This paper uses the elevation-relief ratio to constrain the horizontal and vertical extent of sub-horizontal denudation surfaces in Wales, United Kingdom.
Key words: sub-horizontal denudation surfaces, elevation-relief ratio, SRTM data, ESRI ArcMap, Wales.
This paper builds upon that theme by using the 3 arc-second NASA Satellite Radar Topographic Mission (SRTM) DEM in order to elucidate the horizontal and vertical extent of sub-horizontal denudation surfaces within Wales, United Kingdom (Figure 1).
The overall aim of the present paper is to demonstrate the value of the elevation-relief ratio as a geomorphological tool, which is able to analytically identify sub-horizontal denudation surfaces within heavily dissected landscapes; therefore, the elevation-relief ratio may be applied in a diverse range of geological and tectonic settings beyond the passive continental margin of northwest Europe.
00 represent sub-horizontal denudation surfaces as it is these that are characterized by a generally convex morphology.
The only previous attempt to define the complete suite of sub-horizontal denudation surfaces in Wales was that of Brown (1960); surfaces were mapped through the integration of topographic map analysis and field investigation.
60), whilst the maps presented in column (ii) depict only the areas defined as sub-horizontal denudation surfaces through the application of the elevation-relief ratio (i.
Initially the most conspicuous characteristic of this histogram is that the altitudinal peaks become increasingly prominent both as the histograms move from elevation (Figure 7a), through to sub-horizontal surfaces (Figures 7b, 7c, 7d, 7e), and then sub-horizontal denudation surfaces (Figures 7f, 7g, 7h, 7i), and as the size of the circular neighbourhood increases (i.
For example, those sub-horizontal denudation surfaces recognized where the elevation-relief ratio was determined from a circular neighbourhood with a radius of 24 grid cells can be observed in the other histograms, but usually only to a far lesser extent; however, such surfaces are difficult to recognize within the altitude-frequency histogram of Wales.
In this study four sub-horizontal denudation surfaces are shown at lower elevations in the altitude-frequency histograms; the prominence of these surfaces decreases with elevation.
The overall aim of this paper was to demonstrate the value of the elevation-relief ratio as a geomorphological tool, which is able to analytically identify sub-horizontal denudation surfaces within the heavily dissected landscape of Wales.