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

The genesis of moraines associated with British glaciers of Younger Dryas age has proved controversial in recent years. A number of alternative hypotheses exist and, whilst it is generally accepted that such features are polygenetic in origin, some workers have argued that not all of the proposed mechanisms are valid. This paper seeks to explore these issues, using a case study from the English Lake District. A landsystems approach is adopted, integrating information at a variety of spatial scales to explain the development of the sediment-landform associations in upper Ennerdale. The evidence suggests that landform development resulted from a combination of icemarginal deposition and englacial thrusting. It is probable that thrusting resulted from flow compression against a reverse bedrock slope, combined with the confluence of ice from two separate source areas. It is argued that, whilst englacial thrust moraines may not be commonly associated with British Younger Dryas glaciers, under certain conditions englacial thrusting is an important process in landform development.