At the end of the Ra period, approximately 10,600 years ago, the icefront retreated mostly by calving with intermittent stops through the long and narrow Numedalfjorden. Average recession rates lie between 90-100 m per year. Detailed mapping of Glacial and Postglacial sediments, combined with radiocarbon and geophysical data, allowed reconstruction of Late Glacial and Holocene development, dating of glaciofluvial and river valley terraces, and calculation of average sedimentation rate during Preboreal time in a deep ice-eroded basin.