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Baltoscandian margin, Sveconorwegian crust lost by subduction during Caledonian collisional orogeny

Gee, David G.; Andréasson, Per Gunnar LU ; Li, Yuan and Krill, Allan (2017) In GFF 139(1). p.36-51
Abstract

Underthrusting of Laurentia by the continental margin of Baltica during Caledonian orogeny resulted in the lateral emplacement of Iapetus Ocean-related terranes of the Upper Allochthon at least 500 km onto Baltica. The underlying Lower and Middle allochthons of the Baltoscandian margin mostly comprise Cryogenian, Ediacaran and Cambro-Silurian sedimentary successions; basement to these formations are present only as minor, isolated fragments, except at the base of the Middle Allochthon and within the underlying windows. The upper parts of the Middle Allochthon are notable for the presence of early Ediacaran dyke-swarms and other components of the Baltoscandian continent–ocean transition zone (COT). New data are presented here on the c.... (More)

Underthrusting of Laurentia by the continental margin of Baltica during Caledonian orogeny resulted in the lateral emplacement of Iapetus Ocean-related terranes of the Upper Allochthon at least 500 km onto Baltica. The underlying Lower and Middle allochthons of the Baltoscandian margin mostly comprise Cryogenian, Ediacaran and Cambro-Silurian sedimentary successions; basement to these formations are present only as minor, isolated fragments, except at the base of the Middle Allochthon and within the underlying windows. The upper parts of the Middle Allochthon are notable for the presence of early Ediacaran dyke-swarms and other components of the Baltoscandian continent–ocean transition zone (COT). New data are presented here on the c. 610 Ma age of the COT-related dolerites in the Kalak Nappe Complex in Northern Norway and also on detrital zircons in the underlying Laksefjord and Gaissa nappes. The former confirms that the Baltoscandian COT has a similar age along the length of the orogen; the latter shows that the detrital zircon signatures in the Lower and Middle allochthons are comparable throughout the orogen. These sedimentary rocks have dominating populations of Mesoproterozoic to latest Palaeoproterozoic zircons similar to those from southern parts of the orogen, where Sveconorwegian complexes comprise the basement to the Caledonides. Thus, they help define the probable character and age of the crystalline basement that existed along this outer margin of Baltica during the Neoproterozoic, continental lower crust that was partly subducted during Ordovician continent-arc collision and subsequently lost beneath Laurentia during the 50 million years of Scandian collisional orogeny.

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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
continent–ocean transition, detrital zircons, Scandinavian Caledonides, subduction systems, Sveconorwegian basement
in
GFF
volume
139
issue
1
pages
16 pages
publisher
Taylor & Francis
external identifiers
  • scopus:84990985867
  • wos:000392852200005
ISSN
1103-5897
DOI
10.1080/11035897.2016.1200667
language
English
LU publication?
yes
id
a44cde3c-68d9-49e3-bf2b-325afe2109fc
date added to LUP
2016-11-01 08:52:13
date last changed
2018-10-07 04:48:16
@article{a44cde3c-68d9-49e3-bf2b-325afe2109fc,
  abstract     = {<p>Underthrusting of Laurentia by the continental margin of Baltica during Caledonian orogeny resulted in the lateral emplacement of Iapetus Ocean-related terranes of the Upper Allochthon at least 500 km onto Baltica. The underlying Lower and Middle allochthons of the Baltoscandian margin mostly comprise Cryogenian, Ediacaran and Cambro-Silurian sedimentary successions; basement to these formations are present only as minor, isolated fragments, except at the base of the Middle Allochthon and within the underlying windows. The upper parts of the Middle Allochthon are notable for the presence of early Ediacaran dyke-swarms and other components of the Baltoscandian continent–ocean transition zone (COT). New data are presented here on the c. 610 Ma age of the COT-related dolerites in the Kalak Nappe Complex in Northern Norway and also on detrital zircons in the underlying Laksefjord and Gaissa nappes. The former confirms that the Baltoscandian COT has a similar age along the length of the orogen; the latter shows that the detrital zircon signatures in the Lower and Middle allochthons are comparable throughout the orogen. These sedimentary rocks have dominating populations of Mesoproterozoic to latest Palaeoproterozoic zircons similar to those from southern parts of the orogen, where Sveconorwegian complexes comprise the basement to the Caledonides. Thus, they help define the probable character and age of the crystalline basement that existed along this outer margin of Baltica during the Neoproterozoic, continental lower crust that was partly subducted during Ordovician continent-arc collision and subsequently lost beneath Laurentia during the 50 million years of Scandian collisional orogeny.</p>},
  author       = {Gee, David G. and Andréasson, Per Gunnar and Li, Yuan and Krill, Allan},
  issn         = {1103-5897},
  keyword      = {continent–ocean transition,detrital zircons,Scandinavian Caledonides,subduction systems,Sveconorwegian basement},
  language     = {eng},
  number       = {1},
  pages        = {36--51},
  publisher    = {Taylor & Francis},
  series       = {GFF},
  title        = {Baltoscandian margin, Sveconorwegian crust lost by subduction during Caledonian collisional orogeny},
  url          = {http://dx.doi.org/10.1080/11035897.2016.1200667},
  volume       = {139},
  year         = {2017},
}