| Titre | Reconsideration of Cenozoic drainage evolution in southern Yukon, Canada through digital terrain model restoration of the Tintina Fault |
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| Auteur | Ryan, J J; Hayward, N ; Jackson, L E |
| Source | Margins through time : GAC-MAC 2016; Association géologique du Canada-Association minéralogique du Canada, Réunion annuelle, Programme et résumés vol. 39, 2016 p. 82  Accès ouvert |
| Liens | Online - En ligne (complete volume - volume
complet, PDF, 1.3 MB)
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| Image |  |
| Année | 2016 |
| Séries alt. | Ressources naturelles Canada, Contribution externe 20190369 |
| Éditeur | Association géologique du Canada |
| Réunion | GAC-MAC 2016; Whitehorse, YK; CA; juin 1-3, 2016 |
| Document | publication en série |
| Lang. | anglais |
| Media | en ligne; numérique |
| Formats | pdf |
| Province | Yukon |
| Région | Fleuve Yukon; Yukon Plateau |
| Sujets | paléodrainage; modélisation numérique de terrain; Faille de Tintina ; géologie structurale; Sciences et technologie; Nature et environnement; Phanérozoïque; Cénozoïque |
| Programme | GEM2 : La géocartographie de l'énergie et des minéraux Redéfinition des blocs de la croûte terrestre de l'ouest de la Cordillère |
| Diffusé | 2016 06 01 |
| Résumé | (disponible en anglais seulement)
The northerly directed Yukon River basin, which captures drainage from across the Yukon Plateau, is characterized by reaches that are offset along the large
strike length Tintina fault (TF). The drainages also feature cross-cutting valley systems with underfit streams or contemporary stream flow directions that are opposite from what would be expected from paleoflow indicators, such as descent directions
interpreted from fluvial terrace deposits. Previous interpretations of the regions drainage history postulated rather convincingly that Miocene or older southward drainage of the paleo-Yukon River predominated prior to the onset of regional
glaciation at ca. 2.6 Ma, wherein glacial damming was to have diverted much of the southerly drainage towards the northwest into the Bering Sea via the ancestral Kwikhpak River basin in Alaska. We explore the impact on regional drainage development
imposed by the ~430 km of right lateral transcurrent movement along the TF much earlier in the Cenozoic Era. While the Yukon Plateau is generally considered by many researchers to be a relatively young (e.g. Miocene) physiographic feature, the
regionally widespread preservation of middle Cretaceous to Paleocene lithological successions demonstrate relatively low incision rates over the last 100 million years and indicate that it has been a stable feature since the late Mesozoic. We
re-evaluate and reconstruct the Cenozoic drainage resulting from progressive displacement of digital terrain model data along the TF. Major physiographic elements (uplands and major valleys) were restored and the drainage modeled at specific TF
offsets, wherein drainage was episodically diverted by the alignment of previously unconnected valleys. The models show the drainage of the Yukon River northwestward into Alaska via Yukon Flats has only been possible at TF displacements from 0 to
about 50-55 km. The models suggest that at an offset of greater than approximately 55 km, an alignment of highlands precluded flow to the northwest, and drainage of the Yukon Plateau was southerly via the White River, then NW along the Shakwak
Trench. At TF offsets of between 230 and 430 km, our models illustrate that a substantial amount of the paleo Yukon River drainage may have flowed eastward into the continental interior via an ancestral Liard River. We interpret the drainage
reversals convincingly attributed to the effects of Pliocene glaciation as merely an overprint on far more ancient Yukon River reversals attributed tectonic displacements along the TF in the early Cenozoic. |
| GEOSCAN ID | 321644 |
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