developed prior to its incorporation as a nappe within the complex. The presence of displacement textures in peak metamorphic por-phyroblasts indicates that they grew in a hydrostatic stress regime and thus that the emplacement of tectonically higher units caused little or no deviatoric stress in the footwall rocks except close to the thrust plane.

The developing geotherm in the incipient nappe was disrupted by the onset of thrusting (D2 deformation), which placed hot rocks on colder rocks. This led to the cessation of prograde metamorphism and accounts for the ubiquitous association of nappe emplacement and the meta morphic peak. Later deformation (D3/D4) occurred at lower grades (biotite/chlorite). Consideration of nappe translation rates and the likely erosion/cooling rates indicates that nappe movements must have occurred ‘continuously out-of-sequence’ within the Kalak Nappe Complex.

Type
Articles
Information
Geological Magazine , Volume 124 , Issue 3 , May 1987 , pp. 249 - 260
Copyright
Copyright © Cambridge University Press 1987

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References

Andèrsen, T. B., Hakon, A., Sturt, B. A., Pedersen, S. & Kjaesrud, K. 1982. Rb–Sr whole rock ages from Magerøy, North Norwegian Caledonides. Norsk Geologisk Tidsskrift 62, 79–85.Google Scholar
Bevins, R. E., Robinson, D., Gayer, R. A. & Allman, S. 1986. Low-grade metamorphism in the Caledonides of Finnmark, Norway. Norges geologiske Undersøkelse Bulletin 404, 31–42.Google Scholar
Butler, R. W. H. 1983. Balanced cross-sections and their implications for the deep structure of the northwest Alps. Journal of Structural Geology 5, 125–37.CrossRefGoogle Scholar
Chapman, T. J., Gayer, R. A. & Williams, G. D. 1985. Structural cross-sections through the Finnmark Caledonides and the timing of the Finnmarkian event. In The Caledonide Orogen–Scandinavia and Related Areas (ed. Gee, D. G., Sturt, B. A.), pp. 593–609. London: John Wiley.Google Scholar
Davis, D., Suppe, J. & Dahlen, F. A. 1983. Mechanics of fold and thrust belts and accretionary wedges. Journal of Geophysical Research 88B 1153–72.CrossRefGoogle Scholar
England, P. C. & Richardson, S. W. 1977. The influence of erosion upon the mineral facies of rocks from differing metamorphic environments. Journal of the Geological Society of London 134, 201–13.CrossRefGoogle Scholar
Ferguson, C. C. 1980. Displacement of inert mineral grains by growing porphyroblasts: A volume-balance constraint. Geological Society of America Bulletin 91, 541–4.2.0.CO;2>CrossRefGoogle Scholar
Ferguson, C. C., Harvey, P. K. & Lloyd, G. E. 1980. On the mechanical interaction between a growing por-phyroblast and its surrounding matrix. Contributions to Mineralogy and Petrology 75, 339–52.CrossRefGoogle Scholar
Gayer, R. A., Hayes, S. J. & Rice, A. H. N. 1985. The structural development of the Kalak Nappe Complex of Eastern and Central Porsangerhalvøya, Finnmark, Norway. Norges geologiske Undersøkelse Bulletin 400, 67–87.Google Scholar
Harvey, P. K. & Ferguson, C. C. 1973. Spherically arranged inclusions in post tectonic garnet porphyroblasts. Mineralogical Magazine 39, 85–8.CrossRefGoogle Scholar
Harvey, P. K., Ferguson, C. C., Lloyd, G. E. & Shaw, K. G. 1977. Arcuate cleavage zones adjacent to garnet porphyroblasts in a hornfelsed metagreywacke. Tectonophysics 39, 473–6.CrossRefGoogle Scholar
Haxby, W. F. & Turcotte, D. L. 1976. Stresses induced by the addition or removal of overburden and associated thermal effects. Geology 4, 181–4.2.0.CO;2>CrossRefGoogle Scholar
Milton, N. J. & Williams, G. D. 1981. The strain profile above a major thrust fault, Finnmark, North Norway. In Thrust and Nappe Tectonics (ed. McClay, K. R., Price, N. J.), pp. 235–9. Geological Society of London Special Publication no.9.Google Scholar
Muller, G. & Schneider, A. 1971. Chemistry and genesis of garnets in metamorphic rocks. Contributions to Mineralogy and Petrology 31, 178–200.CrossRefGoogle Scholar
Rhodes, S. & Gayer, R. A. 1977. Non-cylindrical folds, linear structures in the X-direction and mylonite developed during translation of the Caledonian Kalak Nappe Complex of Finnmark, Norway. Geological Magazine 114, 329–40.CrossRefGoogle Scholar
Rice, A. H. N. 1984 a. Metamorphic and structural dia-chroneity in the Finnmarkian nappes of north Norway. Journal of Metamorphic Geology 2, 219–36.CrossRefGoogle Scholar
Rice, A. H. N. 1984 b. The significance of a thrust fault lineation in the Kalak Nappe Complex of Finnmark. Norsk geologisk Tidsskrift 64, 173–80.Google Scholar
Rice, A. H. N. 1985. Staurolite growth and metamorphic zones in the Kalak Nappe Complex of N. E. Porsangerhalvøya, N. Norway. Lithos 18, 281–94.CrossRefGoogle Scholar
Roberts, D. & Andersen, T. B. 1985. Nordkapp: Beskrivelse til berggrunsgeologisk kartblad. Norges geologiske Undersøkelse Skrifter 61, 1–49.Google Scholar
Sturt, B. A., Pringle, I. R. & Ramsay, D. M. 1978. The Finnmarkian phase of the Caledonian orogeny. Journal of the Geological Society of London 135, 597–610.CrossRefGoogle Scholar
Thompson, A. B. & England, P. C. 1984. Pressure-temperature-time paths of regional metamorphism. II. Their inference and interpretation using mineral assemblages in metamorphic rocks. Journal of Petrology 25, 929–55.CrossRefGoogle Scholar
Townsend, C., Roberts, D., Rice, A. H. N. & Gayer, R. A. 1986. The Gaissa Nappe, Finnmark, North Norway: An example of a deeply eroded external imbricate zone within the Scandinavian Caledonides. Journal of Structural Geology 8, 431–40.CrossRefGoogle Scholar
Williams, G. D. 1978. Rotation of contemporary folds into the X direction during overthrust processes in Lakse-fjord, Finnmark. Tectonophysics 48, 29–40.CrossRefGoogle Scholar
Williams, G. D., Chapman, T. J. & Milton, N. J. 1984. Generation and modification of finite strain patterns by progressive thrust faulting in the Laksefjord Nappe. Tectonophysics 107, 177–86.CrossRefGoogle Scholar
Yardley, B. W. D. 1974. Porphyroblasts and ‘crystallization forces’: A discussion of some theoretical considerations. Geological Society of America Bulletin 85, 61–2.2.0.CO;2>CrossRefGoogle Scholar