CGRG Bibliography of Canadian Geomorphology
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Author : Brushett, D.; Bell, T.; Shaw, J.; and Batterson, M.J.
Date : 2007.
Title : Ice flow history of Placentia Bay, Newfoundland as interpreted from seabed mapping.
Publication : CANQUA Ottawa 2007. Canadian Quaternary Association Conference, June 4-8, 2007. Carleton University, Ottawa, Ontario, Canada.
Issue :
Page(s) :
Abstract
This paper details the ice-flow history of Placentia Bay, Newfoundland as interpreted from both onshore and offshore glacial records using recently generated seabed and landscape imagery. Recent technological advances in both terrestrial (Shuttle Radar Topography Mission (SRTM)) and marine (multibeam bathymetric sonar) mapping have generated landscape and seabed imagery that permit a broader interpretation of glacial geomorphology and palaeo ice dynamics. Multibeam sonar imagery of Placenta Bay shows a range of flow-parallel and flow-transverse glacial landforms. Flow-parallel landforms identified include drumlins, flutes, megaflutes, mega-lineations, and crag-and-tail landforms. These landforms show a general trend of convergent ice flow, interpreted to represent fast-flowing ice (an ice stream) down the axis of Placentia Bay. Drumlins and fluted terrain onshore demonstrate that the convergent ice flow can be traced up-ice to regional dispersal centres. Flow-transverse landforms interpreted as DeGeer moraines occur in several fields throughout the bay marking the intermittent retreat of a tidewater margin that became grounded in shallow water. Ice-flow mapping of Placentia Bay also demonstrated that the largely depositional record preserved on the seabed is incomplete, with the apparent absence of a strong westward flow onto the Burin Peninsula. The mostly erosional ice-flow record on land also appears incomplete because there is no evidence, to date, for a northeastward-southwestward ice flow that is recorded by a fluting field on the seabed of southwestern Placentia Bay. The integration of onshore and offshore glacial records in Newfoundland represents an important development in mapping palaeo ice flows and the understanding of ice-sheet behaviour during the transition from largely marine-based to land-based glacial conditions.
Bibliography of Canadian Geomorphology