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TitreLower Paleozoic rocks around today's Arctic Ocean: two ancestral continents and associated plates; Alaskan rotation unnecessary and unlikely
AuteurCecile, M P; Lane, L S; Khudoley, A K; Kos'ko, M K
SourceICAM III: Third International Conference on Arctic Margins (ICAM III), volume, II; par Tessensohn, F (éd.); Roland, N W (éd.); Polarforschung vol. 69, (1999), 2001 p. 235-241
LiensOnline - En ligne
Séries alt.Commission géologique du Canada, Contributions aux publications extérieures 1998006
ÉditeurCommission géologique du Canada
RéunionICAM III: Third International Conference on Arctic Margins; Celle; DE; Octobre 12-16, 1998
Documentpublication en série
ProvinceRégion extracotière du nord
SNRC120; 340; 560; 107; 117; 106; 96; 97; 87; 77; 28; 38; 48; 58; 68; 98; 88; 78; 19; 29; 39; 49; 59; 69; 99; 89; 79
Lat/Long OENS 113.2500 -128.0000 90.0000 63.0000
Sujetsmarges continentales; croûte océanique; bassins; carbonates; géologie de l'arctique; chailles; schistes; paléogéographie; antécédents tectoniques; décrochement horizontal; tectonique; Paléozoïque; Dévonien
Illustrationslocation maps; geological sketch maps
ProgrammeL'Accord Canada-Russie sur la coopération dans l'Arctique et le Nord
Résumé(disponible en anglais seulement)
Much of the present day Lower Paleozoic strata around the Arctic Ocean can be tied either to the ancestral Laurentian continent 01' to the ancestral Siberian continent. Correlated with Laurentia (Arctic Laurentian Assemblage) are the Canadian Arctic Islands, northern Alaska and northern Chukotka, including Wrangel Island. Correlated with ancestral Siberia (Arctic Siberian Assemblage) are the Verkhoyansk and Taimyr fold belts on the north and east of the Siberian Plateau, Omolon microcontinent bordered by the KoIyma fold belt on the west, the New Siberian Islands and Omulevka blocks. The New Siberian Islands and elongate Omulevka block appear to have been pieces of Siberia rifted away during the Middle Devonian. The Omolon microcontinent has also been postulated to have rifted away from Siberia during the Devonian but the existence of the Kolyma fold-belt with Phanerozoic and Proterozoic supracrustal strata facing Siberia suggests an older time of separation.
Both the Arctic Laurentian and Arctic Siberian assemblages had miogeoclines that opened into ancestral ocean basins towards the modern day Arctic Ocean. Within the Arctic Laurentian Assemblage the Canadian Arctic Islands joined to Alaska-Chukotka at an obtuse angle aeross a Paleozoie aulaeogen (Riehardson Trough). In the aulacogen is a thick succession of earbonate-dominated Lower Paleozoic basin facies, while to the northwest on the eastern Arctie Alaskan Plate, equivalent strata are very thin chert and shale miogeoclinal basin facies. The present day angular relationships, are similar to those expected for a triple-rift system with an ocean basin on the north formed from a rift approximately paralleling the modern ocean margin of the Canadian Arctic Islands, and a seeond rift paralleling the modern coast of northern Alaska-Chukotka. The aulaeogen would have been a failed rift. This indicates that there
was an ancestral ocean in the position of Canada Basin in the Lower Paleozoie. This paleogeography differs from the popular rotationist plate reeonstruction that shows Alaska and Chukotka against the Canadian Aretic Islands in the Paleozoic. In this scenario a narrow trough or ocean would have had to extend from the Richardson Trough north between pre-rotation Alaska and the Canadian Arctic Islands. The present day facies pattern suggests a northward transition from trough to open miogeocline rather than a continuous trough or closed ocean.