Significance of Northeast‐Trending Features in Canada Basin, Arctic Ocean

Abstract

Synthesis of seismic velocity, potential field, and geological data from Canada Basin and its surrounding continental margins suggests that a northeast‐trending structural fabric has influenced the origin, evolution, and current tectonics of the basin. This structural fabric has a crustal origin, based on the persistence of these trends in upward continuation of total magnetic intensity data and vertical derivative analysis of free‐air gravity data. Three subparallel northeast‐trending features are described. Northwind Escarpment, bounding the east side of the Chukchi Borderland, extends ∼600 km and separates continental crust of Northwind Ridge from high‐velocity transitional crust in Canada Basin. A second, shorter northeast‐trending zone extends ∼300 km in northern Canada Basin and separates inferred continental crust of Sever Spur from magmatically intruded crust of the High Arctic Large Igneous Province. A third northeast‐trending feature, here called the Alaska‐Prince Patrick magnetic lineament (APPL) is inferred from magnetic data and its larger regional geologic setting. Analysis of these three features suggests strike slip or transtensional deformation played a role in the opening of Canada Basin. These features can be explained by initial Jurassic‐Early Cretaceous strike slip deformation (phase 1) followed in the Early Cretaceous (∼134 to ∼124 Ma) by rotation of Arctic Alaska with seafloor spreading orthogonal to the fossil spreading axis preserved in the central Canada Basin (phase 2). In this model, the Chukchi Borderland is part of Arctic Alaska.

Age of the Canada Basin, Arctic Ocean: Indications From High‐Resolution Magnetic Data

“…Therefore, the crustal age of the Canada Basin could be 139. according to the MHTC12 (GTS2012), and seafloor spreading occurred between Berriasian and early Hauterivian ( Figure S6). The rifting direction in strike-slip models is shown in dashed arrow along the eastern boundary of the Northwind Ridge (Døssing et al, 2018;Hutchinson et al, 2017). Seafloor spreading is slightly asymmetrical, with rates 5% faster on the western flank.…”

“…Among them, the generally accepted anticlockwise rotation model proposes that the Chukotka-Alaska region rotated from Arctic Canada with a pole of rotation located near the Mackenzie Delta in Early Cretaceous (Carey, 1955;Embry, 1990Embry, , 2000Embry & Dixon, 1990;Grantz et al, 1998Grantz et al, , 2011Halgedahl & Jarrard, 1987;Mickey et al, 2002). However, this model is challenged by alternative models (e.g., Chian et al, 2016;Døssing et al, 2018;Hutchinson et al, 2017;Koulakov et al, 2013;Lane, 1997), in part due to the uncertain age of the Amerasia Basin. The extent of oceanic crust and location of the relict axis are broadly consistent with the depictions in the rotation model.…”

“…The CM13n and negative polarity intervals between CM9 and CM11 are associated with the low-amplitude magnetic high (SN1) intervening N1 and N2 and the low-amplitude magnetic low (SR1) near the center of N1, respectively. Since the position and geometry of the Chukchi Borderland in Mesozoic remain controversial (Grantz et al, 1998;Hutchinson et al, 2017;Miller et al, 2006), we only place the CBL in (c) according to its present configuration. Near 75°N, the associated full spreading rate was~32 (38) mm/year at the beginning of spreading and slowed down to~30 (30) mm/year in the last~3 Ma before the cessation.…”

“…The extent of oceanic crust and location of the relict axis are broadly consistent with the depictions in the rotation model. However, this model is challenged by alternative models (e.g., Chian et al, 2016;Døssing et al, 2018;Hutchinson et al, 2017;Koulakov et al, 2013;Lane, 1997), in part due to the uncertain age of the Amerasia Basin.…”

“…Since the position and geometry of the Chukchi Borderland in Mesozoic remain controversial (Grantz et al, 1998;Hutchinson et al, 2017;Miller et al, 2006), we only place the CBL in (c) according to its present configuration. The rifting direction in strike-slip models is shown in dashed arrow along the eastern boundary of the Northwind Ridge (Døssing et al, 2018;Hutchinson et al, 2017). Note the northeast-trending strike slip is subparallel to the subduction zones in the SAO, which may require a new explanation about the dynamic relationship between them.…”