Characteristics and evolution of the rock glacier near Musala Peak (Rila Mountains, Bulgaria)

The article presents results from the first detailed study of the rock glacier near Musala Peak in the Rila Mountains (Bulgaria), performed in 2016–2017. Situated at 2600–2670 m a.s.l. the rock glacier is among the highest in Bulgarian mountains. It is made of granitic blocks derived from the northern slope of Musala Peak (2925 m a.s.l.). This paper presents a hypothesis on the formation and development of the rock glacier, based on detailed geomorphological mapping and rock weathering rate tests. First results from Schmidt hammer testing of rock glaciers in Bulgaria are presented and discussed. The values obtained from 782 tests show increase in rock strength from the lower to the upper part of the block accumulation, which indicates their sequential deposition over time. The rock glacier was formed in the period after the retreat of Pleistocene glaciers and most likely before the Atlantic optimum of the Holocene. Geomorphic evidence indicates at least two stages of rock glacier development. Recently it has been considered relict. However, some activity during the Little Ice Age, and even at present, is not completely excluded.

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Opracowanie rekordu w ramach umowy 509/P-DUN/2018 ze środków MNiSWprzeznaczonych na działalność upowszechniającą naukę (2019).