PARAGLACIAL SLOPE ADJUSTMENT AND RESEDIMENTATION FOLLOWING RECENT GLACIER RETREAT, FABERGSTOLSDALEN, NORWAY

Withdrawal of glacier ice from upper Fabergstolsdalen after A.D. 1930 has exposed steep drift-covered slopes on the north side of the valley . Since 1943 these have experienced radical transformation into gullie d badlands, with reworked sediments being redeposited on the valley fl oor as coalescing debris cones. Gully erosion has exposed wide areas o f bedrock, and has extended upslope outside the limit of Little Ice Ag e (18th century A.D.) glacier advance. Over much of the gullied area, ground surface lowering has been 2.5 to 4.7 m, representing a minimum erosion rate of 50 to 100 mm yr-1, and average gradients have been red uced by 5-degrees. The principal agent of sediment reworking is debris flow activity, in part triggered by rapid snowmelt at gully heads. Th e eroded sediments consist of Little Ice Age till overlying Preboreal (ca. 9 ka) paraglacial deposits. and a cycle of alternating glacial an d paraglacial sedimentation is inferred, the former accompanying glaci er advance. the latter following glacier retreat. Paraglacial debris f low deposits inherit many of the sedimentological characteristics of t he parent till, but may be distinguished on structural grounds and by preferred clast orientation. The rapidity of landscape change in upper Fabergstolsdalen implies that extensive paraglacial modification of r ecently deglaciated terrain may occur over a timescale of decades rath er than centuries.