Geophysical approach to the study of a periglacial blockfield in a mountain area (Ztracené kameny, Eastern Sudetes, Czech Republic)

Fluctuation of climatic events in Central Europe with oceanic and continental influences intensified during the Pleistocene, especially above the timberline, enabled the analysis of this record on the ridge and slopes of the Ztracené kameny massif (1245 m a.s.l.), Czech Republic. Seismic refraction tomography (SRT) and electrical resistivity tomography (ERT) are geophysical methods that, that allow the comprehensive recognition of shallow geological structures in a strongly folded area of the High Jesenik Mountains. Geophysical surveys were performed to determine structure and thickness of the quartzite blockfield and its boundary with consolidated rock. The measured resistivity values were compared with the seismic wave velocities. The resistivity values of the block cover show significant differences according to its morphology, slope orientation and altitude. The data analysis indicates an occurrence of remnants of Pleistocene permafrost. The subnival traces within the blockfield demonstrate the intensity of past slope processes and the role of frost weathering even during the Holocene.