Hostname: page-component-78c5997874-v9fdk Total loading time: 0 Render date: 2024-11-11T09:45:38.942Z Has data issue: false hasContentIssue false
  • English
  • Français

Structural evolution of Svecokarelian migmatites, southern Finland: a study of Proterozoic crustal development

Published online by Cambridge University Press:  03 November 2011

A. M. Hopgood
A. M. Hopgood
Affiliation:
Department of Geology, University of St Andrews, St Andrews, Fife KY16 9ST, Scotland.
Get access Rights & Permissions [Opens in a new window]

Abstract

Svecokarelian migmatites in the Jussarö area of the southern Finnish archipelago comprise tonalitic gneiss, amphibolite, metagabbro, microgranite, the metamorphosed derivatives of sediments, including carbonates and graded argillites, together with later-emplaced potassic granite, and basic and acidic pegmatites. The rock assemblage shows evidence of repeated deformation; a succession of 15 sets of folds (and fold-related structures) is identified and documented. There are two sets of early intraf oliai isoclinal folds (Faa and Fab), isoclinal folds (Fbr), recumbent folds (Fx), upright open folds (Fy), tight upright folds (Fbb), two sets of asymmetrical folds (Fc and Fd), ‘scar’ folds (Fb1, Fcb Fd1), slip folds Fb, conjugate shear folds (Fe), angular folds (Fn), open warps (Fw) and tight ductile shears (Fds). From isotopie evidence reported elsewhere, the evolution of this crustal segment of the Svecokarelides is known to have spread over a period of approximately 200 m.y. from c. 1900 m.y. to c. 1700 m.y.

Keywords

amphibolitegranitemetagabbrometasedimentneosomepegmatitepolyphase deformationsubduction
Type
Research Article
Information
Earth and Environmental Science Transactions of The Royal Society of Edinburgh , Volume 74 , Issue 4 , 1984 , pp. 229 - 264
Copyright
Copyright © Royal Society of Edinburgh 1984

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

Bayly, B. M., Borradaile, G. J. & Powell, C. M. (eds). 1977. Atlas of rock cleavage (Provisional edition) Hobart: University of Tasmania.Google Scholar
Berthelsen, A., Bondersen, E. & Jensen, S. B. 1962. On the so-called wild migmatites. KRYSTALINIKUM 1, 31–49.Google Scholar
Donath, F. A. & Parker, R. B. 1964. Folds and folding. BULL GEOL SOC AM 75, 45–62.CrossRefGoogle Scholar
Fleuty, M. J. 1964. The description of folds. PROC GEOL ASSOC 75, 461–92.CrossRefGoogle Scholar
Hobbs, B. E., Means, W. D. & Williams, P. F. 1976. An outline of structural geology. New York: Wiley.Google Scholar
Hopgood, A. M. 1971. Correlation by tectonic sequence in Precambrian gneiss terrains. SPEC PUBL GEOL SOC AUST 3, 367–76.Google Scholar
Hopgood, A. M. 1973. Significance of deformational sequence in discriminating between Precambrian terrains. In Lister, L. A. (ed.) Symposium on granites, gneisses and related rocks, 45–51. SPEC PUBL GEOL SOC S AFR 3.Google Scholar
Hopgood, A. M. 1980. Polyphase fold analysis of gneisses and migmatites. TRANS R SOC EDINBURGH EARTH SCI 71, 55–68.CrossRefGoogle Scholar
Hopgood, A. M. & Bowes, D. R. 1972. Application of structural sequence to the correlation of Precambrian gneisses, Outer Hebrides, Scotland. BULL GEOL SOC AM 83, 107–28.Google Scholar
Hopgood, A. M. & Bowes, D. R. 1978. Neosomes of polyphase agmatites as time-markers in complexly deformed migmatites. GEOL RUNDSCH 67, 313–30.CrossRefGoogle Scholar
Hopgood, A. M., Bowes, D. R. & Addison, J. 1976. Structural development of migmatites near Skåldö, southwest Finland. BULL GEOL SOC FINL 48, 43–62.Google Scholar
Hopgood, A. M., Bowes, D. R., Kouvo, O. & Halliday, A. N. 1983. U–Pb and Rb–Sr isotopie study of polyphase deformed migmatites in the Svecokarelides, southern Finland. In Atherton, M. P. and Gribble, C. D. (eds). Migmatites, melting and metamorphism, 80–92. Nantwich: Shiva.Google Scholar
Härme, M. 1960. [Map of Pre-Quaternary rocks] B. I. Turku. The General Geological Map of Finland, 1:400,000.Google Scholar
Härme, M. 1965. On the potassium migmatites of southern Finland. BULL COMM GEOL FINL 219.Google Scholar
Lattala, M. 1973. [Map of Pre-Quaternary rocks] 2013 Jussarö. Geological Map of Finland, 1:100,000.Google Scholar
Ramsay, J. G. 1967. Folding and fracturing of rocks, New York: McGraw Hill.Google Scholar
Sander, B. 1970. An Introduction to the Study of Fabrics of Geological Bodies (translated by Phillips, F. C. & Windsor, G.). New York: Pergamon.Google Scholar
Sederholm, J. J. 1907. On granites and gneiss, their origins, relations and occurrence in the Precambrian complex of Fenno-Scandia. BULL COMM GEOL FINL 23.Google Scholar
Sederholm, J. J. 1967. Selected works: granites and migmatites. Edinburgh: Oliver & Boyd.Google Scholar
Turner, F. J. and Weiss, L. E. 1963. Structural analysis of metamorphic tectonites. New York: McGraw-Hill.Google Scholar