Comment: a test of the englacial thrusting hypothesis of ;hummocky' moraine formation

Areas of apparently chaotically organised moraine mounds and ridges are commonly associated with British Younger Dryas glaciers, and are also found at many contemporary glacier margins (Boulton & Eyles 1979; Benn 1992; Bennett & Boulton 1993b; Hambrey et al. 1997). Particularly in the British context, such landforms have commonly been referred to as ‘hummocky’ moraine. Whilst this term is undoubtedly an apt description of their morphology, genetic connotations have become attached to it, with some authors using it exclusively to refer to sediment-landform associations associated with wasting ice (e.g. Benn & Evans 1998: p. 483). Work undertaken over the last two decades has demonstrated that British Younger Dryas ‘hummocky’ moraine only rarely formed in association with stagnant ice, and it is now clear that they are polygenetic in origin (e.g. Benn 1992; Bennett & Boulton 1993b). For this reason the non-genetic, and similarly descriptive, ‘moraine-mound complex’ has been proposed for features of undetermined origin (Bennett et al. 1996b), and this term is adopted here.