Geoscience Reference
In-Depth Information
1.2
Arid zone distinctiveness and the
quest for explanation
accounts in the works of early Europeans were usually
but by-products of the reasons for their being in deserts
in the first place. This also helps to explain the sec-
ond characteristic, the superficiality of early reports and
studies.
The third characteristic attributed above to early works,
secularity, arose because national groups tended, until
relatively recently, to confine their interests to particu-
lar deserts. In Africa, Asia and Australia, early geomor-
phological investigations were heavily influenced by the
distribution of the impacts of European colonialism. Thus
Flammand's (1899) account from the Sahara, Passarge's
(1904) two volumes on the Kalahari and numerous reports
from Australia (e.g. Sturt, 1833; Mitchell, 1837; Spencer,
1896) reflect broader colonial interests of their time. It
has been noted, and is now increasingly realised as solu-
tions are sought to dryland environmental problems (e.g.
Mortimore, 1989; Thomas and Middleton, 1994; Thomas
and Twyman, 2004), that the environmental knowledge
vested in indigenous populations was, and remains, con-
siderable and meritorious. Yet this was usually either ig-
nored or unrealised by Europeans entering arid environ-
ments for the first time in the nineteenth and through much
of the twentieth centuries: such people often saw deserts
through eyes more accustomed to their starkly contrast-
ing points of origin, leading to a preoccupation in some
cases with the spectacular and unusual landforms they
encountered in deserts.
There were, of course, exceptions to these character-
istics, even in the nineteenth century. Perhaps most no-
table were the investigations in the southwestern United
States, often with a geomorphological slant, of John
Wesley Powell (1875, 1878) and Grove Karl Gilbert
(1875, 1877, 1895), the latter regarded by many as the
father of modern geomorphology. Their activities were
driven by a governmental quest to expand the frontiers of
(European) utilisation of North America and their works
were essentially early forms of resource appraisal. Some
of the early accounts of the geomorphology of the Aus-
tralian deserts had a similar basis; for example, Thomas
Mitchell wrote:
Early accounts of arid landscapes may, however, be of
restricted geomorphological value for a different reason:
their focus on unusual and spectacular features was often
at the expense of representativeness (but also see Chapter
4, showing that accounts could also focus on the monotony
of some dryland regional landscapes). The lack of reliable,
systematic, information and data was one reason why
theory in arid geomorphology changed rapidly through
the first six decades of the twentieth century. As Goudie
(1985, p. 122) noted:
A prime feature of desert geomorphological research
over the past century or so has been the rapidity with
which ideas have changed, and the dramatic way in
which ideas have gone in and out of fashion. This
reflects the fact that hypothesis formulation has of-
ten preceded detailed and reliable information on
form and process, and the fact that different workers
have written about different areas where the relative
importance of different processes may vary substan-
tially.
Within these changing ideas was a view that arid en-
vironments are distinct, even unique, in terms of the op-
eration of geomorphological processes and their resultant
landscape outcomes. Early quests for synthesising expla-
nations sought generalisations that were deliberately dis-
tinct from those developed for other environments. Davies
(1905) produced his cycle of erosion for arid environ-
ments based on the belief that fluvial processes in drylands
produced distinct outcomes at the landscape scale. This
notion of distinctiveness was clearly also present in mor-
phogentic or climatic geomorphology models of explana-
tion (e.g. Birot, 1960; Budel, 1963; Tricart and Cailleux,
1969). While the very terms 'drylands', 'arid zone' and
so on clearly imply a climatic delimitation of the extent
of these environments, it is debatable whether sweeping
models of desert geomorphic explanation are justified,
for three reasons. First, notwithstanding that there may
be 'a world of difference in the landscapes and geomor-
phological processes that occur in these different climatic
zones' [
within
arid environments] (Goudie, 2002, p. 5) is
that drylands themselves are not internally homogeneous;
indeed they are markedly diverse climatologically and
tectonically (see Chapter 2), which affects seasonality,
plant cover, landscape erodibility, sediment types, sedi-
ment availability and so on. Second, today's arid regions
After summounting the barriers of parched deserts
and hostile barbarians, I had at last at length the
satisfaction of overlooking from a pyramid of granite
a much better country (Mitchell, 1837, p. 275).
We had at last discovered a country ready for
the reception of civilised man. (Mitchell, 1837,
p. 171)
