Hostname: page-component-7479d7b7d-c9gpj Total loading time: 0 Render date: 2024-07-11T23:25:09.937Z Has data issue: false hasContentIssue false
  • English
  • Français

Derivation of 500 Ma eclogites from the passive margin of Baltica and a note on the tectonometamorphic heterogeneity of eclogite-bearing crust

Published online by Cambridge University Press:  01 May 2009

Per-Gunnar Andréasson  and
Lena Albrecht
Per-Gunnar Andréasson
Affiliation:
Department of Mineralogy & Petrology, Institute of Geology, University of Lund, Sölvegatan 13, S-223 62 Lund, Sweden
Lena Albrecht
Affiliation:
Department of Mineralogy & Petrology, Institute of Geology, University of Lund, Sölvegatan 13, S-223 62 Lund, Sweden
Get access Rights & Permissions [Opens in a new window]

Abstract

Several recent plate reconstructions of the Iapetus Ocean describe the margins of Baltica as passive until Silurian collision with Laurentia. Yet there is a variety of evidence to suggest that the accretion of the Scandinavian Caledonides began by latest Cambrian—early Ordovician subduction and imbrication of the passive continental margin. One such evidence is provided by eclogites occurring in the Seve Nappe Complex. Previous work by others dated the high-pressure metamorphism at 503±14 Ma (Sm—Nd garnet-omphacite age), and the uplift through the c. 500°C isotherm at 491±8 Ma (40Ar/39 Ar hornblende plateau ages). The protolith dolerites of the eclogites have been correlated with Iapetan rift-facies dolerites of the Baltoscandian margin. If valid, such a correlation implies early Caledonian destruction of the margin, and thus modification of those plate reconstructions which require passive margins around Baltica in latest Cambrian-early Ordovician time. This paper provides a substantially improved basis for the concept that the protoliths of eclogites and their host rocks derived from Baltoscandian rift basins. The chemical similarity between coronitic dolerites and dolerites of the rift basins pertains not only to element concentrations and variations but also to the specific T-MORB signature shared by the two groups. The variation of psammitic and pelitic schists, graphitic schists, calc-silicate gneisses and marbles of the eclogite host rocks equates with sequences of sandstones, siltstones, shales, black shale, quartzite, dolomite and limestones of Baltoscandian palaeobasins.

At the same time, the paper calls attention to the remarkable preservation of structural and metamorphic contrasts within the eclogite-bearing thrust sheets of the Seve Nappe Complex. Such disequilibrium is generally ascribed to the kinetics of localized deformation and fluid infiltration into dry crust. This paper presents evidence that disequilibrium is found also within inferred subducted sedimentary complexes, which are generally assumed to be pervasively flushed by fluids. Preservation of sedimentary, volcanic and magmatic structures and fabrics, and of both undeformed dolerite dykes and eclogitized dykes demonstrates that neither deformation nor high-pressure metamorphism were pervasive.

Type
Research Article
Information
Geological Magazine , Volume 132 , Issue 6 , November 1995 , pp. 729 - 738
Copyright
Copyright © Cambridge University Press 1995

