Quaternary geology and surficial sediment processes, Browns Bank, Scotian Shelf, based on multibeam bathymetry

Browns Bank is located on the glaciated continental shelf off southern Nova Scoria. Geological mapping of Browns Bank is based on interpretation of multibeam bathymetric and backscatter data, in conjunction with 220 line km of seismic reflection profiles and sidescan sonograms, sea-floor sediment samples and bottom photographs. The Fundian Moraine, part of the previously identified end moraine system on the continental shelf off Nova Scotia, is a prominent west-east, flat-topped. multi-lobate ridge identifiable in the multibeam bathymetric data and in geophysical records. The Fundian Moraine was subjected to erosion in the surf zone during sea-level rise in depths less than 100 m. A series of north-south, roughly parallel till ridges, continuous in the subsurface with the Fundian Moraine, is interpreted as interlobate moraines suggesting formation by a tidewater glacier. The Browns Bank Moraine, connected to the Fundian Moraine, is evidence of a newly identified grounded ice position farther seaward than the latter. Bedforms, including obstacle marks, comet marks, sand waves and megaripples, are evidence of a vigorous anticyclonic current pattern on Browns Bank. The combination of multibeam bathymetric imagery with high-resolution geoscientific information represents a powerful technique for sea-floor geological investigations. (C) 1999 Elsevier Science B.V. All rights reserved.