A multibeam bathymetric survey of Bay of Islands, Newfoundland: new evidence of late-glacial and Holocene geological processes

• Published in: Atlantic Geology
• Main Authors: Shaw, John, Batterson, Martin, Christian, Harold, Courtney, Robert C.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Atlantic Geoscience Society 2000
• Subjects: Deer Lake; Lac Deer; Tait; Newfoundland; Terre-Neuve
• Online Access: https://journals.lib.unb.ca/index.php/ag/article/view/2017

Multibeam bathymetric imagery of Ray of Islands, Newfoundland, is interpreted within the context of late-glacial and post-glacial processes- West of Humber Arm, the fiord floor is irregular and deep. Humber Arm has steep sidewalls and a flat floor. It contains glaciomarine mud. capped by a layer of red mud probably derived from the Deer Lake Basin, which was connected to the ocean ca. 12.2 ka. In the early postglacial period, sediments on the fiord sidewalls slid into deep water, forming erosional channels. Depositional lobes, stacked in many areas, overlie glaciomarine sediments in deep water. The glaciomarine and submarine slide sediments are overlain by postglacial mud that is imprinted by elongate, ovoid, and circular fluid-escape trenches, and sedimentary furrows. The natural morphology of the fiord has been modified by anthropogenic activity at Comer Brook. Effects include an apron of bark offshore from the paper mill, dredge spoil, and a sunken vessel at the mouth of Humber River. Large submarine slides, probably triggered by wharf construction at Seal Head, formed deep channels on the fiord sidewalls and overlapping depositional lobes on the fiord floor. They are morphologically similar to the lateglacial slide failures in the fund. RÉSUMÉ Les images bathymétriques multifaisceaux de Bay of Islands, Terre-Neuve, sont interprétées dans le contexte des processus tardiglaciaires et post-glaciaires. À I'ouest de Humber Arm. Ie fond du l’jord est irrégulier et profond. Humber Arm est doté de parois abruptes et d'un fond plat. Il renferme de la boue glaciomarine recouverte d'une couche de boue rouge provenant probablemenl du bassin du lac Deer, qui était relié à l'océan il y a environ 12.2 millies d'années avant nos jours. Au début de la période post-glaciaire, Ies sediments sur Ies parois du l’jord ont glissé a l’intérieur de I'eau profonde en formant des ...