Geological features of the northeastern Canadian Arctic margin revealed from analysis of potential field data

Abstract

The northeastern Canadian Arctic margin is bordered to the north by Alpha Ridge, a dominantly magmatic complex within the Amerasia Basin of the Arctic Ocean, which forms

Exhuming the Top End of North America: Episodic Evolution of the Eurekan Belt and Its Potential Relationships to North Atlantic Plate Tectonics and Arctic Climate Change

“…Finally, the Paleocene age group indicates a rapid exhumation pulse at a rate of ≥0.4 km/Myr prior to sediment deposition. We interpret this rapid exhumation as reflecting a generally extensional period related to crustal thinning and tectonic denudation rather than tectonic uplift, because (i) it is coeval with basin formation and deposition in a coastal marine environment (as indicated by the palynology data) and, thus, with subsidence of parts of the continental margin, and (ii) it coincides with a period of crustal extension from Late Cretaceous‐Cenozoic times proposed by interpretation of aeromagnetic and gravity data for the northeastern Canadian Arctic margin (Anudu et al, ) and also predicted between 63 and 55 Ma by GPlates modeling (Gion et al, ; Harrison, ). Crustal thinning may have caused transtensional reactivation of preexisting fault zones, locally leading to pull‐apart(?)…”

“…Assuming geothermal gradients between 20 and 40 °C/km, average denudation rates for the lag time can be estimated between 0.85 and 0.25 km/Myr. Since denudation was presumably related to crustal extension/transtension (Harrison, ; Anudu et al, ; Gion et al, ; see also discussion on the pre‐Eurekan evolution), we consider a higher geothermal gradient to be more realistic and thus estimate denudation rates of ~0.45 to 0.25 km/Myr for the Paleocene, pre‐Eurekan stage, that is, for the time between isotopic closure (~63 Ma) and sediment deposition (~56 Ma). The increasing lag time and decreasing cooling rates from early to late Paleocene argue for an episodic high exhumation pulse during the Early Paleocene.…”

“…Paleogeographic reconstruction of the study area and its surroundings compiled after Lundin and Doré (), Mosar et al (), Gaina et al (), Tessensohn and Piepjohn (), Gernigon et al (), Oakey and Chalmers (), Piepjohn et al (, ), Anudu et al (), Gion et al (), and Newton and Huuse (). For reference, the present‐day position of Greenland is shown in yellow.…”

“…pre‐Eurekan stage ; Piepjohn et al, ). The Canadian Arctic must have experienced significant (trans)extension from the Late Cretaceous till at least the end of the Paleocene, as suggested by interpretations of structural data along the Nares Strait (Piepjohn et al, ) and of potential field data from the westernmost Ellesmere and Axel Heiberg islands (Anudu et al, ). An extensional regime in the Paleocene has also been assumed for a GPlates model (Gion et al, ), providing reconstructions with an estimated value of ~85 km of extension between Ellesmere and Devon Islands and of ~20 km of extension between Ellesmere and Axel Heiberg Islands (Harrison, ).…”

“…During the Cretaceous, northern Ellesmere Island was affected by intense intrusive and extrusive mafic to felsic magmatism, including mafic dykes and the Wootton Intrusive and Hansen Point Volcanic complexes, related to the High Arctic Large Igneous Province (e.g., Embry & Osadetz, ; Estrada et al, 2016; Ricketts et al, ; see Figure a). Cretaceous magmatism has been documented in a wide area, including the offshore Alpha Ridge area to the north, and is interpreted to be associated with a mantle plume (Anudu et al, ; Embry & Osadetz, ; Estrada et al, , ; Piepjohn et al, ; Ricketts et al, ).…”