Geophysical and geological modelling of the Sotkuma gneiss dome; Implications for the relationships of the Archean basement and the Paleoproterozoic cover in North Karelia, Eastern Finland
We studied the basement-cover relations in North Karelia, eastern Finland by modelling (1) regionally the thickness of the cover sequence and (2) the geometry of the Sotkuma dome (basement inlier). We utilized geological and aeromagnetic maps, together with the abundant structural data, in compilati...
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Geological Society of Finland
2019
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Online Access: | https://doi.org/10.17741/bgsf/91.2.003 https://doaj.org/article/6e206b507f2a437a8b58c555f47fb3f4 |
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ftdoajarticles:oai:doaj.org/article:6e206b507f2a437a8b58c555f47fb3f4 2023-05-15T17:00:10+02:00 Geophysical and geological modelling of the Sotkuma gneiss dome; Implications for the relationships of the Archean basement and the Paleoproterozoic cover in North Karelia, Eastern Finland Jarmo Kohonen Seppo Elo Markku Paananen 2019-12-01T00:00:00Z https://doi.org/10.17741/bgsf/91.2.003 https://doaj.org/article/6e206b507f2a437a8b58c555f47fb3f4 EN eng Geological Society of Finland https://www.geologinenseura.fi/sites/geologinenseura.fi/files/bulletin_vol91_2_199-219_2019_kohonen-etal.pdf https://doaj.org/toc/0367-5211 https://doaj.org/toc/1799-4632 doi:10.17741/bgsf/91.2.003 0367-5211 1799-4632 https://doaj.org/article/6e206b507f2a437a8b58c555f47fb3f4 Bulletin of the Geological Society of Finland, Vol 91, Iss 2, Pp 199-219 (2019) basement inlier basement-cover relationships gravimetric modelling gneiss dome sotkuma north karelia finland Geology QE1-996.5 article 2019 ftdoajarticles https://doi.org/10.17741/bgsf/91.2.003 2022-12-31T13:37:27Z We studied the basement-cover relations in North Karelia, eastern Finland by modelling (1) regionally the thickness of the cover sequence and (2) the geometry of the Sotkuma dome (basement inlier). We utilized geological and aeromagnetic maps, together with the abundant structural data, in compilation of the cross-sections. The sections were adjusted by gravimetric modelling of the regional data and detailed profiles around the Sotkuma dome. A schematic 3D block-model visualizing regionally the depth and overall geometry of the basement-cover interface in North Karelia is presented. Both the Archean basement complex and the Paleoproterozoic cover sequence display structures developed in response to collisional tectonic processes c. 1.92–1.82 Ga ago. Compared to the thickness of the Archean crust, the sedimentary cover sequence in North Karelia is rather thin; the modelling along the regional gravity profile indicates overall cover thicknesses around 4 to 6 km. Between the Sotkuma and Kontiolahti domes the cover rocks of the Höytiäinen Belt form an almost upright outlier between the basement blocks. Within the Outokumpu Area the basement-cover interface is interpreted as a very open synformal structure between the Sotkuma dome and the Maarianvaara basement inlier. According to the detailed gravity profile modelling around the Sotkuma dome, the basement-cover interface dips steeply (in the north and west) or moderately (in the south) outwards. The eastern margin of the dome is modelled as a step-like structure of west dipping thrust slices of basement gneiss. The modelled geometry, the structural features and the pattern of mafic dykes within the dome, are interpreted with a multistage genesis: (1) repeated rifting and normal faulting (N-margin ~2.2 Ga; E-margin ~2.1 Ga) during the extensional basin formation stage, and (2) crustal shortening (~1.9 Ga) and associated thrusting. In our modelling the Sotkuma basement window represents the northernmost part of a large ‘basement high’ block, spatially extending some ... Article in Journal/Newspaper karelia* Directory of Open Access Journals: DOAJ Articles Dome The ENVELOPE(166.000,166.000,-85.367,-85.367) Bulletin of the Geological Society of Finland 91 2 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
basement inlier basement-cover relationships gravimetric modelling gneiss dome sotkuma north karelia finland Geology QE1-996.5 |
spellingShingle |
basement inlier basement-cover relationships gravimetric modelling gneiss dome sotkuma north karelia finland Geology QE1-996.5 Jarmo Kohonen Seppo Elo Markku Paananen Geophysical and geological modelling of the Sotkuma gneiss dome; Implications for the relationships of the Archean basement and the Paleoproterozoic cover in North Karelia, Eastern Finland |
