Provenance, U-Pb detrital zircon geochronology, Hf isotopic analyses, and Cr-spinel geochemistry of the northeast Yukon-Koyukuk Basin: Implications for interior basin development and sedimentation in Alaska

Abstract

21The Yukon Koyukuk Basin is a large depression that covers ~118,000 sq. km in 22 western interior Alaska that is divided into two sub-basins by a volcanic arc assemblage. Sedimentary basins that flank orogenic belts serve as archives that record the 58 long-term deformational and uplift history of orogenic systems. When associated with a 59 topographic effect, the kinematic evolution of an orogen affects the geometry, filling 60 pattern, and provenance signature of the adjacent synorogenic sedimentary basins 61 (Bayona, et al., 2008). Processes such as tectonic uplift and surficial denudation, rainfall, 62 sediment supply, sediment transport and dispersal have direct implications on the 63 evolution of synorogenic sediment routing systems (Whitchurch et al., 2011). As 64 observed in several Cenozoic orogenic belts (e.g. Himalayas and Andes), differences in 65 sedimentary filling patterns are recognizable by variations in large-scale axial and 66 transverse river systems and smaller transverse rivers observed draining into and within 67 the foreland and hinterland basins separated by an orogenic high (Burbank et al., 1996; 68 Clark et al., 2004; DeCelles, 2012; Dietze et al., 2014; Hessler and Fildani, 2015). This 69 4 variation in drainage systems leads to differences in provenance signatures recorded 70 within the basin sediments (Lease et al., 2007; Bayona, et al., 2008; Cina, et al., 2009; 71 DeCelles et al., 2014). Therefore, the provenance signature of the sediments that occupy 72 these basins should help in understanding the evolution of the synorogenic sediment 73 routing systems on either side of the orogen. 74In northern Alaska, the latest Jurassic -Early Cretaceous Brooks Range orogen is 75 flanked by two synorogenic sedimentary basins, the northern Colville foreland basin and 76 southern Yukon Koyukuk Basin (Fig. 1). Renewed deposition of thick successions of 77 clastic rocks in the Colville Basin occurred coincidently with the formation of Yukon 78Koyukuk Basin, which led authors to conclude that these events were the result of 79 orogenic uplift of the Brooks Range (Molenaar et al., 1984(Molenaar et al., , 1986 Miller and Hudson, 80 1991;Till, 1992). Seismic reflection data collected within the Colville Basin delineate a 81 series of turbidite-dominated sedimentary packages that longitudinally filled the basin 82 from west to northeast from the late Early Cretaceous to the Cenozoic (Houseknecht et 83 al., 2009; Houseknecht and Wartes, 2013). Despite all the work performed in 84 characterizing the clastic rocks of the Colville Basin, little emphasis has been paid to 85 understanding the formation and sedimentary evolution of the southern Yukon Koyukuk 86 Basin. 87The Yukon Koyukuk Basin is a large wedge-shaped physiographic depression, 88 underlain by volcanic and marine sedimentary rock units, that covers ~118,000 sq. km 89 (Fig. 1) formed in a syn-collisional forearc setting (Till et al., 1993) to its formation during post-95 accretion lithospheric extension of the hinterlan...

Late Cretaceous‐Cenozoic Exhumation of the Western Brooks Range, Alaska, Revealed From Apatite and Zircon Fission Track Data

“…This simplified subterrane stratigraphy is adapted in mapping herein. The timing of early Brookian contractional tectonism was Middle Jurassic to Neocomian (e.g., Moore et al, 1994, and references therein); it was succeeded by Aptian-Albian extensional deformation and exhumation of the early Brookian hinterland (to the south of the present study area; Miller & Hudson, 1991;O'Brien et al, 2017). The early Brookian contractional Silberling et al (1992) and Moore et al (1994)).…”

Detrital zircon geochronology along a structural transect across the Kahiltna assemblage in the western Alaska Range: Implications for emplacement of the Alexander-Wrangellia-Peninsular terrane against North America

“…The Kahiltna assemblage in southern Alaska (Fig. 1) and associated basins along strike to the east and southeast (Nutzotin, Dezadeash, and Gravina basins) are part of a coeval group of thick, mostly deep-water, deformed mid-Cretaceous (115-80 Ma) basins (some with strata as old as Late Jurassic) in Alaska and northwestern Canada that includes the Kuskokwim basin (Cady et al, 1955;Box and Elder, 1992;Miller and Bundtzen, 1994;Kalbas, 2006), Yukon-Koyukuk basin (Patton and Box, 1989;Nilsen, 1989;O'Brien et al, 2017), Manley basin (Silberling et al, 1992;Weber et al, 1992), Kandik basin (Brabb and Churkin, 1969;Johnsson, 2000), Colville basin (Bird and Molenaar, 1992;Houseknecht et al, 2009), and the Eagle-Mackenzie basin (Miall, 1973;Schröder-Adams, 2014). Following Ingersoll (2012), we use the term "basin" to refer to an accumulation of sedimentary or volcanic rocks, with no inference as to its genesis or origin.…”

Greenschist Facies Metamorphic Zircon Overgrowths as a Constraint on Exhumation of the Brooks Range Metamorphic Core, Alaska

“…The up to ~4‐km‐thick Albian to Santonian (c. 113–84‐Ma) deep marine turbidite to continental clastic sedimentary package constituting the northern Yukon‐Koyukuk Basin (e.g., Nilsen, ; Figure b) is interpreted to have been deposited as the result of progressive unroofing of the Brooks Range orogenic core (Dillon & Smiley, ; Murphy et al, ; O'Brien et al, ; Patton Jr. & Box, ). Deep water deposits with fossils of Albian age (c. 113–100 Ma) and detrital zircons as young as 105 ± 5 Ma overlie shallow water volcanogenic strata having fossils as young as Aptian age (c. 126–113 Ma) and volcanic rocks with K‐Ar ages as young as 117 Ma (Patton Jr. et al, , and references therein; also, O'Brien et al, ). Major tectonic subsidence of the Yukon‐Koyukuk Basin is therefore bracketed to c. 126–100 Ma and overlaps with the growth of retrograde metamorphic zircon studied here (Figure c).…”

“…Geology simplified from Patton Jr. et al () and Wilson et al (). Zircon U‐Pb ages of Mesozoic magmatic rocks are compiled from Roeske et al (), Dillon et al (), Patton Jr. et al (), Dwight Bradley, written communication, 2010, as in Wilson et al (), Amato and Wright (), Richard Friedman, written communication, 2009, as in Till et al (), and O'Brien et al (). (c) Age comparison of decompression/retrogression‐related metamorphic zircon growth in the Brooks Range with major subsidence in the Yukon‐Koyukuk Basin and relative flux of felsic magmatism across interior Alaska and the Seward Peninsula.…”