Detailed aeromagnetic investigation of the Arctic Basin: 2

Abstract

Over 150,000 line‐kilometers of low‐level (152 m) aeromagnetic data were recorded in the western Arctic Basin by the U.S. Navy during four field seasons (1975–1978); data from the first 2 years were presented by Vogt et al. (1979a), while the data from the last two years are described in this paper. These data (1977–1978) cover a swath from the north slope of Alaska to the north geographic pole. Flight lines were spaced between 10 and 24 km. The east‐west oriented aeromagnetic profiles across the Canada Basin and the Beaufort Sea suggest that Alaska was moving away from the Queen Elizabeth Islands of the Canadian Arctic from 153 m.y. B.P. (anomaly M‐25 time) to 127 m.y. B.P. (M‐12), at an opening rate of 2.6 cm/yr. An extinct spreading center is defined by a positive free‐air gravity anomaly, with the relic spreading axis generally paralleling the 150°W meridian. We are unable to recognize a coherent pattern of lineated anomalies over the Alpha Ridge; therefore its origin remains uncertain. A series of seafloor spreading type anomalies have been tentatively identified in the Fletcher (Makarov) Basin. Spreading began in the Upper Cretaceous (anomaly 34; 80 m.y. B.P.) and continued until mid‐Eocene (anomaly 21; 53 m.y. B.P.); total opening rate was about 1.7 cm/yr. During the opening of the Fletcher Basin, rifting began in Baffin Bay and the Norwegian and Labrador seas and the Eurasian Basin. Our results suggest a tectonic coupling between these areas at this time, with the Nares Strait acting as a transform fault and serving as a connector with the Baffin Bay/Labrador Sea spreading centers.

Seismic and density structure of the lithosphere−asthenosphere system along transect Knipovich Ridge−Spitsbergen−Barents Sea – geological and petrophysical implications

“…Previously this region has been studied by geophysical surveys, in− cluding active and passive seismic experiments, gravity and magnetic (e.g. Vogt et al 1979;Taylor et al 1981;Sellevoll 1982;Davydova et al 1985;Faleide et al 1991;Klingelhöfer et al 2000a, b;Mjelde et al 2002;Breivik et al 2003;Ljones et al 2004;Czuba et al 2008). Most of the study area around Spitsbergen and in the Barents Sea has a water depth about 250 m only (Fig.…”

Geohazard assessment from satellite magnetic data modeling—with examples from the Arctic Margin along the Canada Basin and the Korean Peninsula along 40°N (latitude) parallel

“…The localizations of four poles of rotation for the opening of the Canada Basin have been proposed. The lower case letters indicate the proposed pole of opening as given by the referenced authors: (a) Taylor et al (1981); (b) Grantz et al (1979); (c) Grantz et al (1990); (d) Norris (1983). The heavy dashed line indicates the trend of the Magsat anomaly through this region.…”

“…Based on low-level aeromagnetic profiles, Taylor et al (1981) suggested that the Canada Basin was formed by a rotational spreading event beginning in Late Jurassic (M-25) and continuing until Early Cretaceous (M-12). This scissors-like opening of the Canada Basin was first proposed by Carey (1955) and developed by Tailleur (1973).…”

“…Several re- searchers have calculated the pole of rotation to be in the MacKenzie River Delta region. Extending the aeromagnetic anomalies of Taylor et al (1981) back to their convergence point would place the axis of rotation at approximately 69.25…”

K-Ar ages of Basaltic rocks collected during a traverse of the Frans Josef Land Archipelago (1895-1896)

“…The volcanic ages would suggest another pulse at approximately 120 ma (see Green et al 1984) with active sea floor spreading commencing in the western Arctic (Taylor et al 1981). This increased volcanism at 120 ma is well established on a global scale (Campsie et al 1984 and references therein).…”