Formy i osady glacjalne w dolinie Małej Płoszanki (Karpaty Wschodnie, Ukraina)

Glacial landforms and sediments in the Mala Ploshanka valley (Eastern Carpathians, Ukraine)

Summary: The Borzhava range (1682 m) is a prominent mountain range within the NW part of the Ukrainian Carpathians, where the traces of Pleistocene glaciation are poorly recognised and which is still lacking detailed geomorphological case studies. In this paper, we present the result of detailed geomorphological mapping, remote sensing data analysis and sedimentological analysis, which provide first evidence of glacial activity in the Borzhava range (1679 m). Detailed geomorphological studies were conducted in the middle and upper part of the Mala Ploshanka valley (NE part of the range) where the glacial landforms and sediments are particularly well-preserved. According to obtained results, the maximal ice extent (ca. 1 km long) documented by preserved frontal moraines reached an elevation of 1075 m a.s.l. Amphitheatre-shaped and relatively deep Yama glacial cirque was cut out in the headwaters of the Mala Ploshanka valley. Its vast floor lies at an considerably low altitude (1250?-?1300 m) in comparison with the surrounding mountain ranges. Our data support a cirque-valley glaciation on the NE slopes of Borzhava range during the last glaciation. Results of clast-shape (C??0) and roundness (RA) analysis show clearly distinct characteristics between the controlled samples of slope environment (slope covers, alluvial sediments) and moraine deposits in the study area. Most of the sandstone clasts within the moraine sediments in the terminal and cirque part of the former glacier system were actively transported (subglacially modified), however, some samples in the middle of the studied valley indicate also passively-transported conditions.

Słowa kluczowe: cyrki glacjalne, osady morenowe, wskaźniki C?40 i RA, Połonina Borżawa, Karpaty Wschodnie, Ukraina

Słowa kluczowe (w języku angielskim): glacial cirques, moraine sediments, C?40 and RA indices, Borzhava range, Eastern Carpathians, Ukraine

Fiedeń Ł., Anielska K., Listwan-Franczak K., Franczak P. (red.), 2018, Współczesne problemy i kierunki badawcze w geografii. tom 6, IGiGP UJ, Kraków, s. 99-126.

Instytut Geografii i Gospodarki Przestrzennej UJ

ISBN 978-83-64089-45-9

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