ABSTRACT: Geomorphology and bedrock geology of southern Norwegian Bay, Queen Elizabeth Islands, Northwest Territories

CGRG Bibliography of Canadian Geomorphology
Search Results

Author :

Date :

Title :

Publication :

Issue :

Page(s) :

Abstract

This report presents marine geological information derived from echosounding and shallow seismic reflection surveys carried out in Norwegian Bay south of 77 30 N (Figure 1) in September, 1987 from CSS Baffin during BIO cruise 87-027, a collaborative program by the Canadian Hydrographic Service (CHS) and the Atlantic Geoscience Centre (AGC) (Praeg, 1987). Previous bathymetric information for this area was largely limited to spot soundings obtained through the near-perennial sea ice cover (CHS chart 7950). The regional bedrock geology is well-known from surface mapping of the adjacent islands (Balkwill et al., 1983), and from subsurface geophysical and well information (Hea et al., 1980), but the near-surface bedrock geology of Norwegian Bay was previously unreported. Bathymetric and geologic maps are presented at a scale of 1:250,000 (Sheets 1 to 3, attached). The bathymetric map (Sheet 1) is of a generalized nature and is not intended for navigation; color shaded relief plots of the bathymetry are also included in the report (Figure 2). The geologic maps present both surface (Sheet 2) and subsurface (Sheet 3) information. The report includes supporting information from the Panarctic et al. North Buckingham L-71 well (Figure 3), and from seismic reflection profiles (Sections 1 to 12). ... Sheet 1 and Figure 2 show that depths of less than 100 m extend offshore from the islands as shelves, and occur as banks in Belcher Channel and eastern Norwegian Bay. Shelves are especially prominent off Devon Island, and between North Kent and Graham islands where they form a sill that divides the bay into western and eastern basins. Figure 2 shows that the surfaces of the shelves are dissected by small channels, which in some cases separate small banks. Below 100 m shelves and banks give way to a series of troughs, in excess of 400 m deep in the western and eastern basins. The western basin is the convergence of troughs extending east from Belcher Channel, north from the area of Arthur Fiord, northwest from Cardigan Strait, and west from the sill between North Kent and Graham Islands. Cardigan Trough (informal name) is steep-sided with an irregular overdeepened floor locally over 350 m deep. The two adjacent troughs are broader and shallower, with irregular floors. Figure 2 shows that the shallowing of the basin and trough walls is marked by steep areas (or scarps) with 10's of metres relief, resulting in a stepped appearance. The western margin of the basin and the walls of Cardigan Trough are marked by especially prominent sets of scarps, with overall relief of 100's of metres. The eastern basin contains a prominent trough that deepens northeast from Hell Gate, and is connected to troughs to the east separated by two north-south ridges. The easternmost trough extends north along Ellesmere Island from the mouths of a group of fiords, and has depths of over 350 m. Section 2 shows that Hell Gate Trough (informal name) has prominent stepped walls, with total relief of 100's of metres. The smoother appearance of the eastern trough walls on Figure 2 largely reflects the local 2 km grid size, although bottom profiles do show that scarps are less common there despite relief of 100's of metres.

Bibliography of Canadian Geomorphology