A new series of detailed magnetic anomaly maps has been produced for the Atlantic onshore and offshore regions of Canada. The maps are based on a new compilation of aeromagnetic and marine survey data collected by government and industry surveyors over the past several decades. Individual surveys and digital grids have been adjusted to a common datum and micro-levelled to minimize textural artifacts. High-elevation regional survey flights were used to define a standard long-wavelength component (200 to 400 km) for levelling. A 500 m grid was produced from the reprocessed data and artificial illumination has been used to enhance subtle anomalies and trends in the maps.

The new series of 4 maps consists of a regional map at 1 : 3 000 000 scale and three local maps at 1 : 1 500 000 scale covering Nova Scotia, Newfoundland & the Gulf of St. Lawrence, and the Grand Banks. Subtle features that are visible in the new maps include major mafic dikes cutting across Nova Scotia, the Avalon peninsula of Newfoundland, and the shelf northeast of Newfoundland. Also visible are details of near-surface basement structures on the Scotian shelf, Grand Banks and Flemish Cap. Micro-levelling has improved the continuity of anomalies crossing shorelines and details of onshore features are easily followed into the offshore domain in many areas.

The maps will be released as GSC Open Files in 2003 and copies may be obtained from the Geological Survey of Canada (Atlantic) office or other GSC product distribution centres.