Process Study of Sorted Patterns on Arctic Soils
Patterned ground is ubiquitous in Arctic and alpine areas. To improve understanding of this phenomenon, we developed extensive field instrumentation that has been recording principal soil properties over the past four years. The resulting data constitute the first quantitative year-round records of...
| Main Authors: | , |
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| Format: | Text |
| Language: | English |
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1991
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| Online Access: | http://www.dtic.mil/docs/citations/ADA234089 http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA234089 |
| Summary: | Patterned ground is ubiquitous in Arctic and alpine areas. To improve understanding of this phenomenon, we developed extensive field instrumentation that has been recording principal soil properties over the past four years. The resulting data constitute the first quantitative year-round records of important seasonal process such as freezing, thawing, frost heaving, and settling in the active layer in a sorted circle area. The data provide unprecedented insight into the long-term dynamics of active sorted soil patterns. We have complemented our field research with analytical and numerical studies of sorted pattern formation. Deterministic and stochastic analyses of pattern development in the absence of significant soil deformation reveal strong textural instabilities; stones initially distributed at random through the soil tend to migrate quickly toward domains slightly richer in stones, which eventually leads to the distinct sorting characteristic of diverse forms of patterned ground. Our numerical model of sorted stripe formation successfully simulates stripe development, and sheds considerable light on formative process. We have also developed a novel model to assess buoyancy forces that arise in the thaw process, and may be responsible for the long-term circulatory soil motion documented in sorted circles in Spitsbergen. |
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