The geomorphology of central Edinburgh

Abstract

For a 2.0 by 2.8 km. area in central Edinburgh about 1400 borehole records have been collected. From these records three large‐scale maps have been constructed showing respectively rockhead altitude, drift thickness and drift composition. These maps can be of assistance in planning and costing future site investigations. Along with other data the maps also provide information about the geomorphology of the city centre. Trenches cut by glacier ice where deflected by resistant rock masses are clearly revealed and it can be inferred that a thickness of at least 150 m. of rock has been removed near Salisbury Crags and over 105 m. by the Castle Rock. In addition to the well‐known crag‐and‐tail effect some hills appear to have influenced glacial erosion for a considerable distance in the opposite direction. Erosion and deposition by glacial melt‐water rivers has occurred in the area and there is evidence for several former lakes. The presence of lateglacial lake deposits beneath a solifluction layer may be inferred in the former Holyrood Loch site, while thick boulder deposits by Calton Hill probably accumulated when a periglacial climate prevailed.