I. Zietz
L.R. Alldredge
E. R. King
1966
<p><span>A study of 23,000 miles of total intensity aeromagnetic profiles in the </span>central<span> </span>Arctic<span> has been made by the U. S. Geological Survey and the U. S. Coast and Geodetic Survey. The profiles were flown at 20,000 feet above sea level and cover approximately 1,350,000 square miles of the </span>Arctic<span> Ocean between the North Pole and the North American continent. When the profiles are smoothed to remove crustal anomalies, the resulting contoured values differ from the U. S. Hydrographic Office Chart 1703 N for 1955 corrected to 1951 by as much as 2000 gammas in the northern part of the </span>Arctic<span> Archipelago. A nondipole regional focus east of Greenland has decreased in amplitude but has changed very little in position since 1907.5. There is a profound difference in the </span>magnetic<span> characteristics of the rocks on either side of the underwater Lomonosov Ridge across the </span>Arctic<span> Ocean. In the Eurasian Basin the high-altitude profiles are relatively smooth or show only minor anomalies, but on the North American side of the ridge there is a large area of closely spaced, high-amplitude anomalies which has been designated the </span>Central<span> </span>Magnetic<span> Zone. Although the anomaly trends parallel the Alpha Rise, this zone is far more extensive, including nearly half of the Canadian Basin on one side and probably all the </span>Central<span> </span>Arctic<span> Basin on the other side of the rise. The Lomonosov Ridge is marked by a persistent anomaly of moderate size that indicates the presence of </span>magnetic<span> material in the ridge. Probable block-fault structures along the flanks of the Alpha Rise are associated with blocklike </span>magnetic<span> anomalies of comparable widths. A characteristic </span>magnetic<span> pattern occurs over an area of jagged bottom topography in the Eurasian Basin. A similar </span>magnetic<span> pattern over part of the Lena Trough may indicate another area of jagged topography. The belt of epicenters associated with the Mid-Atlantic Ridge continues through this rugged part of the Eurasian Basin, but the absence of the typical high </span>magnetic<span> anomaly makes it doubtful that the mid-oceanic ridge extends through this part of the </span>Arctic<span>. </span>Magnetic<span> </span>data<span> indicate that the thick sections of sedimentary rocks in the Paleozoic geosynclinal belts of northern Ellesmere Island and northern Greenland continue out under the adjacent continental shelves north of Greenland, west of the </span>Arctic<span> Archipelago, north of the part of Alaska east of Barrow, and under part of the Chukchi Shelf, and that they make up the bulk of the Nansen Swell off Spitsbergen. Thick sedimentary fill is indicated in the magnetically flat areas of the Eurasian Basin next to the Lomonosov Ridge and in the southern part of the Canadian Basin. The </span>magnetic<span> profiles on the Eurasian side of the Lomonosov Ridge closely resemble typical </span>magnetic<span> profiles over both Atlantic and Pacific oceans, where as the profiles of the </span>Central<span> </span>Magnetic<span> Zone on the North American side of the Lomonosov Ridge are completely unlike the oceanic </span>data<span> and show a striking similarity to typical profiles over the Precambrian rocks of the Canadian Shield and its buried equivalent under the </span>Central<span> Stable </span>Region<span> of the United States. Therefore, it is concluded that the </span>Arctic<span> </span>region<span> consists of a probable oceanic area on the Eurasian side and a basin formed by downdropped continental rocks, presumably a Precambrian complex similar to that of the Canadian Shield, on the North American side of the ridge. </span></p>
application/pdf
10.1130/0016-7606(1966)77[619:MDOTSO]2.0.CO;2
en
Geological Society of America
Magnetic data on the structure of the central Arctic Region
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