Glacial sediments and landforms, southern Victoria Island, Northwest Territories, Canada.
Wollaston Peninsula and most of southern Victoria Island comprise Palaeozoic carbonate lowlands, scarps, and tableland situated between rises and arches of underlying Precambrian sedimentary and igneous rocks. Quaternary sediments are hummocky, thick and ice-cored near escarpments where ice flow res...
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ftunivottawa:oai:ruor.uottawa.ca:10393/7846 2023-05-15T16:22:31+02:00 Glacial sediments and landforms, southern Victoria Island, Northwest Territories, Canada. Sharpe, David Robert. French, H. M. 1992 281 p. application/pdf http://hdl.handle.net/10393/7846 https://doi.org/10.20381/ruor-7002 unknown University of Ottawa (Canada) Source: Dissertation Abstracts International, Volume: 55-03, Section: B, page: 0791. 9780315858503 http://hdl.handle.net/10393/7846 http://dx.doi.org/10.20381/ruor-7002 Geology Thesis 1992 ftunivottawa https://doi.org/10.20381/ruor-7002 2021-01-04T17:04:57Z Wollaston Peninsula and most of southern Victoria Island comprise Palaeozoic carbonate lowlands, scarps, and tableland situated between rises and arches of underlying Precambrian sedimentary and igneous rocks. Quaternary sediments are hummocky, thick and ice-cored near escarpments where ice flow resistance, thrusting and meltwater concentrated glacial debris; thinner, streamlined drift occurs in lowlands. Quaternary sediments are mainly Late Wisconsinan in age. Glacial sediments predominate but surficial raised marine and periglacial sediments are noted. Fluvial modification of the landscape is minor. Many of the spectacular glacial landforms on Wollaston Peninsula are streamlined and indicate formation under thick, warm-based (i.e. free subglacial water) glaciers. A set of distinctive landforms, including ground moraine (with small moraines and marginal channels), hummocky moraine, lateral moraines, and streamlined forms, relates to varying flow conditions within one major glacial advance. Stratified drift within moraines indicates the importance of glaciofluvial processes in addition to ice action. Collectively, these landforms record ice-marginal retreat, marginal stagnation following compressional flow, surging, flooding and regional stagnation during deglaciation. Freeze-on and ice stagnation trapped extensive bodies of drift-rich ice in zones of hummocky moraine. Arborescent networks of narrow eskers record subglacial meltwater drainage beneath major ice lobes and long broad eskers record subaerial deposition by meltwater of mainly supraglacial derivation. Late glacial events are dated relative to the incursion of the sea during deglaciation of northwest areas of Wollaston Peninsula by about 12 000 BP. Active ice-marginal conditions existed just before 10 000 BP, during formation of the large Colville moraines. Ice downwasted in the area causing glacier thinning. Prominent ground-ice features include pingos, thermokarst scars, and debris-flow lobes. Ground ice occurs as massive icy bodies, ice-wedge ice, and buried pingo ice. Based on its setting in hummocky moraine, its stratigraphy, debris content, and isotopic composition, the massive ice is likely buried glacial ice. Landscape modification by thermokarst erosion has produced ubiquitous diamictons similar to till, and landforms similar to glacial forms. Thick ground ice bodies exist only above marine limit and the limits of streamlined landforms because permafrost degradation occurred below these limits. Widespread thaw slumps and large-scale thermal contraction cracks also indicate ice-cored terrain. Thesis glacier* Ice Northwest Territories permafrost Thermokarst Victoria Island victoria island wedge* uO Research (University of Ottawa - uOttawa) Canada Northwest Territories Wollaston ENVELOPE(-60.790,-60.790,-63.668,-63.668) |
institution |
Open Polar |
collection |
uO Research (University of Ottawa - uOttawa) |
op_collection_id |
ftunivottawa |
language |
unknown |
topic |
Geology |
spellingShingle |
Geology Sharpe, David Robert. Glacial sediments and landforms, southern Victoria Island, Northwest Territories, Canada. |
topic_facet |
Geology |
