Late Wisconsinan glacial history of Placentia Bay, Newfoundland, as interpreted from seabed geomorphology and stratigraphy
Thesis (M.Sc.)--Memorial University of Newfoundland, 2008. Geography Includes bibliographical references (leaves 115-122). This thesis reconstructs the glacial history of Placentia Bay, Newfoundland through the integration of seabed data and existing terrestrial records. Multibeam sonar data, augmen...
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ftmemorialunivdc:oai:collections.mun.ca:theses4/66934 2023-05-15T16:22:29+02:00 Late Wisconsinan glacial history of Placentia Bay, Newfoundland, as interpreted from seabed geomorphology and stratigraphy Brushett, Denise Michelle, 1975- Memorial University of Newfoundland. Dept. of Geography Canada--Newfoundland and Labrador--Placentia Bay Pleistocene 2008 xii, 144 leaves : ill., maps (some col.) Image/jpeg; Application/pdf http://collections.mun.ca/cdm/ref/collection/theses4/id/66934 Eng eng Electronic Theses and Dissertations (16.93 MB) -- http://collections.mun.ca/PDFs/theses/Brushett_Denise.pdf a2523368 http://collections.mun.ca/cdm/ref/collection/theses4/id/66934 The author retains copyright ownership and moral rights in this thesis. Neither the thesis nor substantial extracts from it may be printed or otherwise reproduced without the author's permission. Paper copy kept in the Centre for Newfoundland Studies, Memorial University Libraries Geology Stratigraphic--Pleistocene Glacial landforms--Newfoundland and Labrador--Placentia Bay--History Glaciers--Newfoundland and Labrador--Placentia Bay--History Text Electronic thesis or dissertation 2008 ftmemorialunivdc 2015-08-06T19:22:05Z Thesis (M.Sc.)--Memorial University of Newfoundland, 2008. Geography Includes bibliographical references (leaves 115-122). This thesis reconstructs the glacial history of Placentia Bay, Newfoundland through the integration of seabed data and existing terrestrial records. Multibeam sonar data, augmented by seismic and coring data revealed a range of flow-parallel and flow-transverse glacial landforms on the Placentia Bay seabed. Flow-parallel landforms include drumlins, flutes, megaflutes and crag-and-tails. These landforms show a general trend of convergent flow, interpreted to represent fast-flowing ice converging into an ice stream down the axis of Placentia Bay. Flow-parallel landforms and striations from the surrounding land areas demonstrate that the convergent flow can be traced up-ice to regional ice dispersal centres. Flow-transverse landforms include De Geer moraines and grounding-line moraines. De Geer moraines occur in several fields throughout the bay marking the intermittent retreat of grounded ice up the bay. Radiocarbon ages from glaciomarine silt suggest that ice became ungrounded and glaciomarine sedimentation started ca. 16.1 cal ka BP and ended after 12.0 cal ka BP. This glacial landsystem is consistent with a conceptual model showing Late Wisconsinan ice advance to shelf edges with rapid calving retreat along deepwater channels and slower retreat of ice margins grounded in shallow water. The integrated approach used in this study 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 which may reflect deglacial scenarios in other bays in Newfoundland and elsewhere. Thesis glacier* Ice Sheet Newfoundland studies University of Newfoundland Memorial University of Newfoundland: Digital Archives Initiative (DAI) Newfoundland Canada |
institution |
Open Polar |
collection |
Memorial University of Newfoundland: Digital Archives Initiative (DAI) |
op_collection_id |
ftmemorialunivdc |
language |
English |
topic |
Geology Stratigraphic--Pleistocene Glacial landforms--Newfoundland and Labrador--Placentia Bay--History Glaciers--Newfoundland and Labrador--Placentia Bay--History |
spellingShingle |
