Relict non-glacial surfaces occur within many formerly glaciated landscapes and contain
important information on past surface processes and long-term landscape evolution
(Goodfellow, 2007). While cosmogenic dating has confirmed the antiquity of
relict non-glacial surfaces, the processes that contribute to their evolution and, consequently,
the time scales over which they develop remain poorly understood. Of particular
importance is the possibility that relict non-glacial surfaces may provide geomorphic
markers for the reconstruction of preglacial landscapes, which would allow
subsequent glacial erosion to be quantified. Furthermore, relict non-glacial surfaces
may also hold information on preglacial and interglacial environmental conditions.
An investigation of relict non-glacial surfaces was undertaken through remote sensing,
mapping and analysis of surfaces in a GIS, and regolith studies involving cosmogenic
dating-, grain size-, X-ray diffraction-, and X-ray fluorescence analyses. On
the basis of these on-going studies, we show that depending on spatial variables such
as bedrock lithology, slope, regolith thickness, and the abundance of fine matrix and
water some surfaces are denuding very slowly, while others display more rapid denudation.
High spatial variability in denudation rates results in changing surface morphologies
over time. Rather than being static preglacial remnants, relict non-glacial
surfaces are dynamic features that have evolved during the Quaternary. While reconstructions
of preglacial landscapes and subsequent quantifications of glacial erosion
from relict non-glacial surfaces remain valid, the Quaternary evolution of these surfaces
should also be considered.
Goodfellow B.W., 2007. Relict non-glacial surfaces in formerly glaciated landscapes.
Earth-Science Reviews, 80(1-2): 47-73.