Structural control of mass movements on slopes formed of magmatic and metamorphic rocks: the case study of Wielisławka Mt. (SW Poland, Sudetes Mts.)

Abstract

We indicate the structural controls on, and provide an evolutionary model of, mass movements which developed on the slopes of a rhyolitic lava dome built of massive, sub-intrusive Permian rhyolites and its low-grade metamorphic cover, comprising Ordovician and Silurian sericite schists and metacherts (greenschist facies). The phenomena studied occur on the low-altitude, dome-like Wielisławka Mt. (370 m a.s.l.) in the Western Sudetes, SW Poland. A multidisciplinary approach involving geological and geomorphological fieldwork, LiDAR-based geomorphometric analyses, as well as analyses based on data obtained from terrestrial laser scanning (TLS), performed within old adits and shafts in the landslide area, have allowed determination of the origin and recent extent of the landslide phenomena. The geometry and development of the slip surface are closely linked with measured, existing discontinuities within the massif. As they enable observation of the initial stages of mass movement in the excavations within the cover rocks of the rhyolitic massif, the old adits and shafts are unique objects for the observation and reconstruction of landslide processes.