Reply: Application of the QDa-Md method of environmental discrimination to particle size analyses of fine sediments by pipette and sedigraph methods

Although it may be inappropriate to apply the QDa-Md method to grain-size distribution data of bimodal and polymodal sediments, the aim of the study (R. W. Duck, Earth Surface Processes and Landforms. 1994, 19, 525-529) was not to defend this methodology. It was to determine whether or not the modern SediGraph yielded particle size data, for a suite of fine-grained, 'quiet water' sediments, which are accommodated by the appropriate QDa-Md trend envelopes, originally established on the basis of the pipette method. That this was shown to be the case, despite the considerable differences in the values of QDa and Md recorded in comparative analyses, demonstrates the applicability of the method to SediGraph-derived data for fine-grained sediments and in no way invalidates the approach adopted.particle size.