View source for Earth:Nena (supercontinent)

{{short description|Early Proterozoic supercontinent}}
 [[File:Columbia supercontinent.png|thumb|Orientation of different continents in Columbia.]]'''Nena''', an acronym for Northern Europe–North America, was the Early Proterozoic amalgamation of Baltica and Laurentia into a single "cratonic landmass", a name first proposed in 1990.<ref name=":0">{{Cite book|url=https://www.worldcat.org/oclc/26097480|title=Mid-Proterozoic Laurentia-Baltica|date=1990|publisher=Geological Association of Canada, Dept. of Earth Sciences|others=Charles F. Gower, Toby Rivers, Arthur Bruce Ryan, Geological Association of Canada|isbn=0-919216-45-5|location=St. John's, Nfld., Canada|oclc=26097480}}</ref> Since then several similar Proterozoic supercontinents have been proposed, including Nuna and Arctica, that include other Archaean cratons, such as [[Earth:Siberia (continent)|Siberia]] and East Antarctica.<ref name=":1">{{Cite journal|last=Meert|first=Joseph G.|date=2012|title=What's in a name? The Columbia (Paleopangaea/Nuna) supercontinent|url=https://linkinghub.elsevier.com/retrieve/pii/S1342937X11003479|journal=Gondwana Research|language=en|volume=21|issue=4|pages=987–993|doi=10.1016/j.gr.2011.12.002}}</ref>
In the original concept Nena formed {{Circa}} {{Ma|1900}} in the Penokean, Makkovikan, Ketilidian, and Svecofennian [[Physics:Orogeny|orogenies]].<ref name=":0" />  However, because Nena excludes several known Archaean cratons, including those in India and Australia, it is strictly speaking not a supercontinent. Although Nena and Nuna share many similarities, Nena accounted for a larger landmass than Nuna. This extended landmass included the Angara, Antarctica, [[Earth:Baltica|Baltica]], [[Earth:Laurentia|Laurentia]], and Siberia bodies.<ref name=":1" /> Nena, or Nuna, can, nevertheless be thought of as the core of [[Earth:Columbia (supercontinent)|Columbia]], another supercontinent concept with several proposed configurations.<ref name=":1" />

The first concept of the Nena supercontinent originated with the southern regions of proto-Laurentia and the western regions proto-Baltica merging throughout the Proterozoic eon.<ref name=":2">{{Cite journal|last=Gower|first=Charles F.|date=1990|title=Stages in the evolution of the southern margin of mid-Proterozoic Laurentia-Baltica|url=http://dx.doi.org/10.1080/11035899209453910|journal=Geologiska Föreningen i Stockholm Förhandlingar|volume=114|issue=4|pages=455–457|doi=10.1080/11035899209453910|issn=0016-786X}}</ref> This concept would eventually be developed to the modern day conceptualization of the Nena supercontinent which includes additions of the Angara, Antarctica, and Siberia landmasses.

Throughout the amalgamation of the microcontinents which would form proto-Nena, several significant geologic processes occurred including orogenesis and continental magmatic accretion. The by-products of these processes can be found numerous regions such as southwest Ontario, northwest British Isles, and Greenland.<ref name=":2" /> These by-products include the Marquette Range supergroup and the Moran Lake and lower Aillik groups northwest of the Makkovik orogen. These geologic findings provided a basis for the concept of the Nena supercontinent. 

Nena as a continent has been associated with the [[Earth:Sudbury Basin|Sudbury Basin Impact]].

==References==
<references />
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== External links ==
* [http://people.earth.yale.edu/sites/default/files/files/Evans/46_11b-Nuna.pdf Referred to as Nuna]

{{Continents of the world}}

{{DEFAULTSORT:Nena (Supercontinent)}}

[[Category:Former supercontinents]]
[[Category:Proterozoic]]



{{Sourceattribution|Nena (supercontinent)}}