CGRG Bibliography of Canadian Geomorphology
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Author : Brooks, G. R.; and Medioli, B.E.
Date : 2005.
Title : Acoustic profiles and preliminary interpretation of Late Quaternary deposits within basins of the lower French River, Ontario.
Publication : Water, Ice, Land, And Life: The Quaternary Interface. Canadian Quaternary Association 2005 Conference June 5-8, 2005, University of Manitoba, Winnipeg, Manitoba.
Issue : Abstract Volume:
Page(s) : A9.
Abstract
As part of a study investigating the early- to mid-Holocene lake level history of the upper Great Lakes, acoustic profiling of selected basins within the lower French River system, Ontario, was undertaken to: 1) determine if late Pleistocene and Holocene deposits are preserved in the watershed basins, 2) develop an acoustic stratigraphy of the deposits, and 3) identify locations for follow-up coring to investigate the composition and depositional history of the deposits. The profiling was conducted between June 8 and 16, 2004 at seven locations, all situated west of Eighteen Mile Island. Data was collected using a Knudsen 320M™ high-resolution sub-bottom profiler coupled with low (3.5-7.0 kHz) and high (200 kHz) frequency transducers mounted on a 16 ft aluminum boat. Seven acoustic facies are identified in the profiles of the basins. Interpretation of the facies and correlation between basins is preliminary. Facies I is stratigraphically oldest and is composed of weak to well-defined, decimeter-scale bedded deposits that probably represent glaciolacustrine deposits aggraded in glacial Lake Algonquin. Facies II consists of one to three major beds of transparent to weakly internally-bedded deposits. It may have aggraded during a Stanley-Hough low-water stage and could represent a fluvial facies. Facies III generally exhibits moderate to well-defined bedding and is inferred to represent distal glaciolacustrine deposits during a Mattawa high-water stage when the ice front was located well beyond the paleo-shorelines of glacial Lake Algonquin. Facies IV consists of transparent to weakly-bedded deposits. The facies forms the majority of deposits at the sediment-water interface and probably represents Nipissing and post-Nipissing stage gyttja. Facies V is a transparent, channel-infill deposit exhibiting an erosive contact that truncates facies IV and III. Likely consisting of gyttja, the facies is encountered only towards the head of Muskrat Bay and is the stratigraphically youngest deposit in the surveyed basins. The two remaining facies represent bedrock and 'non-bedrock'. The latter is marked by a strong opaque reflector and is hypothesized to delineate the extension of the surface of facies I, or more locally, facies II deposits, where there has been limited penetration of acoustic energy. The acoustic profiling confirms the preservation of late Quaternary deposits within the basins of the lower French River. Based on these results, locations have been identified for coring in spring 2005 to further investigate the composition and chronology of the depositional facies.
Bibliography of Canadian Geomorphology