Correlation of knickpoint retreat rates and isostatic rebound in Scotland

Abstract

Isostatic rebound in Scotland is a topic that many have studied and modelled. However, relating this to river incision and knickpoint retreat is something that is not well understood in this area. Knickpoints are locations along rivers where there is a drastic change in slope such as a waterfall or steep rapids, often with heights of 60-110m (Berlin and Anderson, 2007). These naturally move upstream over time due to a number of different reasons, such as the geology of the bedrock or erosion of the channel. However, in some cases, these are related to uplift of the landscape. This process is currently in motion in Scotland after the retreat of the ice after the last glacial maximum.

Using DEMs and river analysis tools, it is possible to locate knickpoints in different drainage areas. The aim of this paper is to determine if knickpoints are an accurate recorder of isostatic rebound in Scotland. Factors including basin size, channel width, stream discharge and sediment flow can also affect the retreat rates of knickpoints, therefore correlating them to isostatic rebound alone can be challenging (Castillo et al, 2013). It is yet unknown if there is a correlation between knickpoint retreat and uplift in Scotland, which is why this study is important for the development and understanding of this topic. Here, a full analysis of knickpoints in Scotland and their correlation to isostatic rebound is given. This report will attempt to shed light on how isostatic rebound has, and still is, influencing the landscape across Scotland.