| The East Point magnetic anomaly (EPMA), in the southern Gulf of St. Lawrence, is approximately 50 km wide and 150 km long, strikes east-west, and has an amplitude on the order of 500 nT. The presence of the EPMA complicates tectonostratigraphic interpretations between Cape Breton Island and mainland Nova Scotia and New Brunswick. The second vertical derivative magnetic anomaly map shows several separate anomalies within the EPMA, termed the east magnetic anomaly (EMA), the central magnetic anomaly (CMA), the west magnetic anomaly (WMA), and the Mabou Highlands magnetic anomaly (MHMA). The Bouguer gravity map of the region indicates a relative gravity high, on the order of 12 mGal, coincident with the MHMA. Physical property measurements indicate high magnetic susceptibility and high density values for Late Precambrian to Paleozoic igneous and metamorphic units in the Mabou Highlands that are likely the source of the MHMA. Forward-modelling, with constraints from seismic and petrophysical data, established that the source of the MHMA extends approximately 12 km west of the Highlands, into the offshore domain at approximately 2.5 km depth. (Abstract shortened by UMI.)... |
