Discussion: 'Streamlined erosional residuals and drumlins in central British Columbia, Canada' by J. Donald McClenagan, (2013) Geomorphology 189, 41-54

摘要

McClenagan (2013) presents a model to explain streamlined erosional residuals or drumlins on uplands and lowlands in the plateau region of central British Columbia, Canada. In this discussion paper, we note that McClenagan (2013) has not adequately discussed previous relevant work in the region, and we argue that additional analyses and evidence are required to substantiate this new model. The hypothesis offered for the origin of the plateau landscape, specifically catastrophic glaciofluvial activity, differs significantly from a model based on glacial erosion and deformation that has been developed from field-based research over the past six decades. We discuss four critical points relating to the proposed model: (1) the current geological model for the plateau region of central British Columbia; (2) theory of glacial dispersal; (3) existing hypotheses for the formation of drumlins and other glacial landforms; and (4) theoretical glacial erosion modeling. We further suggest that the model cannot be substantiated without sedimentological or morphological field evidence for water bodies argued to be the source of the proposed megaflood or megafloods.