Mineral dust aerosols recently collected at the high-altitude
Jungfraujoch research station (46 degrees 33'51 `' N, 7 degrees 59'06 `'
E; 3580 m a.s.l.) were compared to mineral dust deposited at the Colle
Gnifetti glacier (45 degrees 52'50 `' N, 7 degrees 52'33 `' E; 4455 m
a.s.l.) over the last millennium. Radiogenic isotope signatures and
backward trajectories analyses indicate that major dust sources are
situated in the north-central to north-western part of the Saharan
desert. Less radiogenic Sr isotopic compositions of PM10 aerosols and of
mineral particles deposited during periods of low dust transfer likely
result from the enhancement of the background chemically-weathered
Saharan source. Saharan dust mobilization and transport were relatively
reduced during the second part of the Little Ice Age (ca. 1690-1870)
except within the greatest Saharan dust event deposited around 1770.
After ca. 1870, sustained dust deposition suggests that increased
mineral dust transport over the Alps during the last century could be
due to stronger spring/summer North Atlantic southwesterlies and drier
winters in North Africa. On the other hand, increasing carbonaceous
particle emissions from fossil fuel combustion combined to a higher lead
enrichment factor point to concomitant anthropogenic sources of
particulate pollutants reaching high-altitude European glaciers during
the last century.