Geology Stratigraphic--Pleistocene Glacial landforms--Newfoundland and Labrador--Placentia Bay--History Glaciers--Newfoundland and Labrador--Placentia Bay--History Brushett, Denise Michelle, 1975- Late Wisconsinan glacial history of Placentia Bay, Newfoundland, as interpreted from seabed geomorphology and stratigraphy |
topic_facet |
Geology Stratigraphic--Pleistocene Glacial landforms--Newfoundland and Labrador--Placentia Bay--History Glaciers--Newfoundland and Labrador--Placentia Bay--History |
description |
Thesis (M.Sc.)--Memorial University of Newfoundland, 2008. Geography Includes bibliographical references (leaves 115-122). This thesis reconstructs the glacial history of Placentia Bay, Newfoundland through the integration of seabed data and existing terrestrial records. Multibeam sonar data, augmented by seismic and coring data revealed a range of flow-parallel and flow-transverse glacial landforms on the Placentia Bay seabed. Flow-parallel landforms include drumlins, flutes, megaflutes and crag-and-tails. These landforms show a general trend of convergent flow, interpreted to represent fast-flowing ice converging into an ice stream down the axis of Placentia Bay. Flow-parallel landforms and striations from the surrounding land areas demonstrate that the convergent flow can be traced up-ice to regional ice dispersal centres. Flow-transverse landforms include De Geer moraines and grounding-line moraines. De Geer moraines occur in several fields throughout the bay marking the intermittent retreat of grounded ice up the bay. Radiocarbon ages from glaciomarine silt suggest that ice became ungrounded and glaciomarine sedimentation started ca. 16.1 cal ka BP and ended after 12.0 cal ka BP. This glacial landsystem is consistent with a conceptual model showing Late Wisconsinan ice advance to shelf edges with rapid calving retreat along deepwater channels and slower retreat of ice margins grounded in shallow water. The integrated approach used in this study 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 which may reflect deglacial scenarios in other bays in Newfoundland and elsewhere. |
author2 |
Memorial University of Newfoundland. Dept. of Geography |
format |
Thesis |
author |
Brushett, Denise Michelle, 1975- |
author_facet |
Brushett, Denise Michelle, 1975- |
author_sort |
Brushett, Denise Michelle, 1975- |
title |
Late Wisconsinan glacial history of Placentia Bay, Newfoundland, as interpreted from seabed geomorphology and stratigraphy |
title_short |
Late Wisconsinan glacial history of Placentia Bay, Newfoundland, as interpreted from seabed geomorphology and stratigraphy |
title_full |
Late Wisconsinan glacial history of Placentia Bay, Newfoundland, as interpreted from seabed geomorphology and stratigraphy |
title_fullStr |
Late Wisconsinan glacial history of Placentia Bay, Newfoundland, as interpreted from seabed geomorphology and stratigraphy |
title_full_unstemmed |
Late Wisconsinan glacial history of Placentia Bay, Newfoundland, as interpreted from seabed geomorphology and stratigraphy |
title_sort |
late wisconsinan glacial history of placentia bay, newfoundland, as interpreted from seabed geomorphology and stratigraphy |
publishDate |
2008 |
url |
http://collections.mun.ca/cdm/ref/collection/theses4/id/66934 |
op_coverage |
Canada--Newfoundland and Labrador--Placentia Bay Pleistocene |
geographic |
Newfoundland Canada |
geographic_facet |
Newfoundland Canada |
genre |
glacier* Ice Sheet Newfoundland studies University of Newfoundland |
genre_facet |
glacier* Ice Sheet Newfoundland studies University of Newfoundland |
op_source |
Paper copy kept in the Centre for Newfoundland Studies, Memorial University Libraries |
op_relation |
Electronic Theses and Dissertations (16.93 MB) -- http://collections.mun.ca/PDFs/theses/Brushett_Denise.pdf a2523368 http://collections.mun.ca/cdm/ref/collection/theses4/id/66934 |
op_rights |
The author retains copyright ownership and moral rights in this thesis. Neither the thesis nor substantial extracts from it may be printed or otherwise reproduced without the author's permission. |
_version_ |
1766010461542678528 |