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The AAPG/Datapages Combined Publications Database

CSPG Special Publications

Abstract


Canada's Continental Margins and Offshore Petroleum Exploration — Memoir 4, 1975
Pages 433-451
Baffin Bay Margins

Aeromagnetic Reconnaissance of Davis Strait and Adjacent Areas

Peter Hood, Margaret Bower

Abstract

A low-level aeromagnetic reconnaissance of the Davis Strait area has been carried out as part of a co-operative aeromagnetic project between the National Aeronautical Establishment and the Geological Survey of Canada in order to throw additional light on the geological history of the region. The basaltic lavas in Davis Strait produce sharp distinct anomalies which alternate positively and negatively with an amplitude of several hundred gammas. Using this pattern recognition criterion it has been deduced that a considerable area of basalt exists offshore in Davis Strait being much larger in area than that exposed onshore. A zone of sharp anomalies strikes in a southwesterly direction from Disko Island in west Greenland towards Hudson Strait and appears to mark the location of a transform fault that formed one arm of an unstable RRF triple junction which was active for about 20 million years during the Eocene near the entrance to Hudson Strait. Similar unstable RRF triple junctions were located in the vicinity of Disko Island and near the entrance to Lancaster Sound and the combined effect of these was to separate Greenland and Canada by about 400 km. In each of the three cases a graben formed one arm of the RRF triple junction. The aeromagnetic reconnaissance also provided definite geophysical evidence that Cumberland Sound is a graben containing more than 8 km of sediment, and additional total field profiles were obtained to better delineate the Melville Bay graben which appears to be an aulacogen. The profiles indicate that the Melville Bay graben bends sharply to the west at its northern end, passes south of Cape York and continues in the general direction of Smith Sound. As part of the 1974 field operation a more detailed survey was made of a part of Smith Sound. The resultant profiles have the typical U-shaped form of a deep east-southeast striking graben and in excess of 20 km of sediments are present in the graben.


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