Composition and internal structures of a rock glacier on the strandflat of western Spitsbergen, Svalbard

This article presents data on composition and internal structures of a large lobe-shaped rock glacier at Nordenskiöldkysten, western Spitsbergen, based on Ground Penetrating Radar (GPR) and direct current (DC) resistivity tomography measurements. This rock glacier has a more complex surface topography than most rock glaciers in Svalbard and is probably also older. The GPR data indicate a quite chaotic structural pattern, far more complicated than for other investigated rock glaciers in Svalbard. This pattern might be due to the anticipated complex history of the rock glacier, involving glaciation and relative sea level changes. The geophysical results indicate ice-rich conditions, especially below ridges. Overall, the resistivity values are decreasing towards the front of the rock glacier, probably due to dynamic effects. Also, the resistivity results indicate that the active layer is thicker in dumps than below ridges. Considerations of ice content combined with previous velocity measurements indicate that the apparent standstill of the rock glacier is due to the low-gradient situations in which the rock glacier flows onto the strandflat.