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With the advent of the Total Ozone Mapping Spectrometer (TOMS), more consistent
global measurements of dust plumes became possible, and it also became possible to
follow dust plume movements over time (Goudie and Middleton, 2001 ; Maher et al.,
2010 ). A dust plume shows the generalised path followed by dust-storms.
The aims of this chapter are to examine the origin, sources and distribution of
eolian desert dust around the world and to evaluate the environments in which the
dust is mobilised, transported and deposited. We then illustrate how this information
has been used to reconstruct past environmental (and climatic) fluctuations with the
evidence preserved in both terrestrial and marine sediments.
9.2 World distribution of desert dust plumes
Changes in the amount of wind-blown dust mobilised, transported and deposited on
land and sea are both a cause and a consequence of global and regional climatic
change (Harrison et al., 2001 ; Arimoto, 2001 ; Goudie and Middleton, 2001 ; Goudie
and Middleton, 2006 ; Goudie, 2008 ; Maher et al., 2010 ; McGee et al., 2010 ). The
present-day dust flux is variably estimated at between 1 and 3.5 Pg yr 1 ,ofwhich
between 0.3 and 2 Pg yr 1 are deposited over the ocean (1 Pg is 1
10 15 g). A number
of major dust plumes have been identified using satellite imagery, with two major
source areas identified as the deserts of central Asia, north-west of the Loess Plateau
of China (Liu, 1985 ; Kukla, 1987 ; Kohfeld and Harrison, 2001a ; Pullen et al., 2011 ),
and the Bodele Depression in the Chad Basin of the southern Sahara (Goudie and
Middleton, 2001 ; Goudie, 2008 ). Smaller plumes emanating from Patagonia, south-
west Africa, and north-west and south-east Australia have also been recognised (Pewe,
1981 ; Kohfeld and Harrison, 2001a ). Figure 9.1 shows the main dust source areas
and the general directions of dust transport. However, this is to present a somewhat
oversimplified picture of dust movement.
In the case of North Africa, for example, Coude-Gaussen and Rognon ( 1983 )have
distinguished four main dust trajectories. One flows to the west along the south-
ern margin of the Sahara, extending across the Atlantic via Barbados and across the
equator to theAmazonBasin in SouthAmerica. Another flows west across the northern
Sahara and out into the Atlantic, eventually reaching North America. A third dust path
flows northwards across the Mediterranean to reach southern France and the Alps. In
exceptional cases, this plume may reach England (Pitty, 1968 ; Goudie and Middleton,
2006 ), Ireland and even Sweden (Franzen et al., 1994 ). A fourth North African dust
path flows from the central and northern Sahara across Egypt and the Mediterranean
to Israel and Arabia. Moreno et al. ( 2002 ) have examined the late Quaternary Saharan
dust record preserved in a marine core in the Alboran Sea located in the western Medi-
terranean between Spain and Morocco. They found that enhanced northward trans-
port of Saharan dust coincided with North Atlantic Heinrich events (see Chapter 3 )
and with times of strengthened high-northern-latitude atmospheric circulation.
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