Some key issues in reconstructions of Proterozoic supercontinents

Supercontinents containing most of the earth's continental crust are considered to have existed at least twice in Proterozoic time. The younger one, Rodinia, formed at ∼1.0 Ga by accretion and collision of fragments produced by breakup of the older supercontinent, Columbia, which was assembled...

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Bibliographic Details
Published in:Journal of Asian Earth Sciences
Main Author: Luk, JMC
Format: Conference Object
Language:English
Published: Pergamon. The Journal's web site is located at http://www.elsevier.com/locate/jseaes 2006
Subjects:
Online Access:https://doi.org/10.1016/j.jseaes.2004.06.010
http://library.hku.hk:4550/resserv?sid=HKU:IR&issn=1367-9120&volume=28&issue=1&spage=3&epage=19&date=15&atitle=Some+key+issues+in+reconstructions+of+Proterozoic+supercontinents
http://hdl.handle.net/10722/72629
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Summary:Supercontinents containing most of the earth's continental crust are considered to have existed at least twice in Proterozoic time. The younger one, Rodinia, formed at ∼1.0 Ga by accretion and collision of fragments produced by breakup of the older supercontinent, Columbia, which was assembled by global-scale 2.0-1.8 Ga collisional events. Little consensus has been reached regarding configurations of these supercontinents because of some unresolved issues concerning continental fits. One of these issues concerns how Siberia was related to Laurentia. Previous reconstructions that consider the Aldan Shield of Siberia as a continuation of the Wyoming Province of Laurentia have been largely abandoned in favor of models connecting Siberia to northern Laurentia, but it remains controversial which part of Siberia is contiguous with northern Laurentia. Also at issue is the western Laurentia-Australia-East Antarctica connection. Most Rodinia reconstructions place Australia, together with East Antarctica, adjacent to either western Canada (the SWEAT hypothesis) or the western United States (the AUSWUS hypothesis). However, recent studies combining paleomagnetic and isotopic age data have called into question the validity of SWEAT, AUSWUS and other variants. Another issue is the position of North China in Rodinia/Columbia. Limited paleomagnetic data seem to be consistent with the Paleo-Mesoproterozoic North China-Siberia/Baltica connection, whereas geological data support the recently proposed Archean to Mesoproterozoic North China-India connection. Controversial issues have also been raised about the timing and history of the amalgamation and fragmentation of South America and West Africa. Both geological and paleomagnetic data suggest that South America (São Francisco and Amazonia Cratons) and West Africa (Congo and West African Cratons) coalesced into a single landmass along the 2.1-2.0 Ga Transamazonian/Eburnean orogens. However, whether they were divorced and then re-married to form part of Gondwana, or remained ...