Marine geological and geotechnical investigations in Wellington, Byam Martin, Austin, and adjacent channels, Canadian Arctic Archipelago

Abstract

Marine geological and geophysical investigations were carried out in Wellington Channel, Byam Martin and Austin channels, and in eastern Barrow Strait-western Lancaster Sound from CSS HUDSON in i986. These investigations provided information on the distribution, thickness, composition, depositional environments, geotechnical properties, and regional geological setting of the surficial sediments, and on the structure of the near surface bedrock. The data indicate the widespread occurrence of sediments of apparent glacial origin (glacial drift) which overlie variably dipping sedimentary bedrock, and which are in turn locally overlain by up to a few metres of acoustically stratified and acoustically transparent sediments, interpreted to represent glaciomarine and postglacial sediments respectively. The drift unit locally forms constructional features interpreted to be moraines, and in places contains multiple sequences. Surficial sediment thicknesses in Wellington Channel commonly are less than JO m but locally reach 25 m, are somewhat greater in Byam Martin and Austin channels (up to 50 m), and are generally greater in eastern Barrow Strait, where they locally reach iOO m. Geotechnical, foraminiferal and textural data show consistent correlations with one another and with the acoustic stratigraphic units. The postglacial sediments have a high water content, low bulk density, and low shear strength; the converse applies to the glaciomarine and glacial drift sediments. Foraminifera are relatively diverse in the postglacial sediments, less diverse in the glaciomarine sediments, and are absent in the glacial drift. Magnetic susceptibility data suggest that most of the sediments probably were derived from Paleozoic rocks of the Arctic islands, but that glacial drift in northern Prince Regent inlet and glaciomarine sediments in eastern Barrow Strait-western Lancaster Sound may have been derived partly from Precambrian rocks bordering part of the Gulf of Boothia, south of Prince Regent Inlet. Some seafloor sediments, particularly the glacial drift, have been modified by ice scour.

The Quaternary History of Cumberland Sound, Southeastern Baffin Island: The Marine Evidence

“…This scenario was used to explain the supposed limited ice flow into Cumberland Sound during the Late Foxe (Dyke, 1979). This study shows that a major ice lobe did fill Cumberland Sound in the Late Foxe, and that there was a relatively large carbonate influx associated with melting of the ice (Jennings, 1989). Possibly, the ice divide lay to the west of the Precambrian/ Paleozoic contact for part of its length or it migrated across that contact over some time intervals.…”

“…82034-041 PC lies > 20 km inside of the zone of Tertiary bedrock, landward of the shallowest areas in this part of the shelf and is thus in a position to test the shelf-ice hypothesis. Smectite does not dominate the mineralogy of the extreme ice-proximal sediments of 82034-041 PC (Jennings, 1989). Instead, kaolinite and mica, products of erosion of the Cretaceous bedrock within Cumberland Sound dominate the sediment in this core.…”

“…At 9750 BP, lithofacies B was replaced by lithofacies C. This textural change corresponds with a relative increase in the carbonate content, an increase in magnetic susceptibility, a decrease in organic carbon and a color change from black/ gray to gray (Table II; Jennings, 1989). These changes are interpreted to reflect the retreat of the grounding line onto Precambrian bedrock (Fig.…”

“…First, 81.5 cm were added to the depths in the piston core. This is the best estimate of the depth of sediment bypassed by the piston core during coring (Jennings, 1989). The sediment age at the top of the depthcorrected section was assumed to be modern.…”

Late Quaternary Marine and Terrestrial Environments, Northwestern Baffin Island, Northwest Territories

“…The modern distribution of live agglutinated and calcareous species appears to be controlled by differences in water masses, e.g. temperature, salinity, ice cover, availability of calcium carbonate (Vilks, 1969;Greiner, 1974;MacLean et al, 1989;Hunt and Corliss, 1993). Agglutinated faunas record a broad regional signal and the establishment of modern océanographie conditions -i.e., cold, less saline Arctic waters -after 6000 BP in many sites.…”