Climate Studies DISTRIBUTION OF PATTERNED GROUND AND SURFICIAL DEPOSITS ON

• Main Authors: Andrew M. Lorrey, Glacier Suwace, In Mullins, Valley, M. Lorrey
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 2002
• Subjects: Antarctic; Beacon Valley; East Antarctic Ice Sheet; Antarc*; Ice Sheet
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.578.946; http://www.library.umaine.edu/theses/pdf/LorreyAM2002.pdf

East Antarctic Ice Sheet (EAIS). The surficial material on the floor of Beacon Valley is segmented into large polygonal landforms separated by trenches. Buried beneath the polygons and surficial material is massive ground ice. One hypothesis is that the buried ice in upper Beacon Valley is glacier ice originating from local debris-covered glaciers. The networks of polygons and trenches forn ~ as the buried ice undergoes thermal contraction and sublimation. Contraction cracks that penetrate the surficial material and buried ice in Beacon Valley contain Late Miocene age volcanic ashes. The ashes post-date the buried ice. The preservation of such old ice implies a continuous extreme polar condition in Beacon Valley since late Miocene time. An alternative explanation is that the buried ice in Beacon Valley is modem ground ice that formed from percolation of melted, wind-blown snow that subsequently froze within the sediment mantle. Polygonal landforms would result from the seasonal freeze-thaw of the modem ground ice and surficial material. Continual freeze-thaw action, or cryoturbation, would create a mass of coalesced, modern ice lenses covered with older sediment. The buried ice in this case could be young, and hence could not be