Christopher T. Dale

The Late Quaternary sediments of the northeast Newfoundland continental shelf have been examined and mapped as five surficial seismic facies. Airgun seismic data show constructional glacial features generally occur below the 200 m isobath. Variations in sedimentological and geotechnical parameters in six cores within the area of seismic coverage have provided the basis for correlations between Huntec Deep Two System (D.T.S.) seismic data and sedimentary facies. Sedimentological analyses indicate both glacial and post-glacial sediments have been recovered. The last major glacial advance in this area has been tentatively dated as approximately 25,000 yBP.

A seismically stratified facies on the D.T.S. data has been attributed to spatially coherent layers of ice-rafted material. This ice rafting is suggested as having occurred during the cold period on the eastern Canadian seaboard, corresponding to the Late Wisconsinan period of continental ice advance.

Comparisons between D.T.S. seismic data and synthetic seismograms have made possible the conclusions that shot to shot incoherencies on D.T.S. data are probably due to local variations in geology, geotechnical results from singular piston core samples are unrepresentative of the "average" geology observed with the D.T.S., and geological studies require a knowledge of the subsurface seabed acoustic impedance structure if an undisputable interpretation is to be made of the high resolution seismic data.

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Pages: 191
Supervisor: R. Haworth