Sediments and landforms in an upland glaciated-valleylandsystem: upper Ennerdale, English Lake District

摘要

The genesis of moraines associated with British glaciers of Younger Dryas age has proved con-troversial in recent years. A number of alternative hypotheses exist and, whilst it is generally acceptedthat such features are polygenetic in origin, some workers have argued that not all of the proposedmechanisms are valid. This paper seeks to explore these issues, using a case study from the EnglishLake District. A landsystems approach is adopted, integrating information at a variety of spatialscales to explain the development of the sediment-landform associations in upper Ennerdale.The evidence suggests that landform development resulted from a combination of ice-marginaldeposition and englacial thrusting. It is probable that thrusting resulted from flow compressionagainst a reverse bedrock slope, combined with the confluence of ice from two separate sourceareas. It is argued that, whilst englacial thrust moraines may not be commonly associated withBritish Younger Dryas glaciers, under certain conditions englacial thrusting is an important pro-cess in landform development.