ASSESSEMENT OF INTERNAL STRUCTURE OF PERIGLACIAL LANDFORMS FROM SOUTHERN CARPATHIANS (ROMANIA) USING DC RESISTIVITY TOMOGRAPHY

This study presents the use of DC resistivity tomography for the detection of periglacial landforms structure from Southern Carpathians. Direct-current (DC) resistivity tomography has been applied to six periglacial landforms from the alpine domain of Southern Carpathians for the first time in Romania. Due to important differences in the electrical resistivity of the subsurface materials it was possible to determine the internal structure and the thickness of the periglacial landforms. A rock glacier (Rosiile) from Parang Mountains, two patterned ground sites from Tarcu Mountains, as well as two solifluction phenomena and a scree slope from the central part of Fagaras Mountains were investigated by means of 2D resistivity imaging. The electrical resistivity measurements indicated the presence of sediments cemented by ice and ice lenses in Rosiile rock glacier. The large depth of the active layer and the low content of ice suggest that the permafrost exists in marginal condition and is not in equilibrium with the present climate. A chaotic structural pattern characteristic for the near-surface layer of the patterned ground was interpreted as the result of actual frost heaving. The solifluction lobe and terraces were analyzed comparatively displaying a relatively thin mixture of unconsolidated unfrozen sediments affected by seasonally frozen ground. One scree slope from Vaiuga glacial cirque was investigated in a similar manner revealing a thick mantle of unconsolidated stratified periglacial deposits