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Andréasson, P. G., 1986. The Sarektjåkkå Nappe, Seve terranes of the northern Swedish Caledonides. Geologiska Föreningens i Stockholm Förhandlingar 108, 261–3.CrossRefGoogle Scholar
Andréasson, P. G., 1994. The Baltoscandian Margin in Neoproterozoic — Early Palaeozoic time. Some constraints on terrane derivation and accretion in the Arctic Scandinavian Caledonides. Tectonophysics 231, 1–32.CrossRefGoogle Scholar
Andréasson, P. G., Gee, D. G., Solyom, Z., & Widmark, T., 1983. Origin of high-P metamorphism in the Scandes. Terra Cognita 3, 182.Google Scholar
Andreasson, P. G., Gee, D. G., & Sukotjo, S., 1985. Seve eclogites in the Norrbotten Caledonides. In The Caledonide Orogen — Scandinavia and Related Areas (eds Gee, D. G. and Sturt, B. A.), pp. 887–902. Chichester: John Wiley and Sons.Google Scholar
Andréasson, P. G., Svenningsen, O., Johansson, I., Solyom, Z., & Xiaodan, T., 1992. Mafic dyke swarms of the Baltica—Iapetus transition, Seve Nappe Complex of the Sarek Mts., Swedish Caledonides. Geologiska Föreningens i Stockholm Förhandlingar 114, 31–45.CrossRefGoogle Scholar
Austrheim, H., 1986/1987. Eclogitization of lower crustal granulites by fluid migration through shear zones. Earth and Planetary Science Letters 81, 221–32.CrossRefGoogle Scholar
Austrheim, H., & Griffin, W. L., 1985. Shear deformation and eclogite formation within granulite-facies anorthosites of the Bergen Arcs, Western Norway. Chemical Geology 50, 267–81.CrossRefGoogle Scholar
Boundy, T. M., Fountain, D. M., & Austrheim, H., 1992. Structural development and petrofabrics of eclogite facies shear zones, Bergen Arcs, western Norway: implications for deep crustal deformation processes. Journal of Metamorphic Geology 10, 127–46.CrossRefGoogle Scholar
Bryhni, I., 1988. Early Palaeozoic metamorphism in the Scandinavian Caledonides. In The Caledonian-Appalachian Orogen (eds Harris, A. L. and Fettes, D. J.), pp. 135–40. Geological Society Special Publication no. 38.Google Scholar
Claesson, S., 1976. The age of the Ottfjället dolerites of the Särv Nappe, Swedish Caledonides. Geologiska Föreningens i Stockholm Förhandlingar 98, 370–4.CrossRefGoogle Scholar
Claesson, S. R., & Roddick, J. C., 1983. Ar40/Ar39 data on the age and metamorphism of the Ottfjället dolerites, Särv Nappe, Swedish Caledonides. Lithos 16, 61–73.CrossRefGoogle Scholar
Dallmeyer, R. D., Andréasson, P. G., & Svenningsen, O. M., 1991. Early tectonothermal evolution of the Scandinavian Caledonides: constraints from Ar40/Ar39 mineral ages within the Seve terranes of the Sarek Mts., north Sweden. Journal of Metamorphic Geology 9, 203–18.CrossRefGoogle Scholar
Dallmeyer, R. D., & Gee, D. G., 1986. Ar40/Ar39 mineral dates from retrogressed eclogites within the Baltoscandian miogeocline: Implications for a polyphase Caledonian orogenic evolution. Geological Society of America Bulletin 97, 26–34.2.0.CO;2>CrossRefGoogle Scholar
Dewey, J. F., Ryan, P. D., & Andersen, T. B., 1993. Orogenic uplift and collapse, crustal thickness, fabrics and metamorphic phase changes: the role of eclogites. In Magmatic Processes and Plate Tectonics (eds Prichard, H. M., Alabaster, T., Harris, N. B. W. and Neary, C. R.), pp. 325–43. Geological Society Special Publication no. 76.Google Scholar
Furnes, H., Nystuen, J. P., Brunfelt, A. O., & Solheim, S., 1983. Geochemistry of Upper Riphean—Vendian basalts associated with the ‘sparagmites’ of southern Norway. Geological Magazine 120, 349–61.CrossRefGoogle Scholar
