Reply to comment by Rob Westaway on “Review of tufa deposition and palaeohydrological conditions in the White Peak, Derbyshire, UK: implications for Quaternary landscape evolution.”

Abstract

We thank Westaway (2012) for his interesting discussion of the uplift rates derived from the Alport tufa and its geomorphological setting. His comments highlight the tentative nature of geological approaches to determining rates of glacio-isostatic and tectonic uplift. In particular, Westaway (2012) questions the validity of the uplift rates that were presented within our original paper (Banks et al., 2012) and we welcome the opportunity to clarify this further. We also welcome the opportunity to comment on the practicalities of determining uplift measurements from karst environments within the wider, long-term, tectonic evolution of the Peak District.Westaway (2012) makes reference to two (of four) cited incision rates (Banks et al., 2012) that correspond with the Late Ipswichian to Holocene period, and the end of the Anglian to present and compares them with values that span the entire Quaternary (Westaway 2009(Westaway , 2012. Accordingly, it should be noted that the uplift rates that were presented by Banks et al. (2012) were linked to specific durations, which also included periods of accelerated down-cutting during the Devensian to Holocene (0.165 mm a Based on geodynamic modelling Westaway (2009 and 2012) presents a case for on-going hot-spot related lowering of viscosity in the lower crust as the driver for lower crustal flow coupled to surface process and resulting in elevated rates of uplift in northern England. This contrasts with the Shennan et al. GIA model, which assumes an elastic lithosphere and viscous structure within the mantle. Modelling undertaken by Westaway (2009) uses observed uplift that is, in part, estimated from "karstic base-level lowering". Calculation of uplift rates in karst environments is particularly difficult. This is due to the paucity of dated surfaces and the hydrogeological complexity largely due to the solubility of limestones, which facilitates subsurface flow at the expense of surface flow. Accordingly, Westaway (2009Westaway ( , 2012) is forced to draw from an extensive literature review of karstic levels, using speleothem dating as the basis for calculating uplift rates. It is assumed that the dated karstic levels