Dryland system variability - Arid Zone Geomorphology - page 57

Close analysis, in the field or via remote sensing, shows
that even the great flat desert expanses in shield contexts
possess marked internal geomorphological variability. Ul-
timately, it is the scale of analysis that determines how
varying or unvarying different dryland regions are. The
Kalahari may be a large extent of sand, covering up to
2.5 million km 2 when its northern most, equator-ward
extensions (that are not today arid) are included in as-
sessments, but within that total area, particularly when
evidence of past climatic events and conditions, and local
tectonic activity are taken into account, significant geo-
morphological and sedimentological variability emerges.
This is both in terms of the operation of geomorphologi-
cal processes in the past and in terms of the sensitivity of
different areas to specific processes today.
Since the 1970s, satellite imagery has contributed
markedly to the recognition of within- and between-
dryland geomorphic variability. Couple to this the ad-
vances that have occurred in the capacity to unravel the
role of past environmental change and tectonic activity,
and the growth in application of robust and contextu-
alised (rather than generalised) geomorphological pro-
cesses studies (Thomas and Wiggs, 2008), and a better
picture emerges: not only of the diversity of dryland re-
gions but in the explanations for that diversity. No longer
is it legitimate to overgeneralise about the geomorphol-
ogy of arid regions, because the capacity exists to base
interpretation upon an ever-growing recognition of the
complexity of arid environmental systems and the occur-
rence and interplay of the geomorphological processes
that operate, and have operated, within them.

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