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The chronology of Cryogenic Slope Processes in the Subarcticтезисы доклада
- Авторы: Romanenko Fedor, Garankina Ekaterina
- Сборник: International Conference «Permafrost in XXI century: basic and applied researches» Pushchino, Moscow region, Russia, September 27 – October 1, 2015. Program and Conference materials
- Том: 1
- Тезисы
- Год издания: 2015
- Место издания: Pushchino
- Первая страница: 60
- Последняя страница: 62
- Аннотация: It’s been more than 100 years since the Swedish geologist and archeologist J.G. Andersson (1874-1960) suggested the term “solifluction” for the description of “the slow flowing from higher to lower ground of masses of waste saturated with water (this may come from snow-melting or rain)” (Andersson, 1906, p.96), which he discovered during his expeditions to the Medvegiy Island to the south of Spitzbergen in 1898 and to the Falkland Islands in 1902. Since then in many regions of Earth there has been established the morphology of the solifluction slopes, mechanisms, distribution and modern intensity of the solifluction processes, the peculiarities of forming of solifluction sediments. Nowadays the reconstruction of the changes of intensity of the solifluction and other kinds of slope sediments in time is considered not only a fundamental, but also a practical aim, especially considering present climate changes. A powerful weapon in solving this problem became the method of radiocarbon dating of the slope sediments. Studies like this are held in Canadian Cordillera, 61 Finnish Lapland, Spanish Sierra Nevada and Alps. For example, in Alps there has been detected 5–7 epochs of solifluction’s activation (Oliva et all., 2009). In European Subarctic Mountains dating of slope processes was begun in 1980s in Khibiny Mountains, where T.V. Vaschalova (1987) by radiocarbon dating of buried organic remains in avalanche cones determined three periods of decreases of the avalanche activity: 4100–3800 years BC, IV century BC- III century AD, 790-1560 AD, and also the period of its increasing during Little Ice Age (LIA) in XVII-XIX century. Recently in the Central Yamal there have been revealed 7 periods of cryogenic landslides’ activation, in 250 year BC and in 210, 640, 1000, 1300, 1700, 1989 years AD, which coincide with mild summer (Leibman, Kizyakov, 2007). In 2010-2014 we held field works under different lithological and physical geographical conditions in Khibiny Mountains, on absolute heights of 500-600 meters in uppers of Medvegiy stream on 67o44,38 N, 33o16,94 O, and in Uksporriok valley on 67o39,37 N, 33o49,98 O, also on the slope of Barkov mountain in near Polar Ural region on 65o11,77 N, 60o20,26 O, on the height 940–980 meters. The dating of buried grassy turf allowed to determine several periods of activation of slope movement on Khibiny mountains in 1990–1779 years BC, 1600 years BC – 400 years AD, 540–990, 1270–1480 years AD. Nowadays the signs of active ground movements are rare. Part of dated terraces is being overgrown intensively, on the others there are no ground covering, as it is being harmed by cryogenic and aeolian processes. The soils during periods 1480–1670 was being formed during the period of a clear cooling (LIA), when little glaciers appeared in Khibiny again and are preserved till nowadays. On the Polar Ural the solifluction is happening with a considerable velocity, because the soils with more than 150 years of age has already deformed it. The works are supported by the Russian Scientific Fund (project № 14-37-00038)
- Добавил в систему: Романенко Фёдор Александрович