The Rogowiec Landslide Complex (Central Sudetes, SW Poland) : a case of a collapsed mountain

The paper focuses on a large relict landslide complex in the northeastern part of the Kamienne Mts. (Sudetes, SW Poland) developed on Carboniferous and Permian volcanic and clastic sedimentary rocks. Whilst the presence of mass movements around Mt. Rogowiec has long been known, no attempts have yet been made to offer a comprehensive analysis. This study is based on recognition of geomorphic features from LiDAR-derived DTM, geomorphometric analysis, field geomorphological mapping, joint measurements at representative exposures, and electrical resistivity tomography. The total area affected by gravitational slope deformation exceeds 40 ha and consists of a few smaller units that show distinctive patterns of displacement. The eastern slopes of the Mt. Rogowiec ridge have been reshaped by large slides involving rigid blocks of trachyandesite in the upper part and deformed sedimentary successions in the middle and lower part. The central part of the area has experienced lateral spreading which resulted in complete disintegration of the volcanic cap. Fresh-looking ridge-top trenches indicate that this process is ongoing. Subsequent movements included flows into pre-existing valleys and rock wall collapses to produce spectacular block streams. The scale and variety of deformation structures at Mt. Rogowiec make this locality unique in the Sudetes.