Circum-Arctic Structural Events: Tectonic Evolution of the Arctic Margins and Trans-Arctic Links with Adjacent Orogens

The circum-Arctic region has received considerable attention over the past several decades with vigorous debate focused on topics such as mechanisms for opening the Eurasian and Amerasian basins, the importance of plume-related magmatism in the development of the Arctic Ocean, and mechanisms for ancient terrane translation along the Arctic margins. In recognition of the 25th anniversary of the Circum-Arctic Structural Events (CASE) program, an international polar research effort organized and led by the Bundesanstalt für Geowissenschaften und Rohstoffe (BGR) of Germany, this volume presents results from 18 major field expeditions involving over 100 international geoscientists from a broad spectrum of disciplines. The resulting publication focuses on the Proterozoic to Cenozoic tectonic evolution of the circum-Arctic region with correlations to adjacent orogens.
Unravelling the thermal evolution of the Neruokpuk Formation in the British Mountains, North Yukon, Canada: Tectonic and orogenic implications
*Present address: TOTAL, CSTJF, Avenue Larribau, 64018 Pau, France.
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Published:June 14, 2019
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CiteCitation
Maelianna Bigot-Buschendorf, Frédéric Mouthereau, Loïc Labrousse, Charlotte Fillon*, Konstanze Stübner, Matthias Bernet, 2019. "Unravelling the thermal evolution of the Neruokpuk Formation in the British Mountains, North Yukon, Canada: Tectonic and orogenic implications", Circum-Arctic Structural Events: Tectonic Evolution of the Arctic Margins and Trans-Arctic Links with Adjacent Orogens, Karsten Piepjohn, Justin V. Strauss, Lutz Reinhardt, William C. McClelland
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ABSTRACT
Defining temporal and spatial distribution of shortening is critical to reconstruct past plate motions and to examine mechanical coupling processes at convergent plate boundaries. Understanding the collisional evolution of the British Mountains and Beaufort-MacKenzie basin in the northern Alaska–Yukon region is key for the geodynamics of the Arctic region. With the aim to resolve the exhumation history of this region, we present the first zircon fission-track and (U-Th)/He analyses on apatite and zircon from the Neruokpuk Formation (ca. 720–485 Ma), which forms the orogenic basement of the British Mountains. Zircon fission-track ages show partial resetting, indicating the Proterozoic basement did not reside at temperatures above 240 °C. Thermal modeling of zircon and apatite (U-Th)/He data indicates that our samples reached this maximum temperature at ca. 100 Ma. The onset of the Brookian collision is indicated by exhumation from ca. 80 Ma. A total exhumation of 7–8.5 km since the Late Cretaceous is inferred. Apatite (U-Th)/He ages of ca. 50 Ma show that exhumation was less than 2.5 km since the early Eocene. We infer from a comparison with the temporal evolution of exhumation from adjacent orogenic domains that shortening progressively shifted northward from the British Mountains to the Barn Mountains and offshore in the Beaufort Sea during the Paleocene. Along-strike variations in the architecture of the rifted margin of Arctic Alaska is suggested to have exerted a strong control on the structural styles and observed exhumation patterns.
- absolute age
- Arctic Ocean
- Beaufort Sea
- Canada
- Cenozoic
- depositional environment
- Eocene
- exhumation
- fission-track dating
- geochronology
- low temperature
- one-dimensional models
- orogeny
- Paleogene
- plate tectonics
- rifting
- tectonics
- temperature
- Tertiary
- thermal history
- thermochronology
- (U-Th)/He
- Western Canada
- Yukon Territory
- Neruokpuk Formation
- Sedgwick Pluton
- British Mountains