| Title | Paleozoic tectonic and metallogenetic evolution of pericratonic terranes in Yukon, northern British Columbia and eastern Alaska |
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| Author | Nelson, J L; Colpron, M; Piercey, S J; Dusel-Bacon, C; Murphy, D C; Roots, C F |
| Source | Paleozoic evolution and metallogeny of pericratonic terranes at the Ancient Pacific Margin of North America, Canadian and Alaskan Cordillera; by Colrpon, M (ed.); Nelson, J L (ed.); Geological Association
of Canada, Special Paper 45, 2006 p. 323-360; 1 CD-ROM  Open Access |
| Links | Online - En ligne
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| Image |  |
| Year | 2006 |
| Alt Series | Earth Sciences Sector, Contribution Series 20060157 |
| Publisher | Geological Association of Canada |
| Document | serial |
| Lang. | English |
| Media | paper; CD-ROM; digital; on-line |
| File format | pdf (Adobe Acrobat Reader); xls (Microsoft Excel) |
| Province | Yukon; British Columbia |
| NTS | 92; 93; 94; 102; 103; 104; 105; 106C; 106D; 106E; 106F; 106L; 114; 115; 116; 117A; 117B; 117C; 117D; 117E; 117F; 117G; 117H |
| Area | Alaska; Canada; United States of America |
| Lat/Long WENS | -156.0000 -114.0000 69.0000 49.0000 |
| Subjects | general geology; geochemistry; geochronology; metallic minerals; sedimentology; structural geology; tectonics; terranes; craton; deformation; metamorphic rocks; igneous rocks; sedimentary rocks; faults;
plutons; continental margins; magmatic arcs; basalts; rhyolites; volcanogenic deposits; mineral deposits; Paleozoic |
| Illustrations | location maps; geological sketch maps; graphs; geochemical plots; bar graphs; cross-sections, structural |
| Program | Ancient Pacific Margin NATMAP Project |
| Program | NSERC Natural Sciences and Engineering Research Council of
Canada |
| Released | 2006 01 01 |
| Abstract | 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. |
| GEOSCAN ID | 222611 |
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