Gee, D. G., 1987. The Scandinavian alum shales — Mid Cambrian to Tremadoc deposition in response to early Caledonian subduction. Norsk Geologisk Tidsskrift 67, 233–5.Google Scholar
Kullerud, K., Stephens, M. B., & Zachrisson, E., 1990. Pillow lavas as protoliths for eclogites: evidence from a late Precambrian—Cambrian continental margin, Seve Nappes, Scandinavian Caledonides. Contributions to Mineralogy and Petrology 105, 1–10.CrossRefGoogle Scholar
Kulling, O., 1982. Översikt över södra Norrbottens Kaledonidberggrund. Sveriges Geologiska undersökning, Serie Ba 26, 1–295.Google Scholar
Kumpulainen, R., & Nystuen, J. P., 1985. Late Proterozoic basin evolution and sedimentation in the westernmost part of Baltoscandia. In The Caledonide Orogen — Scandinavia and Related Areas (eds Gee, D. G. and Sturt, B. A.), pp. 213–32. Chichester: John Wiley and Sons.Google Scholar
Le Roex, A. P., Dick, H. J. B., Reid, A. M., Frey, F. A., Erlank, A. J., & Hart, S. R., 1985. Petrology and geochemistry of basalts from the American—Antarctic Ridge, Southern Ocean: implications for the westward influence of the Bouvet mantle plume. Contributions to Mineralogy and Petrology 90, 361–80.CrossRefGoogle Scholar
McKerrow, W. S., Dewey, J. F., & Scotese, C. R., 1991. The Ordovician and Silurian development of the Iapetus Ocean. Special Papers in Palaeontology 44, 165–78.Google Scholar
Mørk, M. B. E., 1985 a. Incomplete high P—T metamorphic transitions within the K vamsøy pyroxenite complex, west Norway: a case study of disequilibrium. Journal of Metamorphic Geology 3, 245–64.CrossRefGoogle Scholar
Mørk, M. B. E., 1985 b. A gabbro to eclogite transition on Flemsøy, Sunmøre, western Norway. Chemical Geology 50, 283–310.CrossRefGoogle Scholar
Mørk, M. B. E., Kullerud, K., & Stabel, A., 1988. Sm—Nd dating of Seve eclogites, Norrbotten, Sweden — Evidence for early Caledonian (505 Ma) subduction. Contributions to Mineralogy and Petrology 99, 344–51.CrossRefGoogle Scholar
Nystuen, J. P., 1982. Late Proterozoic basin evolution on the Baltoscandian craton: the Hedmark Group, southern Norway. Norges Geologiske Undersøkelse 375, 1–74.Google Scholar
Nystuen, J. P., 1987. Synthesis of the tectonic and sedimentological evolution of the late Proterozoic—early Cambrian Hedmark Basin, the Caledonian Thrust Belt, southern Norway. Norsk Geologisk Tidsskrift 67, 395–418.Google Scholar
Nystuen, J. P., & Siedlecka, A., 1988. The ‘sparagmites’ of Norway. In Late Proterozoic Stratigraphy of the Northern Atlantic Regions (ed. Winchester, J. A.), pp. 237–52. Glasgow, London: Blackie.CrossRefGoogle Scholar
Page, L. M., 1992. 40Ar/39Ar geochronological constraints on timing of deformation and metamorphism of the Central Norrbotten Caledonides, Sweden. Geological Journal 27, 127–50.CrossRefGoogle Scholar
Pearce, J. A., 1983. The role of sub-continental lithosphere in magma genesis at destructive plate margins. In Continental Basalts and Mantle Xenoliths (eds Hawkesworth, C. J. and Norry, N. J.), pp. 230–49. Nantwich: Shiva.Google Scholar
Pognante, U., 1985. Coronitic reactions and ductile shear zones in the eclogitized ophiolite metagabbro, Western Alps, North Italy. Chemical Geology 108, 93–112.Google Scholar
Robinson, P., 1991. The eye of the petrographer, the mind of the petrologist. Presidental address. American Mineralogist 76, 1781–1810.Google Scholar
Rubie, D. C., 1990. Role of kinetics in formation and preservation of eclogites. In Eclogite fades rocks (ed. Carswell, D. A.), pp. 111–40. Glasgow, London: Blackie.CrossRefGoogle Scholar
