Structural and kinematic evolution of the Yukon-Tanana upland tectonites, east-central Alaska: A record of late Paleozoic to Mesozoic crustal assembly

Middle Jurassic to earliest Cretaceous mid-crustal tectono-metamorphism in the northern Canadian Cordillera: Recording foreland-directed migration of an orogenic front

“…This domain is comparable to parautochthonous North American continental margin rocks (Lake George assemblage in Fig. 1) in east-central Alaska, which were exhumed from beneath the Yukon-Tanana terrane along mylonitic extensional faults in the mid-Cretaceous (Hansen, 1990;Hansen and Dusel-Bacon, 1998;Dusel-Bacon et al, 1995, 2002, 2006. Together, these data reveal a spatial and temporal pattern of structurally downward-younging deformation and metamorphism.…”

“…1) exhumed from beneath the Yukon-Tanana terrane along mylonitic extensional faults in the mid-Cretaceous (Hansen, 1990;Hansen and Dusel-Bacon, 1998;Dusel-Bacon et al, 1995, 2002, 2006. A parautochthonous North American origin for these rocks in east-central Alaska is based on Archean and Proterozoic U-Pb zircon inheritance and detrital ages, stratigraphic similarity with rocks in the Selwyn Basin, their structural position, and a lack of late Paleozoic arc assemblages characteristic of the Yukon-Tanana terrane Nelson et al, 2006;Dusel-Bacon and Williams, 2009).…”

“…Focused exhumation along the Australia Creek and Stewart River faults relative to the North River fault can explain the exposure of the youngest and deepest crustal level found in the Australia Mountain domain (9 kbar metamorphism) west (outboard) of the Finlayson Lake district (7.5 kbar metamorphism). Comparable exhumation of parautochthonous rocks of the Lake George assemblage occurred <200 km to the east in east-central Alaska (Dusel-Bacon et al, 1995, 2002Hansen and Dusel-Bacon, 1998).…”

End-Permian to mid-Triassic termination of the accretionary processes of the southern Altaids: implications for the geodynamic evolution, Phanerozoic continental growth, and metallogeny of Central Asia

“…The southern Altaids is a Precambrian-early Mesozoic orogenic belt that provides excellent information on accretionary processes, metallogeny and continental growth that are complementary to the younger Phanerozoic accretionary orogens in Mesozoic-Cenozoic Japan, Alaska and the American Cordillera (Sample and Fisher 1986;Haeussler et al 1995;Nelson 1996;Goldfarb et al 1997;Hansen and Dusel-Bacon 1998;Nokleberg et al 2005), and other accretionary orogens in the world Gray et al 2002;Glen et al 2007 Fig. 11 Schematic map of the Altaids showing principal mineral deposits which are linked to accretionary processes (modified after Seltmann and Porter 2005;Tang and Liu 1995;Han et al 2006a, b).…”

The Quaternary thrust system of the northern Alaska Range

“…The Hines Creek fault juxtaposes rocks of the Yukon-Tanana terrane (a Cretaceous metamorphic assemblage of Precambrian-Paleozoic metamorphic rocks and Mesozoic plutons [e.g., Pavlis et al, 1993;Hansen and Dusel-Bacon, 1998;Dusel-Bacon et al, 2004]) to the north, with Paleozoic to Paleogene rocks representative of marine environments to the south (Wahrhaftig et al, 1975). This fault also approximates a boundary between the rugged, recently glaciated terrain of the main axis of the Alaska Range and the northern foothills of the Alaska Range, which contain widespread Neogene deposits and landforms that span Quaternary time.…”