Mapping of an ancient 'dead-ice' sink using electromagnetic reflection method (EMR, GPR).

Electromagnetic reflection method (EMR, ground penetrating radar, GPR) has been used to delineate the groundwater table as well as to map shallow subsurface structures in selected areas in northern Germany. At a wooded area, one site revealed complex subsurface structures, which had no surface expression. A distinct sandy-filled, trough-shaped structure totally encased in silts was mapped. This structure is interpreted as 'dead-ice' sink, which shaped at the end of the late-glacial period due to melting of dead ice block and later filled with sediments.