Mesozoic paleogeographic and geodynamic evolution of northern Alaska : from Amerasian basin to brookian orogen

• Main Author: Lemonnier, Nicolas
• Other Authors: Institut des Sciences de la Terre de Paris (iSTeP), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Université Pierre et Marie Curie - Paris VI, Philippe Agard, Loïc Labrousse
• Format: Doctoral or Postdoctoral Thesis
• Language: French
• Published: HAL CCSD 2015
• Subjects: Canadian bassin; Brooks range; Regional geodynamics; Paléogéographique; Géodynamique; Bassin canadien; Datation; Thermique; [SDU.STU]Sciences of the Universe [physics]/Earth Sciences; Arctic; Canada; Pacific; Brooks Range; canada basin; Chukotka; Alaska
• Online Access: https://tel.archives-ouvertes.fr/tel-01359863; https://tel.archives-ouvertes.fr/tel-01359863/document; https://tel.archives-ouvertes.fr/tel-01359863/file/these_archivage_2702599o.pdf

The Canadian basin is among the few basins worldwide for which the nature and the geometry of the substratum, and therefore the opening mode, are still unknown. Paleogeographic models based on the few data available are subject to controversy, with different mechanisms and inception ages. According to current paleogeographic models, the margins of Canadian basin either considered as extensional or transform margins. Detailed study of their structures and chronologies is a preliminary exercise to discriminate between permissible models. The most sollicited opening model assumes a change of polarity of the overall subduction south to the canadian basin during the multiphase Brookian orogeny.The Brooks orogen is located north of the alaskan peninsula and south of the canadian basin. It constitutes one of the main assembly stage of terranes in the Northern Cordillera : docking of the Arctic-Alaska-Chukotka terrane with the peri-Pacific arcs system. Its collisional stage is deemed synchronous of the opening of the Canada Basin, which is likely to provide clues about the coupling between tectonics of the north basin and intra-Alaska Cordillera deformation. This orogen has both recorded and influenced the geodynamic history of the Canadian basin. The relative chronology of the development of the two structures is essential and any reconstruction of regional geodynamics must reconcile them in terms of kinematics and boundary conditions. Le bassin canadien figure parmi les rares bassins au monde dont la nature et la géométrie du substratum, et donc le mode d'ouverture, ne sont aujourd'hui pas connus. Les modèles paléogéographiques contraints par les rares données disponibles sont sujets à des interprétations controversées avançant des mécanismes et des âges d'ouverture différents, voire contradictoires. Selon les modèles paléogéographiques proposés, les marges du bassin canadien sont tantôt extensives, tantôt transformantes. L'étude de leurs structures et de leurs histoires détaillées est un exercice préalable à la ...