Santallier, D., 1988. Mineralogy and crystallization of the Seve eclogites in the Vuoggatjålme area, Swedish Caledonides of Norrbotten. Geologiska Föreningens i Stockholm Förhandlingar 110, 89–98.CrossRefGoogle Scholar
Scotese, C. R., & McKerrow, W. S., 1991. Ordovician plate tectonic reconstructions. Geological Survey of Canada Paper 90 –9, 271–82.Google Scholar
Skjernaa, L., 1989. Tubular folds and sheath folds: definitions and conceptual models for their development, with examples from the Grapesvare area, northern Sweden. Tectonophysics 11, 689–703.Google Scholar
Solyom, Z., Andréasson, P. G., & Johansson, I., 1984. Petrochemistry of Late Proterozoic rift volcanism in Scandinavia II: The Sarv Dolerites (SD) — volcanism in the constructive arm of Iapetus. Lund Publications in Geology 35, 1–42.Google Scholar
Solyom, Z., Gorbatschev, R., & Johansson, I., 1979. The Ottfjället Dolerites. Geochemistry of the dyke swarm in relation to the geodynamics of the Caledonide Orogen of Central Scandinavia. Sveriges Geologiska undersökning, Serie C 756, 1–38.Google Scholar
Solyom, Z., Lindqvist, J.-E., & Johansson, I., 1992. The geochemistry, genesis, and geotectonic setting of Proterozoic dyke swarms in southern and central Sweden. Geologiska Föreningens i Stockholm Förhandlingar 114, 47–65.CrossRefGoogle Scholar
Stephens, M. B., & Gee, D. G., 1985. A tectonic model for the evolution of eugeoclinal terranes in the central Scandinavian Caledonides. In The Caledonide Orogen — Scandinavia and Related Areas (eds Gee, D. G. and Sturt, B. A.), pp. 953–78. Chichester: John Wiley and Sons.Google Scholar
Stephens, M. B., & Van Roermund, H. L. M., 1984. Occurrence of glaucophane and crossite in eclogites of the Seve Nappes, southern Norrbotten Caledonides. Norsk Geologisk Tidsskrift 69, 155–63.Google Scholar
Sturt, B. A., & Roberts, D., 1991. Tectonostratigraphic Relationships and Obduction Histories of Scandinavian Ophiolitic Terranes. In Ophiolite Genesis and the Evolution of the Oceanic Lithosphere (eds Peters, T., Nicolas, A. and Coleman, R. G.), pp. 745–69. Sultanate of Oman: Ministry of Petroleum and Minerals.CrossRefGoogle Scholar
Stølen, L.-K., 1994. The rift-related mafic dyke complex of the Rohkunborri Nappe, Indre Troms, northern Norwegian Caledonides. Norsk Geologisk Tidsskrift 74, 35–47.Google Scholar
Svenningsen, O. M., 1994. The Baltica—Iapetus passive margin dyke complex in the Sarektjåkkå Nappe, northern Swedish Caledonides. Geological Journal 29, 323–54.CrossRefGoogle Scholar
Van Roermund, H. L. M., 1989. High-pressure ultramafic rocks from the Allochthonous Nappes of the Swedish Caledonides. In The Caledonide Geology of Scandinavia (ed. Gayer, R. A.), pp. 205–19. London: Graham and Trotman.CrossRefGoogle Scholar
Vidal, G., & Nystuen, J. P., 1990. Micropaleontology, depositional environment, and biostratigraphy of the Upper Proterozoic Hedmark Group, southern Norway. American Journal of Science 290-A, 170–211.Google Scholar
Wilson, M., 1989. Igneous Petrogenesis. A Global Tectonic Approach. London: Unwin Hyman, 466 pp.CrossRefGoogle Scholar
Winchester, J. A., 1988. Later Proterozoic environments and tectonic evolution in the northern Atlantic lands. In Late Proterozoic Stratigraphy of the Northern Atlantic Regions (ed. Winchester, J. A.), pp. 253–70. Glasgow, London: Blackie.CrossRefGoogle Scholar
Zachrisson, E., & Stephens, M. B., 1984. Mega-structures within the Seve Nappes, southern Norrbotten Caledonides, Sweden (Meeting Proceedings). Meddelanden från Stockholms Universitets Geologiska Institution 255, 241.Google Scholar