Identifying Sources of Aeolian Mineral Dust: Present and Past - Mineral Dust: A Key Player in the Earth System - page 64

a c

b d

Fig. 3.6 Ternary diagrams showing abundances of Sc-Th-La in soils from ( a ) Bermuda, ( b )
Bermuda [enlarged from ( a )], ( c ) Barbados, and ( d ) the Florida Keys and Bahamas. Shown for
comparison are compositions of African dust collected on Barbados and competing volcanic parent
materials (Data from Muhs et al. 2007 , 2012 )

La pole. Olivarez et al. ( 1991 ) found that fine-grained sediments from cores in the
northwestern Pacific Ocean had Sc-Th-La compositions that fell between these two
extremes, although the majority of core samples have compositions closer to average
continental crust (proxied by Chinese loess). They infer from these observations that
Asian dust is a likely source for much of what is seen in northwestern Pacific cores.
On the other hand, cores from the equatorial Pacific, although also showing a hybrid
composition, plot closer to the composition of oceanic crust and other mafic volcanic
rocks, suggesting lesser amounts of input from Asian dust. This interpretation is
consistent with the greater distance of travel for Asian dust to reach the equatorial
latitudes of the Pacific. A similar approach has been used to identify African dust in
soils of western Atlantic islands (Fig. 3.6 ).