description |
Wollaston Peninsula and most of southern Victoria Island comprise Palaeozoic carbonate lowlands, scarps, and tableland situated between rises and arches of underlying Precambrian sedimentary and igneous rocks. Quaternary sediments are hummocky, thick and ice-cored near escarpments where ice flow resistance, thrusting and meltwater concentrated glacial debris; thinner, streamlined drift occurs in lowlands. Quaternary sediments are mainly Late Wisconsinan in age. Glacial sediments predominate but surficial raised marine and periglacial sediments are noted. Fluvial modification of the landscape is minor. Many of the spectacular glacial landforms on Wollaston Peninsula are streamlined and indicate formation under thick, warm-based (i.e. free subglacial water) glaciers. A set of distinctive landforms, including ground moraine (with small moraines and marginal channels), hummocky moraine, lateral moraines, and streamlined forms, relates to varying flow conditions within one major glacial advance. Stratified drift within moraines indicates the importance of glaciofluvial processes in addition to ice action. Collectively, these landforms record ice-marginal retreat, marginal stagnation following compressional flow, surging, flooding and regional stagnation during deglaciation. Freeze-on and ice stagnation trapped extensive bodies of drift-rich ice in zones of hummocky moraine. Arborescent networks of narrow eskers record subglacial meltwater drainage beneath major ice lobes and long broad eskers record subaerial deposition by meltwater of mainly supraglacial derivation. Late glacial events are dated relative to the incursion of the sea during deglaciation of northwest areas of Wollaston Peninsula by about 12 000 BP. Active ice-marginal conditions existed just before 10 000 BP, during formation of the large Colville moraines. Ice downwasted in the area causing glacier thinning. Prominent ground-ice features include pingos, thermokarst scars, and debris-flow lobes. Ground ice occurs as massive icy bodies, ice-wedge ice, and buried pingo ice. Based on its setting in hummocky moraine, its stratigraphy, debris content, and isotopic composition, the massive ice is likely buried glacial ice. Landscape modification by thermokarst erosion has produced ubiquitous diamictons similar to till, and landforms similar to glacial forms. Thick ground ice bodies exist only above marine limit and the limits of streamlined landforms because permafrost degradation occurred below these limits. Widespread thaw slumps and large-scale thermal contraction cracks also indicate ice-cored terrain. |
author2 |
French, H. M. |
format |
Thesis |
author |
Sharpe, David Robert. |
author_facet |
Sharpe, David Robert. |
author_sort |
Sharpe, David Robert. |
title |
Glacial sediments and landforms, southern Victoria Island, Northwest Territories, Canada. |
title_short |
Glacial sediments and landforms, southern Victoria Island, Northwest Territories, Canada. |
title_full |
Glacial sediments and landforms, southern Victoria Island, Northwest Territories, Canada. |
title_fullStr |
Glacial sediments and landforms, southern Victoria Island, Northwest Territories, Canada. |
title_full_unstemmed |
Glacial sediments and landforms, southern Victoria Island, Northwest Territories, Canada. |
title_sort |
glacial sediments and landforms, southern victoria island, northwest territories, canada. |
publisher |
University of Ottawa (Canada) |
publishDate |
1992 |
url |
http://hdl.handle.net/10393/7846 https://doi.org/10.20381/ruor-7002 |
long_lat |
ENVELOPE(-60.790,-60.790,-63.668,-63.668) |
geographic |
Canada Northwest Territories Wollaston |
geographic_facet |
Canada Northwest Territories Wollaston |
genre |
glacier* Ice Northwest Territories permafrost Thermokarst Victoria Island victoria island wedge* |
genre_facet |
glacier* Ice Northwest Territories permafrost Thermokarst Victoria Island victoria island wedge* |
op_relation |
Source: Dissertation Abstracts International, Volume: 55-03, Section: B, page: 0791. 9780315858503 http://hdl.handle.net/10393/7846 http://dx.doi.org/10.20381/ruor-7002 |
op_doi |
https://doi.org/10.20381/ruor-7002 |
_version_ |
1766010492631908352 |