| Title | Distributions of degraded and intact lithalsas, North Slave region, Northwest Territories |
| Download | Downloads |
| |
| Licence | Please note the adoption of the Open Government Licence - Canada
supersedes any previous licences. |
| Author | Morse, P D ; Rudy,
A C A |
| Source | Geological Survey of Canada, Open File 8869, 2022, 56 pages, https://doi.org/10.4095/329643  Open Access |
| Image |  |
| Year | 2022 |
| Publisher | Natural Resources Canada |
| Document | open file |
| Lang. | English |
| Media | digital; on-line |
| Related | NRCan photo(s) in this
publication |
| Related | This publication is related to the following
publications |
| File format | readme
|
| File format | pdf; rtf; shp (ESRI® ArcExplorer(TM)/ArcReader(TM)); qmd (QGIS®) |
| Province | Northwest Territories |
| NTS | 85J/06; 85J/07; 85J/08; 85J/09; 85J/10; 85J/11; 85J/14; 85J/15; 85J/16 |
| Area | Behchoko; Yellowknife; Great Slave Lake |
| Lat/Long WENS | -115.4000 -114.4667 63.0000 62.4000 |
| Subjects | surficial geology/geomorphology; environmental geology; geophysics; Nature and Environment; Science and Technology; permafrost; ground ice; periglacial features; thermokarst; landforms; climate effects;
terrain sensitivity; remote sensing; satellite imagery; field work; topography; organic deposits; bedrock geology; surface waters; lithalsas; Climate change; Digital elevation data; Inventories; Geographic data; Geographic information systems;
Digitization; Databases; Metadata; glaciofluvial sediments; glaciolacustrine sediments; anthropogenic deposits; Construction; cumulative effects |
| Illustrations | location maps; photographs; geoscientific sketch maps; tables; bar graphs; plots |
| Program | Climate Change
Geoscience Permafrost |
| Released | 2022 02 22 |
| Abstract | The main objective of this report is to provide an inventory of current (intact or degrading) and old (completely degraded) lithalsas in a representative study area of the southern North Slave region
between Behchoko and Yellowknife in the Northwest Territories. A lithalsa is an ice-rich mound of permafrost that causes the soil to settle downward and water to pond if the ice core thaws (thermokarst pond). Lithalsas, widespread in this region, are
therefore very sensitive to thawing. This inventory should help to better understand current and future permafrost conditions, and is based directly on the GSC's Open File 7255, which provides an inventory of many lithalsas in the region, as well as
on the GSC's Open File 8205, which provides an inventory of thermokarst pond development between 1945 and 2005 in the same study area. Using high-resolution satellite images, we completed the inventory of 475 intact lithalsas in the study area. Then,
by combining our field observations of surface geomorphology of degrading lithalsas with recognizable geomorphic patterns in the same satellite imagery, we developed criteria to identify and map them and we developed an inventory of 556 completely
degraded lithalsas. The inventories and databases are prepared for assessment of the relations between elevation, surface geology and distribution of lithalsas, and the trajectory of thermokarst development in the region. The inventories included
with this report can be used directly in a Geographic Information System (GIS). |
| Summary | (Plain Language Summary, not published)
This report presents inventories of 475 intact and 556 degraded lithalsas, southern North Slave region between Behchoko and Yellowknife in the Northwest
Territories. A lithalsa is an ice-rich mound of permafrost that causes the soil to settle downward and water to pond if the ice core thaws, and it is sensitive to thawing. We demonstrate that lithalsas were formerly more widespread at higher
elevations in the study area, but they have degraded, and that lithalsas are predominantly associated with sediments deposited by glacial lakes. |
| GEOSCAN ID | 329643 |
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