topic_facet |
basement inlier basement-cover relationships gravimetric modelling gneiss dome sotkuma north karelia finland Geology QE1-996.5 |
description |
We studied the basement-cover relations in North Karelia, eastern Finland by modelling (1) regionally the thickness of the cover sequence and (2) the geometry of the Sotkuma dome (basement inlier). We utilized geological and aeromagnetic maps, together with the abundant structural data, in compilation of the cross-sections. The sections were adjusted by gravimetric modelling of the regional data and detailed profiles around the Sotkuma dome. A schematic 3D block-model visualizing regionally the depth and overall geometry of the basement-cover interface in North Karelia is presented. Both the Archean basement complex and the Paleoproterozoic cover sequence display structures developed in response to collisional tectonic processes c. 1.92–1.82 Ga ago. Compared to the thickness of the Archean crust, the sedimentary cover sequence in North Karelia is rather thin; the modelling along the regional gravity profile indicates overall cover thicknesses around 4 to 6 km. Between the Sotkuma and Kontiolahti domes the cover rocks of the Höytiäinen Belt form an almost upright outlier between the basement blocks. Within the Outokumpu Area the basement-cover interface is interpreted as a very open synformal structure between the Sotkuma dome and the Maarianvaara basement inlier. According to the detailed gravity profile modelling around the Sotkuma dome, the basement-cover interface dips steeply (in the north and west) or moderately (in the south) outwards. The eastern margin of the dome is modelled as a step-like structure of west dipping thrust slices of basement gneiss. The modelled geometry, the structural features and the pattern of mafic dykes within the dome, are interpreted with a multistage genesis: (1) repeated rifting and normal faulting (N-margin ~2.2 Ga; E-margin ~2.1 Ga) during the extensional basin formation stage, and (2) crustal shortening (~1.9 Ga) and associated thrusting. In our modelling the Sotkuma basement window represents the northernmost part of a large ‘basement high’ block, spatially extending some ... |
format |
Article in Journal/Newspaper |
author |
Jarmo Kohonen Seppo Elo Markku Paananen |
author_facet |
Jarmo Kohonen Seppo Elo Markku Paananen |
author_sort |
Jarmo Kohonen |
title |
Geophysical and geological modelling of the Sotkuma gneiss dome; Implications for the relationships of the Archean basement and the Paleoproterozoic cover in North Karelia, Eastern Finland |
title_short |
Geophysical and geological modelling of the Sotkuma gneiss dome; Implications for the relationships of the Archean basement and the Paleoproterozoic cover in North Karelia, Eastern Finland |
title_full |
Geophysical and geological modelling of the Sotkuma gneiss dome; Implications for the relationships of the Archean basement and the Paleoproterozoic cover in North Karelia, Eastern Finland |
title_fullStr |
Geophysical and geological modelling of the Sotkuma gneiss dome; Implications for the relationships of the Archean basement and the Paleoproterozoic cover in North Karelia, Eastern Finland |
title_full_unstemmed |
Geophysical and geological modelling of the Sotkuma gneiss dome; Implications for the relationships of the Archean basement and the Paleoproterozoic cover in North Karelia, Eastern Finland |
title_sort |
geophysical and geological modelling of the sotkuma gneiss dome; implications for the relationships of the archean basement and the paleoproterozoic cover in north karelia, eastern finland |
publisher |
Geological Society of Finland |
publishDate |
2019 |
url |
https://doi.org/10.17741/bgsf/91.2.003 https://doaj.org/article/6e206b507f2a437a8b58c555f47fb3f4 |
long_lat |
ENVELOPE(166.000,166.000,-85.367,-85.367) |
geographic |
Dome The |
geographic_facet |
Dome The |
genre |
karelia* |
genre_facet |
karelia* |
op_source |
Bulletin of the Geological Society of Finland, Vol 91, Iss 2, Pp 199-219 (2019) |
op_relation |
https://www.geologinenseura.fi/sites/geologinenseura.fi/files/bulletin_vol91_2_199-219_2019_kohonen-etal.pdf https://doaj.org/toc/0367-5211 https://doaj.org/toc/1799-4632 doi:10.17741/bgsf/91.2.003 0367-5211 1799-4632 https://doaj.org/article/6e206b507f2a437a8b58c555f47fb3f4 |
op_doi |
https://doi.org/10.17741/bgsf/91.2.003 |
container_title |
Bulletin of the Geological Society of Finland |
container_volume |
91 |
container_issue |
2 |
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1766052791691771904 |