| Titre | Pre-Mid Mesozoic tectonic evolution of the Yukon-Tanana Terrane, Yukon and Alaska |
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| Auteur | Mortensen, J K |
| Source | Tectonics vol. 11, no. 4, 1992 p. 836-853, https://doi.org/10.1029/91tc01169 |
| Image |  |
| Année | 1992 |
| Séries alt. | Commission géologique du Canada, Contributions aux publications extérieures 15890 |
| Éditeur | Wiley-Blackwell |
| Document | publication en série |
| Lang. | anglais |
| DOI | https://doi.org/10.1029/91tc01169 |
| Media | papier; en ligne; numérique |
| Formats | pdf |
| Province | Yukon |
| Région | Alaska |
| Lat/Long OENS | -160.0000 -128.0000 65.0000 60.0000 |
| Sujets | évolution tectonique; antécédents tectoniques; magmatisme; arcs magmatiques; géologie du socle; Terrane de Cassiar ; Terrane de Yukon-Tanana; géologie générale; tectonique; Mésozoïque; Dévonien; Permien;
Trias |
| Illustrations | cartes de localisation; coupes lithologiques |
| Diffusé | 2010 07 26 |
| Résumé | (disponible en anglais seulement)
Yukon-Tanana Terrane (YTT) underlies much of central and western Yukon and east central Alaska. Its history and tectonic evolution, particularly prior to
mid-Mesozoic time, has been largely obscured by younger magmatism and tectonism. The application of geochronological and isotopic techniques over the past decade, together with detailed field studies in certain critical areas of the terrane, has shed
new light on the early history of YTT. Much of YTT is a product of episodic continental arc magmatism, with three main pulses in Late Devonian-Early Mississippian, mid-Permian, and Late Triassic-Early Jurassic time. From Late Devonian to
mid-Mississippian time, subduction was north or northeast dipping, but arc polarity was apparently reversed by mid-Permian time. The main, subhorizontal structural fabric characterizing much of YTT was produced between mid-Permian time and the onset
of renewed magmatism in Late Triassic time and probably reflects a major continent-continent collision. Although the Triassic-Jurassic magmatism is also considered to be arc related, it occurred over a very broad area of not only YTT, but also
Quesnellia, and the Stikine, Nisling, Cache Creek, and Slide Mountain terranes. This magmatism appears to have coincided with final amalgamation of the Intermontane Superterrane, and the arc polarity and the position and orientation of the associated
subduction zone is still controversial. Available evidence suggests that Nisling Terrane is closely related to YTT and mainly consists of older strata that underlie the Devonian and younger units generally considered to be more typical of YTT. There
are close similarities between YTT and a number of other "pericratonic" terranes in the central and eastern parts of the Cordillera, and it is likely that these terranes originally formed a single arc and arc basement assemblage which has now been
fragmented and dispersed by transcurrent faulting. |
| GEOSCAN ID | 203776 |
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