Geoscience Reference
In-Depth Information
Figure 8.1. Sand dunes immediately east of the Aır Mountains, south-central Sahara.
(Photo: J. D. Clark.)
the sheer beauty and symmetry of mobile dunes - a feature commented on at length
by the doyen of dune studies, Ralph Bagnold, during his travels in the Libyan Desert
in the 1920s and early 1930s (Bagnold,
1935
), in his unsurpassed account of
The
Physics of Blown Sand and Desert Dunes
(Bagnold,
1941
) and in his very readable
autobiography (Bagnold,
1990
). The focus of this chapter is on the utility of dunes
as paleoclimatic indicators. For details of the dynamics of eolian sand movement and
more comprehensive accounts of desert dunes, the interested reader should consult
Figure 8.2. Progressive evolution of a barchan dune into a linear dune, showing
associated sand-moving wind direction. (After Sparks,
1972
, modified fromBagnold,
1941
.)
