Quaternary geology of the southeast Baffin Island continental shelf

Abstract
The Quaternary sediments of the southeast Baffin lsland continental shelf have been investigated using acoustic data (Huntec DTS and 655 cm 3 air gun seismic profiles, sidescan sonograms, echograms) supplemented by sample control (grabs and cores). Four acoustic units have been defined and informally named: ( 1) Baffin Shelf Drift - unstratified diamictons generally < 100 m thick but up to 300 m off Hudson Strait, which were deposited {rom grounded glacial ice, and which reach to the shelf edge in some areas; these sediments record repeated advances of glacial ice, of varied extent, of early Late Foxe and older age; (2) Davis Strait Silt - sediments generally < 10 m but up to 70 m thick, which are stratified where unscoured by grounding icebergs (subunit A) and acoustically unstratified where scoured by grounding icebergs (subunit B); these sediments record deposition {rom mid-Foxe to Holocene time and contain microfossil evidence of ice-proximal to ice­distal glacial marine environments; (3) Tiniktartuq Silt and Clay - stratified basin-fill sediments up to 10 m thick which directly overlie the stratified sediments of Davis Strait Silt subunit A; these sediments indicate a change in depositional style in the late Foxe to Holocene; (4) Resolution lsland Lag - subangular gravels and sands which occur in areas that appear largely devoid of caver to the limit of acoustic resolution (30-50 cm), and which may include areas of exposed bedrock; these sediments record current winnowing of areas of thin to discontinuous Baffin Shelf Drift or Davis Strait Silt. There is no evidence for a transgressive zone marking a relative sea level lowstand in the depths represented by the data (mainly > 150 m). The immediate seabed of the southeast Baffin Shelf has been subjected to modification by currents in the Holocene, resulting in the formation of an extensive surface veneer which overlies the sediments of the acoustic units in thicknesses < 30-50 cm.