Niveo‐aeolian sedimentation and resulting sedimentary structures; søndre strømfjord area, Western Greenland

Winter observations were carried out on aeolian sand sheets in Western Greenland, in order to obtain insight into the occurrence and influence of niveo‐aeolian sedimentation in modern cold‐climate sand‐sheet environments. The alternating or simultaneous aeolian transportation of snow and sand appears to form an important factor in the sedimentation. Niveo‐aeolian beds develop annually and are deposited during a period when the snow cover is thin. They are covered by clean snow when sand transport is impeded by ample snow or insufficient wind velocity. The nature and significance of denivation features in the sedimentological record are equally poorly understood. In order to study these snow‐related structures, the winter observations are compared with sections trenched in summer when no snow was left. After desiccation of the surface in summer, the sediments deriving from the niveo‐aeolian beds on planar and low‐angle inclined surfaces are likely to be redistributed by wind action. However, on slip faces denivation structures are frequently preserved as deformation of cross‐strata and a model of their association is presented. Most of these structures resemble deformation structures previously described in wetted sand, but their association, indicating (1) collapse due to volume reduction and (2) the alternation of deformed and undeformed sedimentary units, form diagnostic indicators of cold‐climate aeolian deposits.