Structural development of migmatites near Skåldö, southwest Finland
The migmatites of the Skåldö area show the effects of an extensive polyphase deformational history at relatively deep crustal levels during the Svecokarelian episode. Despite the complexity of the fold patterns it is possible to establish a deformational sequence into which the many phases of igneou...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
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Geological Society of Finland
1976-12-01
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| Series: | Bulletin of the Geological Society of Finland |
| Online Access: | http://www.geologinenseura.fi/bulletin/Volume48/sgs_bt_048_1_2_pages_043_062.pdf |
| Summary: | The migmatites of the Skåldö area show the effects of an extensive polyphase deformational history at relatively deep crustal levels during the Svecokarelian episode. Despite the complexity of the fold patterns it is possible to establish a deformational sequence into which the many phases of igneous emplacement in the rocks can be placed. There are at least seven successive fold sets and a number of phases of both basic and acidic igneous activity as well as the effects of metamorphism which reached a peak, under amphibolite facies conditions, early in the deformational history. Taken together the various features comprise a complex framework which can be used as a basis for comparison and correlation with the products of the Svecokarelian orogenic episode in other parts of the Baltic Shield. The characteristics of these migmatites in this classic area, viz. their »mixed» aspect as described by J. J. Sederholm, is shown to result from their extensive deformational, metamorphic and igneous history in which tectonic and igneous activity played prominent roles. |
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| ISSN: | 0367-5211 1799-4632 |