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TitleReprint of "Key paleomagnetic poles and their use in Proterozoic continent and supercontinent reconstructions: A review"
AuthorBuchan, K L
SourcePrecambrian Research vol. 244, 2014 p. 5-22,
Alt SeriesEarth Sciences Sector, Contribution Series 20130003
PublisherElsevier BV
Mediapaper; on-line; digital
File formatpdf
ProvinceBritish Columbia; Alberta; Saskatchewan; Manitoba; Ontario; Quebec; New Brunswick; Nova Scotia; Prince Edward Island; Newfoundland and Labrador; Northwest Territories; Yukon; Nunavut; Canada
NTS1; 2; 3; 10; 11; 12; 13; 14; 15; 16; 20; 21; 22; 23; 24; 25; 26; 27; 28; 29; 30; 31; 32; 33; 34; 35; 36; 37; 38; 39; 40; 41; 42; 43; 44; 45; 46; 47; 48; 49; 52; 53; 54; 55; 56; 57; 58; 59; 62; 63; 64; 65; 66; 67; 68; 69; 72; 73; 74; 75; 76; 77; 78; 79; 82; 83; 84; 85; 86; 87; 88; 89; 92; 93; 94; 95; 96; 97; 98; 99; 102; 103; 104; 105; 106; 107; 114O; 114P; 115; 116; 117; 120; 340; 560
Lat/Long WENS-180.0000 180.0000 90.0000 -90.0000
Subjectstectonics; paleomagnetic poles; paleomagnetism; paleomagnetic interpretations; continental drift; polar wandering; Precambrian; Proterozoic
Illustrationstables; location maps
ProgramGEM: Geo-mapping for Energy and Minerals Geomapping for Energy and Minerals (GEM) - Minerals Component
AbstractKey paleomagnetic poles are poles that are well defined and precisely dated. The rock unit from which thepole is derived must have a precise (usually U-Pb) age and the pole itself must be demonstrated primarywith a rigorous field test. The use of key poles is essential in defining reliable apparent polar wanderpaths (APWPs) and establishing continental reconstructions. Many hundreds of Proterozoic paleopoleshave been published from around the globe, but only ?45 are from large craton interiors and pass thekey pole criteria. Most key poles are from mafic dykes and sills in the Superior craton (pre-1.83 Ga)or Laurentia (post-1.80 Ga) or Baltica. As a result, with occasional exceptions, it is difficult to defineor compare reliable APWP segments in order to test Proterozoic continental reconstructions. However,there are now sufficient age matches or approximate age matches for pairs of key poles from a number ofcratons to help constrain their relative locations. In this analysis, Proterozoic key poles are identified andtheir use in constructing APWPs and testing continent and supercontinent reconstructions is discussed.This key pole database establishes a well constrained Superior craton-Laurentia APWP for much of theProterozoic that can be used as a reference track against which a growing number of individual keypoles from other cratons can be compared. There is now a robust Baltica-Laurentia reconstruction for?330 m.y. between 1.59 and 1.26 Ga using this approach and potentially for ?570 m.y. between 1.83 and1.26 Ga if additional key and non-key poles from well-dated units are considered. Key pole comparisonsfor several other cratons yield preliminary constraints on the relative movement of cratons (e.g., Slaveand Superior cratons in the Paleoproterozoic) or on specific elements of continental reconstructions (e.g.,Amazonia and Baltica in the Mesoproterozoic, South China craton and Australia in the Neoproterozoic,or Baltica and Laurentia also in the Neoproterozoic).
Summary(Plain Language Summary, not published)
Paleomagnetism "the study of Earth's ancient magnetic field as recorded in volcanic or sedimentary rocks" is a powerful technique for determining the past location of continents. Precisely-dated ¿key¿ paleopoles define the position (latitude and orientation) of a continent relative to the earth's rotation axis at the time of rock formation. If key paleopoles of the same age are determined for two or more continents, the continents¿ ancient positions can be compared. The global database of key paleopoles is catalogued and used to analyse continental reconstructions during the Proterozoic. The data establish a reconstruction of Laurentia (ancestral North America and Greenland) and Baltica (ancestral Scandinavia and eastern Russia) with northern Norway and the Kola Peninsula of Russia adjacent to northeastern Greenland. Other more tentative reconstructions are also examined including Amazonia (northern South America), Baltica and Laurentia, and South China and Australia.

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