Geological and Geomorphological Indicators of the Surge Behaviour of the Aldegonda Glacier (West Spitsbergen) in the Little Ice AgeстатьяИсследовательская статья
Статья опубликована в журнале из списка Web of Science и/или Scopus
Аннотация:The results of investigations of the landforms and sediments in the marginal zone of the Aldegonda Glacier are presented. As a result of the geomorphological analysis of the Aldegonda Glacier proglacial zone, geological and geomorphological indicators of its surge behaviour in the Little Ice Age (700–100 yr BP) were proposed on the basis of the features and velocities of ice propagation and degradation during the phases of advance and retreat. These features were reconstructed from the configuration of lateral moraines and from the location of terminal moraines (submarine and terrestrial) and according to the historical data. Two different age generations of ridges of the left lateral moraine were distinguished. The young lateral moraine (dated to the Little Ice Age) is oriented parallel to the axis of glacier movement, and the ancient one (older than 12 cal ka BP) is at an angle to it. The difference in orientation is caused by a different velocity of the glacier movement that was slower before 12 ka BP and more rapid at 700–100 yr BP. Different mechanisms were established for the formation of two terminal moraines: pushing (below sea level) and dumping (on land). The first one was interpreted as a result of the rapid glacier advance, and the second one, because of the stabilization of the glacier front during the areal degradation of the terrestrial part of the glacier’s advanced tongue, followed by its rapid retreat, as was established by the historical information. Landform-indicators, such as fluted moraine and crevasse-fill ridges, were suggested as additional geomorphological features of the surge behaviour.
