Soil and permafrost in the Ross Sea region of Antarctica: stable or dynamic?
Soils in the Ross Sea Region of Antarctica generally comprise a surface desert pavement and a seasonally thawed active layer over permafrost. Most soils are formed on regolith such as glacial till or colluvium. Mean annual air temperatures range from -18°C to -24°C with low precipitation. The active...
| Published in: | Cuadernos de Investigación Geográfica |
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| Main Authors: | , |
| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
Universidad de La Rioja
2016
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| Subjects: | |
| Online Access: | https://publicaciones.unirioja.es/ojs/index.php/cig/article/view/2923 https://doi.org/10.18172/cig.2923 |
| Summary: | Soils in the Ross Sea Region of Antarctica generally comprise a surface desert pavement and a seasonally thawed active layer over permafrost. Most soils are formed on regolith such as glacial till or colluvium. Mean annual air temperatures range from -18°C to -24°C with low precipitation. The active layer ranges in depth from minimal in higher altitude, colder sites, to near 1 m deep at warmer coastal sites in the northern part of the region. Underlying permafrost may be ice-cemented, or dry with no ice cement. In some areas ice-cored moraine occurs where there is a large body of ice within the subsoil permafrost. Two examples of active gully/fan -forming events, one at Cape Evans and one at Lake Vanda are described. At the Cape Evans event water from a small lake thawed and came into contact with the ice in the underlying patterned ground ice-wedge causing the ice-wedge to melt and extensive gully erosion to occur. A fan-building event near Lake Vanda in the Wright Valley resulted in erosive and depositional features covering a horizontal distance of about 3 km and an altitudinal range of about 1400 m. Such occasional events, can be attributed to warmer than average summers, and were first described in the Ross Sea Region in the 1970s. The Cape Evans and Lake Vanda events are examples of active, rapid, landscape processes and show that landscapes are not as static as is often assumed. Los suelos en la región del Mar de Ross de la Antártida comprenden generalmente un pavimento superficial desértico y un nivel activo que se descongela estacionalmente por encima del permafrost. La mayoría de los suelos están formados sobre un regolito del tipo till glaciar o coluvión. Las temperaturas medias anuales oscilan entre -18ºC y -24ºC, con una escasa precipitación. El nivel activo oscila desde valores mínimos en áreas de elevada altitud y sitios fríos, hasta 1 m de profundidad en sitios costeros más templados en la parte norte de la región. El permafrost subyacente puede estar cementado por el hielo, o seco, sin cemento ... |
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