Richard McCallum

B. Sc. Honours Thesis

A Seismostratigraphic Analysis of High Resolution Seismic Reflection Data from the Western Grand Banks of Newfoundland

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A seismostratigraphic analysis of data from the western Grand Banks of Newfoundland has enabled the definition of seven acoustic units. Units were defined on the basis of high resolution, seismic reflection profiles, airgun reflection seismics, sidescan sonar, echograms, and bathymetric data. A sparse collection of piston cores, drill cores, vibrocores, and grab samples permitted limited lithologic correlation of these units. Unit 1 is acoustic basement of Hadrynian age and consists of pink and white quartzites, tillites, and granodiorite. Unit 2 is characterized by high intensity, continuous, coherent reflectors averaging 5 m penetration and consists of siltstones and sandstones of Cambrian to Devonian(?) age. Unit 3 is characterized by incoherent reflections with occasional coherent reflections dipping seawards at approximately 2-3o. Penetration averages 20 m and the unit consists of siltstones, mudstones, and sandstones of Cretaceous to Tertiary age. Units 1-3 represent the pre-Quaternary bedrock. Unit 4 has incoherent reflections and is interpreted as glacial till based on correlation with well-sampled areas from the Scotian Shelf. Unit 5 is defined by continuous, coherent reflections and is a rhythmically to wispily banded muddy sand to sandy mud dated at 22.015 (+1.35, -1.15) x 1000 y.B.P. Unit 6 is a zone of weak, discontinuous to continuous reflections generally forming veneer deposits of sand and gravel above depths of 110 m (60 fathoms). Unit 7 is characterized by weak to moderate intensity, continuous to discontinuous reflections with no banding and is interpreted as a clayey silty sediment.

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Pages: 51
Supervisor: Patrick J. C. Ryall