Attempted break-up of Rodinia at 850 Ma: geochronological evidence from the Seve-Kalak Superterrane, Scandinavian Caledonides
Lower thrust sheets of the Scandinavian Caledonides derive from the margin of Baltica, which was imbricated during Early Palaeozoic closure of oceans formed during separation of the Baltica, Laurentia and Siberia cratons. At Vistas (Kebnekaise Mts), the Seve Nappe Complex preserves rare lenses of a...
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ftulundlup:oai:lup.lub.lu.se:18aa9a66-8bb1-4e57-b1e0-27469e5f09ef 2023-05-15T18:31:15+02:00 Attempted break-up of Rodinia at 850 Ma: geochronological evidence from the Seve-Kalak Superterrane, Scandinavian Caledonides Paulsson, Oskar Andréasson, Per-Gunnar 2002 https://lup.lub.lu.se/record/324184 eng eng Geological Society of London https://lup.lub.lu.se/record/324184 wos:000179092700012 scopus:84862762756 Journal of the Geological Society; 159(6), pp 751-761 (2002) ISSN: 2041-479X Geology Neoproterozoic Scandinavia Caledonides Rodinia rifting ion probe contributiontojournal/article info:eu-repo/semantics/article text 2002 ftulundlup 2023-02-01T23:32:45Z Lower thrust sheets of the Scandinavian Caledonides derive from the margin of Baltica, which was imbricated during Early Palaeozoic closure of oceans formed during separation of the Baltica, Laurentia and Siberia cratons. At Vistas (Kebnekaise Mts), the Seve Nappe Complex preserves rare lenses of a dolerite-intruded granite formed by anatexis during emplacement of gabbro into metasedimentary rocks. Ion microprobe U-Pb dating of prismatic zircons from the granite yielded an age of 845 +/- 14 Ma (mean square weighed deviation (MSWD) 1.15), interpreted to date magmatic crystallization. Cores of complex crystals indicate protolith ages of 1778 +/- 11 Ma (MSWD 0.86); one core yielded an Archaean age. From narrow rims, a 605 +/- 42 Ma metamorphic age is obtained, and is interpreted to reflect the emplacement of the extensive Vendian rift magmatic dolerite dyke swarm. The age pattern allows correlation with a previously dated magmatic complex within the equivalent Kalak Nappe Complex 300 km to the north. Bimodal magmatic complexes with this age pattern do not occur within the basement of the Caledonide foreland, nor elsewhere within the Baltic Shield. However, recent reinterpretations of the Knoydartian event in Scotland as rift related invites correlation with the West Highland Granite Gneiss, which intruded Moine metasedimentary rocks at c. 870 Ma. In Central Taimyr, 850-900 Ma granites of continental crustal derivation and with 1800-1900 Ma Sm-Nd model age occur associated with c. 740 Ma plagiogranites. Using recent palaeogeographical reconstructions, we interpret the evidence of 850-900 Ma magmatism, in Scandinavia, Scotland and Taimyr as bimodal rift magmatism in connected arms during an attempted break-up of Rodinia. Article in Journal/Newspaper Taimyr Siberia Lund University Publications (LUP) Kalak ENVELOPE(27.055,27.055,70.611,70.611) |
institution |
Open Polar |
collection |
Lund University Publications (LUP) |
op_collection_id |
ftulundlup |
language |
English |
topic |
Geology Neoproterozoic Scandinavia Caledonides Rodinia rifting ion probe |
spellingShingle |
Geology Neoproterozoic Scandinavia Caledonides Rodinia rifting ion probe Paulsson, Oskar Andréasson, Per-Gunnar Attempted break-up of Rodinia at 850 Ma: geochronological evidence from the Seve-Kalak Superterrane, Scandinavian Caledonides |
topic_facet |
Geology Neoproterozoic Scandinavia Caledonides Rodinia rifting ion probe |
description |
Lower thrust sheets of the Scandinavian Caledonides derive from the margin of Baltica, which was imbricated during Early Palaeozoic closure of oceans formed during separation of the Baltica, Laurentia and Siberia cratons. At Vistas (Kebnekaise Mts), the Seve Nappe Complex preserves rare lenses of a dolerite-intruded granite formed by anatexis during emplacement of gabbro into metasedimentary rocks. Ion microprobe U-Pb dating of prismatic zircons from the granite yielded an age of 845 +/- 14 Ma (mean square weighed deviation (MSWD) 1.15), interpreted to date magmatic crystallization. Cores of complex crystals indicate protolith ages of 1778 +/- 11 Ma (MSWD 0.86); one core yielded an Archaean age. From narrow rims, a 605 +/- 42 Ma metamorphic age is obtained, and is interpreted to reflect the emplacement of the extensive Vendian rift magmatic dolerite dyke swarm. The age pattern allows correlation with a previously dated magmatic complex within the equivalent Kalak Nappe Complex 300 km to the north. Bimodal magmatic complexes with this age pattern do not occur within the basement of the Caledonide foreland, nor elsewhere within the Baltic Shield. However, recent reinterpretations of the Knoydartian event in Scotland as rift related invites correlation with the West Highland Granite Gneiss, which intruded Moine metasedimentary rocks at c. 870 Ma. In Central Taimyr, 850-900 Ma granites of continental crustal derivation and with 1800-1900 Ma Sm-Nd model age occur associated with c. 740 Ma plagiogranites. Using recent palaeogeographical reconstructions, we interpret the evidence of 850-900 Ma magmatism, in Scandinavia, Scotland and Taimyr as bimodal rift magmatism in connected arms during an attempted break-up of Rodinia. |
format |
Article in Journal/Newspaper |
author |
Paulsson, Oskar Andréasson, Per-Gunnar |
author_facet |
Paulsson, Oskar Andréasson, Per-Gunnar |
author_sort |
Paulsson, Oskar |
title |
Attempted break-up of Rodinia at 850 Ma: geochronological evidence from the Seve-Kalak Superterrane, Scandinavian Caledonides |
title_short |
Attempted break-up of Rodinia at 850 Ma: geochronological evidence from the Seve-Kalak Superterrane, Scandinavian Caledonides |
title_full |
Attempted break-up of Rodinia at 850 Ma: geochronological evidence from the Seve-Kalak Superterrane, Scandinavian Caledonides |
title_fullStr |
Attempted break-up of Rodinia at 850 Ma: geochronological evidence from the Seve-Kalak Superterrane, Scandinavian Caledonides |
title_full_unstemmed |
Attempted break-up of Rodinia at 850 Ma: geochronological evidence from the Seve-Kalak Superterrane, Scandinavian Caledonides |
title_sort |
attempted break-up of rodinia at 850 ma: geochronological evidence from the seve-kalak superterrane, scandinavian caledonides |
publisher |
Geological Society of London |
publishDate |
2002 |
url |
https://lup.lub.lu.se/record/324184 |
long_lat |
ENVELOPE(27.055,27.055,70.611,70.611) |
geographic |
Kalak |
geographic_facet |
Kalak |
genre |
Taimyr Siberia |
genre_facet |
Taimyr Siberia |
op_source |
Journal of the Geological Society; 159(6), pp 751-761 (2002) ISSN: 2041-479X |
op_relation |
https://lup.lub.lu.se/record/324184 wos:000179092700012 scopus:84862762756 |
_version_ |
1766214981343248384 |