Early Proterozoic nappe formation: an example from Sodankylä, Finland, Northern Baltic Shield
The Central Lapland Greenstone belt comprises rift-related metavolcanic and metasedimentary rocks representing one of the largest supracrustal belts in the Baltic Shield. The Sodankylä area in the central part of the belt represents a complex thrust duplex within a nappe overlying Belomorian Archaea...
| Published in: | Geological Magazine |
|---|---|
| Main Authors: | , |
| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
Cambridge University Press (CUP)
2002
|
| Subjects: | |
| Online Access: | http://dx.doi.org/10.1017/s0016756801006094 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0016756801006094 |
| Summary: | The Central Lapland Greenstone belt comprises rift-related metavolcanic and metasedimentary rocks representing one of the largest supracrustal belts in the Baltic Shield. The Sodankylä area in the central part of the belt represents a complex thrust duplex within a nappe overlying Belomorian Archaean basement and autocthonous Luirojoki calc-silicate rocks. Here, an early D 1 schistosity is axial planar to at least three coaxial generations of southward-verging, subhorizontal, E–W-plunging D 1 folds associated with major southwards thrusting. D 2 is represented by broad, map-scale, upright, NE-trending folds in the south and crenulations in the north. Staurolite-grade metamorphism represented by post-tectonic andalusite + staurolite + kyanite assemblages occurred after D 2 folding. Later D 3 deformation was limited to local NW-trending folds and sinistral faults. The internal nappe-like structure of the Central Lapland Greenstone belt suggests that it represents the foreland of a large collisional complex cored by the Lapland Granulite belt. |
|---|