About This Item

Share This Item

The AAPG/Datapages Combined Publications Database

AAPG Bulletin

Abstract


Volume: 53 (1969)

Issue: 3. (March)

First Page: 739

Last Page: 739

Title: Arctic Margin of Canada: ABSTRACT

Author(s): Ernest F. Roots

Article Type: Meeting abstract

Abstract:

Recent investigations have added to knowledge of the northern margin of Canada and the structure of the Arctic Ocean. The geosynclinal belt rimming the North American craton has been deformed with a sequence and style of tectonism that in Paleozoic time were generally similar to those of the Appalachians and the Brooks Range, whereas the later history bears a resemblance to that of parts of the northwest cordillera.

Problems remain with regard to the possible extension of the geosynclinal belt and structures at each end of the present exposures in the Arctic archipelago. At its west end the belt trends beneath the continental shelf toward the Canada Basin; the magnetic and gravity patterns over the shelf and continental slopes are not clearly related to known structures. A major positive gravity anomaly along the outer edge of the shelf lies athwart the projection of known geologic trends, and possible explanations of this anomaly by crustal thinning or intrusions are not supported by available magnetic and seismic data. That this area is still active tectonically is suggested by the unusual depth of the shelf which appears to have been drowned since Quaternary time but is still isostatically ove -compensated, by magnetic and seismic anisotropy, modern microseismicity, and other features.

At its northeast end the geosynclinal belt of Arctic Canada abuts the geosynclines of northeast Greenland, whose faunal content and deformational history show European rather than American affinities since Paleozoic time. The relationship between these two provinces appears to be related to the evolution of the structures of the Arctic Ocean. Present evidence appears compatible with the hypothesis that the trans-Arctic Alpha Cordillera was connected with the Mid-Atlantic Ridge, and that the connection has been dislocated by the widening of the Atlantic basin, leading progressively to the development of Baffin Bay and the Nares rift valley, and to the extension of the Atlantic fracture into the Siberian crustal block, splitting off Lomonosov Ridge as a continental remnant that abuts ag inst, but does not join, the structures of Arctic Canada.

End_of_Article - Last_Page 739------------

Copyright 1997 American Association of Petroleum Geologists