Submarine glacial landforms on the Bay of Fundy–northern Gulf of Maine continental shelf

Abstract

The Bay of Fundy–northern Gulf of Maine region surrounds the southern part of Nova Scotia, encompassing, from west to east, the Bay of Fundy, Grand Manan Basin, German Bank, Browns Bank, Northeast Channel, and northeastern Georges Bank (Fig. 1a). During the last glacial maximum (~24–20 14C ka BP), the southeast margin of the Laurentide Ice Sheet (LIS) occupied the study area, the rest of the Gulf of Maine, and the continental Scotian Shelf off Atlantic Canada (see Dyke et al. 2002, Fig. 1; Hundert & Piper 2008, Fig. 16; Shaw et al. 2006, Fig. 8). Early mapping of the glaciated region on the Scotian Shelf using side-scan sonar imagery and seismic reflection profiles revealed topographic features interpreted to be recessional moraines indicative of retreat of the LIS (King et al. 1972; King 1996; Stea et al. 1998). Subsequently, multibeam sonar seafloor mapping of local-scale glacial landforms on the inner Scotian Shelf off Halifax, Nova Scotia (Fig. 1a) provided further information on the dynamics of the advance and retreat of the ice sheet (Loncarevic et al. 1994). Interpretation of seismic reflection profiles across Georges Bank revealed that the surficial sediment is a veneer of glacial debris transported to Georges Bank by the LIS during the late Pleistocene from continental areas to the north (Shepard et al. 1934; Knott & Hoskins 1968; Oldale & Uchupi 1970; Schlee 1973; Schlee & Pratt 1970; Twichell et al. 1987; Fader et al. 1988). Recent high-resolution multibeam sonar surveys of German Bank and the Bay of Fundy mapped a complex of ice-advance and ice-retreat features attributed to the activity of the LIS (Todd et al. 2007; Todd & Shaw 2012).