Vestnik MGTU (Mar 2018)
On the influence of latitudinal climatic zonation on the degradation of the Late Valday (Late Visla) glaciation with the example of marginal formations of the territories of Finland and Karelian-Kola region
Abstract
It is established that the Keyva-2 ridge developed in the eastern Kola Peninsula is not a marginal formation of the Ponoy ice shield. It was mainly formed between the Kola and Belomorian glacial lobes of the late Valdai glaciation spread eastward. Using the example of the last cover glaciation, it has been shown that the latitudinal climatic zonation influenced the deglaciation process of the territories of Finland and the Karelian-Kola region. This influence manifested itself as follows: in the Kola region, where the Kola and Belomorian lobes were located near east-west, the areal deglaciation took place. On the surface of both lobes, about the same amount of solar energy came, resulting in a decrease of the ice thickness over the entire area, followed by separation of vast peripheral massifs from the active ice massif. In other words, here an areal deglaciation occurred. The areal deglaciation also manifested itself irrespective of climatic zonation during the final interstadial-stadial climatic cycle due to the low thickness of the ice cover and it spread as far as the south of Finland. However, climate exerted some influence during this period, too: the glacier in the Late Dryas in the south only overlapped Alleröd bulk ridges by moraine, deformed them northward and, having moved further to the east, created a ridge of predominantly pressure moraines. In Karelia, where the glacial lobes stretched from the northwest to the southeast, the distal (frontal) part of the blades received significantly more solar energy than the proximal part. Therefore, a frontal deglaciation with a free movement of the glacier edge during the periods of interstadial warming and cooling occurred with the formation of stripes of marginal pressure-bulked (mainly pressure) formations during cooling.
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