期刊
GEOMORPHOLOGY
卷 204, 期 -, 页码 302-313出版社
ELSEVIER SCIENCE BV
DOI: 10.1016/j.geomorph.2013.08.014
关键词
Discontinuous permafrost; Great Slave Lowland; Lithalsa; Segregated ground ice
资金
- Climate Change Geoscience Program of Natural Resources Canada
- Northern Scientific Training Program, Aboriginal Affairs and Northern Development Canada
- Polar Continental Shelf Project, Natural Resources Canada
Lithalsas are permafrost mounds formed by ice segregation in mineral-rich soil that occur within the zone of discontinuous permafrost. Nearly 1800 lithalsas were mapped using archival aerial photographs within the Great Slave Lowland, Northwest Territories, Canada. These are up to 8 m high and several hundred meters in length and width. One lithalsa, examined by electrical resistivity and boreholes, rises 4 to 6 m above an adjacent peatland, shows clear evidence of ice-segregation at depth and ground heave of between 2.5 and 4.0 m, and is estimated to have formed within the past 700 years. Regionally, lithalsas are typically located adjacent to ponds and streams with mature forms vegetated by deciduous (birch) forest or mixed (birch and spruce) forest with a herb-shrub understory and include circular, crescentic and linear forms. They are abundant within the Lowland region, which contains widespread glaciolacustrine, lacustrine and alluvial fine-grained sediments. The lithalsas are most common within the first few tens of meters above the present level of Great Slave Lake, indicating that many are late Holocene, and some less than 1000 years, in age. A comparison with lithalsas in contemporary environments reveals that comparatively warm but extensive discontinuous permafrost, fine-grained sediments (alluvial, lacustrine, marine or glaciomarine), and available groundwater supply provide the climatic and hydro-geological parameters for the development of lithalsas in permafrost terrain. The identification of lithalsas in this region is important given their sensitivity to climate change and potential hazards to northern infrastructure upon thawing. Crown Copyright (C) 2013 Published by Elsevier B.V. All rights reserved.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据