Magnetic Profile Across the Grand Banks and Flemish Cap Off Newfoundland

Abstract

This paper describes an aeromagnetic profile from Prince Edward Island, through the Cabot Strait to the Tail of the Grand Banks of Newfoundland, and subsequently over the Flemish Cap. It is inferred that Burgeo Bank off the southwest coast of Newfoundland is possibly a granite intrusion of Devonian age. A distinct magnetic anomaly, approximately 400 gammas in amplitude, appears to be associated with the edge of the continental shelf at the Tail of the Bank. A series of sharp shallow-source magnetic anomalies was recorded over the Flemish Cap, and this feature appears to have a negatively polarized core whose long dimension is oriented in a NNW.-SSE. direction.

Site 111

“…Flemish Cap was ignored by Bullard et al (1965) in their reconstruction of the Atlantic but it has attracted considerable interest since then. An early overflight (Hood and Godby, 1965) showed a central core of high intensity, short wavelength magnetic anomalies that indicated a shallow basement with thicker sediments to the west. Grant (in press) has interpreted profiler work and shown sedimentary beds prograding outwards from a seismically hard central core and being truncated at the shelf edge.…”

Aeromagnetic reconnaissance of the Labrador Sea

“…Naval Oceanographic Office sea magnetometer data to join the trends in the western magnetic zone in the Labrador Sea. Further data are obviously needed to confirm or deny this supposition, which, if confirmed, would indicate that the Appalachian system cannot extend any farther than the continental slope, and it would be additional support to the contention that the Flemish Cap is oceanic in origin [Hood and Godby, 1965 ...... 500 ....... I000 ....... 1500 ......... [1964] noted that a broad gravity low appeared .to be associated with the mid-ocean canyon in .the Labrador Sea. One epicenter is located on the Labrador shelf [Smith, 1964] and, in view of the uncertainty in location, might be associated with .the fault system proposed by Holtedahl [ 1958].…”