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Интеллектуальная Система Тематического Исследования НАукометрических данных |
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Relict debris flows and modern slushflows as agents of severe landscape transformation in the low Subarctic Mountains of NW Russia: magnitudes, affects and ageтезисы доклада
- Автор: Garankina Ekaterina
- Сборник: Abstracts of the EGU Galileo conference: Perturbations of earth surface dynamics caused by extreme events 13-19 October 2019 Nepal
- Тезисы
- Год издания: 2019
- Первая страница: 11
- Последняя страница: 12
- Аннотация: Medium magnitude debris flow phenomena are widespread in the Kola Peninsula Mountains, NW Russia. Most frequently observed types are snowmelt period slushflows and rainfallinduced debris flows. Similar sets of hazardous events are reported for mountainous areas of Scandinavia, Japan and Northern America. Investigation of such events in the Khibiny Mountains over the last 50 years produced a unique dataset of >200 slushflow-affected catchments. However, those surveys concentrated largely on monitoring the consequences of presently observed events while reconstructions of their magnitude and frequency in the past remained beyond the scope of investigations. Large-scale bottom features and piedmont fans found in the majority of small valleys indicate periods of much higher debris flow activity in the past. Reconstructing debris flow activity through the Holocene involved detailed description of associated landforms and deposits using field inspections, satellite and UAV imagery in several mountain valleys of Khibiny and Lovozerskiye Tundry. Grain size analysis and radionuclide fingerprinting of 232Th content in the finer-grained sediments were applied. Limited geochronological framework was established by 14C dating of buried humic and peat layers between superimposed slushflow deposits and was compared to the previously published chronology of slope processes. Available results for >10 studied mountain valleys suggest slushflows and, for some valleys, typical debris flows with lower frequency as a leading mechanism of downstream sediment delivery and valley floor topography formation. Fluvial topography is extremely suppressed or nonexistent under such conditions, as stream channels are unable to rework slushflow deposits and forced to passively adjust. Much lower frequency of extreme events can be estimated as at least twice per millennia. In general, debris flow magnitude has significantly reduced since the recession of the last continental ice cover.
- Добавил в систему: Гаранкина Екатерина Вадимовна
Прикрепленные файлы
| № | Имя | Описание | Имя файла | Размер | Добавлен |
|---|---|---|---|---|---|
| 1. | Полный текст | Nepal2019_abstracts.pdf | 335,3 КБ | 8 января 2020 [EkaterinaGarankina] |