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TitleGeomorphology of a late Wisconsin hard-bedded ice stream landsystem, Ontario, Canada revealed by high resolution LiDAR mapping
AuthorBukhari, S S A; Sookhan, S; Eyles, N; Shi, Y; Mulligan, R P M; Paulen, R CORCID logo
SourceGSA 2020 Connects Online - Geological Society of America Annual Meeting; Geological Society of America, Abstracts With Programs vol. 52, no. 6, 2020 p. 1,
Alt SeriesNatural Resources Canada, Contribution Series 20200503
PublisherGeological Society of America
MeetingGSA 2020: Geological Society of America Annual Meeting 2020; October 26-30, 2020
Mediaon-line; digital
File formathtml; pdf
NTS31B; 31C; 31D; 31E; 31F; 31G
AreaSt. Lawrence River
Lat/Long WENS -79.5000 -74.2500 45.6333 43.7500
Subjectssurficial geology/geomorphology; geophysics; Nature and Environment; Science and Technology; glacial history; glaciation; Wisconsinian glacial stage; ice flow; deglaciation; ice retreat; ice margins; geophysical surveys; models; glacial landforms; glacial deposits; glacial features; moraines; hummocks; moraine, de geer; clays; fracturing; freezing ground; glacial grooves; glacial lakes; icebergs; ice scours; Laurentide Ice Sheet; Ontario Ice Stream; Dummer Moraine; Glacial Lake Iroquois; ice streams; moraine ridges; glaciolacustrine sediments; Phanerozoic; Cenozoic; Quaternary
ProgramGEM2: Geo-mapping for Energy and Minerals Mackenzie Corridor, Southern Mackenzie Surficial Mapping
Released2020 10 01
AbstractThe 'age of LiDAR' is revolutionizing the study of the Earth's surface. This paper showcases the enhanced utility of 3-D surface visualization models derived from high-resolution LiDAR data sets over traditionally used 2-D models for the purpose of qualitatively discriminating, classifying and mapping subtle hitherto unmapped glacial landforms left behind by the retreat of a hard-bedded paleo-ice stream (Ontario Ice Stream: OIS) within the Laurentide Ice Sheet in Eastern Ontario, Canada. The hard bed consists of flat-lying Paleozoic limestone plains extending as a broad west-east belt immediately south of the Canadian Shield from Lake Huron to the St. Lawrence River Valley. The largest landform is the Dummer Moraine along the Shield-Paleozoic boundary consisting of undulating hummocky topography composed entirely of clast-supported limestone rubble with large detached bedding plane slabs the result of subglacial hydrofracturing and bed-freezing below a thin retreating ice margin along the northern limit of Paleozoic carbonates. Southward dipping limestone bedding plane surfaces, expressed as extensive bare plains, show swaths of parallel linear grooves cut by fast flowing ice entraining subglacial debris dominated by hard Shield lithologies. The southern and lowest part of the hard bed near Lake Ontario was covered by waters of glacial Lake Iroquois a much larger late glacial precursor to Lake Ontario that drained abruptly at about ~13 cal kyr BP though the Hudson River Valley. Seasonal calving of ice bergs from the retreating ice stream margin standing in glacial Lake Iroquois is recorded by swaths of De Geer moraine ridges composed of bulldozed glaciolacustrine clay and identify an annual ice margin retreat rate between 30 and 100 m. A related but subtle landscape element comprises hundreds of linear to curvilinear ice scours up to 3 km long. This paper highlights the growing importance of geoinformatics techniques in the field of glaciology and the understanding of ice sheet beds and reiterates the need for further research into the application of more advanced computer vision techniques.
Summary(Plain Language Summary, not published)
A presentation at an international conference highlighting the potential and usefulness of high-resolution LiDAR data as a powerful tool for surficial mapping, demonstrated in a region north of Toronto, in southern Ontario.

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