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TitrePaleozoic tectonic and metallogenetic evolution of pericratonic terranes in Yukon, northern British Columbia and eastern Alaska
AuteurNelson, J L; Colpron, M; Piercey, S J; Dusel-Bacon, C; Murphy, D C; Roots, C F
SourcePaleozoic evolution and metallogeny of pericratonic terranes at the Ancient Pacific Margin of North America, Canadian and Alaskan Cordillera; par Colrpon, M (éd.); Nelson, J L (éd.); Geological Association of Canada, Special Paper 45, 2006 p. 323-360; 1 CD-ROM
LiensOnline - En ligne
Séries alt.Secteur des sciences de la Terre, Contribution externe 20060157
ÉditeurAssociation géologique du Canada
Documentpublication en série
Mediapapier; CD-ROM; numérique; en ligne
Formatspdf (Adobe Acrobat Reader); xls (Microsoft Excel)
ProvinceYukon; Colombie-Britannique
SNRC92; 93; 94; 102; 103; 104; 105; 106C; 106D; 106E; 106F; 106L; 114; 115; 116; 117A; 117B; 117C; 117D; 117E; 117F; 117G; 117H
Lat/Long OENS-156.0000 -114.0000 69.0000 49.0000
Sujetsterrains; craton; déformation; roches métamorphiques; roches ignées; roches sédimentaires; failles; plutons; marges continentales; arcs magmatiques; basaltes; rhyolites; gîtes volcanogènes; gisements minéraux; géologie générale; géochimie; géochronologie; minéraux métalliques; sédimentologie; géologie structurale; tectonique; Paléozoïque
Illustrationslocation maps; geological sketch maps; graphs; geochemical plots; bar graphs; cross-sections, structural
ProgrammeProjet de l'ancienne marge du Pacifique du CARTNAT
ProgrammeCRSNG Conseil de recherches en sciences naturelles et en génie du Canada
Résumé(disponible en anglais seulement)
The allochthonous, pericratonic Yukon-Tanana terrane (YTT) underlies much of southwest Yukon, easternmost Alaska
and the Coast and Cassiar mountains of northern B.C. Data obtained through the Ancient Pacific Margin NATMAP
Project (1998-2003) have substantially modified its extent, subdivided it into regional assemblages, and established distinct components of arc and back-arc affinity that define a west-facing Late Devonian to Early Permian arc. Most
of the former YTT in Alaska is now considered parautochthonous.
Some aspects of YTT appear foreign to the continent: intense Devonian-Mississippian arc magmatism, and affiliations
with the younger arc terranes of Quesnellia and Stikinia. A belt of Permian high-pressure rocks, a late Paleozoic marginal
ocean terrane, and Jurassic thrust faults intervene between it and the miogeocline. However, Precambrian detrital
zircon populations, ?Nd values and Pb isotopic ratios from Devonian-Mississippian syngenetic occurrences show
a strong affinity for the northern miogeocline. VHMS mineralization associated with A-type and intraplate volcanism
mark the YTT as a rifting frontal arc to continental back-arc during the Devonian-Mississippian. Simultaneously, the
northwestern continent margin became a broad, extending back-arc region, with normal faulting, coarse clastic
deposition, rift-related volcanism and syngenetic mineralization. Slab rollback drove regional extension, which culminated
in the opening of the Slide Mountain marginal ocean between the YTT arc and North America.
The mid-Permian marked a transition to convergent tectonic style - the closure of the Slide Mountain basin by shortlived
westward subduction under YTT. Within eastern (inboard) YTT, there was a brief phase of arc activity, east-vergent
thrust faulting, exhumation of high P/T rocks and deposition of synorogenic clastic rocks. By the end of the Permian,
YTT and its associated terranes, although still not accreted to their present locations, had once again become part of
the North American margin.