Geoscience Reference
In-Depth Information
18
African and Arabian deserts
Il serait cependant imprudent d'imaginer que l'heure des syntheses
veritables a dej a sonne: le Sahara est d'une ampleur oceanique, les
lieux serieusement etudies y demeurent punctiformes, il subsiste encore
nombre d'incertitudes, notamment dans le detail des chronologies
paleoclimatiques ou des stratigraphies du Pleistocene. Il faut l'avouer:
la part de l'hypothese reste necessairement tres considerable,
on doit honnetement le reconnaıtre.
Nevertheless, we would be unwise to delude ourselves that the time is
ripe for a definitive account. The Sahara is as large as the ocean, and
the sites studied in depth remain mere pinpricks upon its surface.
Many issues remain unresolved, notably the detailed chronology
of climatic changes and of Pleistocene stratigraphic sequences.
The working hypothesis still has a major role to play,
and honesty requires us to recognise this fact.
Theodore Monod (1902-2000)
The Sahara and the Nile
(1980, foreword, pp. xiii, xv)
18.1 Introduction
The aim of this chapter is to provide a synthesis of the Cenozoic and, in particular, the
Quaternary environments of the deserts of Africa and peninsular Arabia, including
the Kalahari, Namib, Sahara, Afar, East African Rift, Sinai, Negev, Arabia, Yemen
and Oman. Much of the evidence has already been reviewed in the earlier specialist
chapters but in a fragmentary fashion, so an overview is warranted. Because the
tropical northern deserts are more or less contiguous, it is appropriate to treat them
together while noting any important differences. We conclude with the southern
African deserts.
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