63 Observations and Modeling of the Palaeodust Cycle

Tuesday, 29 July 2003
8:00 AM - 12:00 PM

LATE QUATERNARY TRANSPORT OF SAHARAN DUST TO SOUTHERN EUROPE

Paper number: 63-10
Program: SYMPOSIA
Time: 10:50 AM – 11:10 AM

Authors

  • D. Magri Presenting Author
    Univ La Sapienza, Roma, N/A
  • B. Narcisi
    ENEA, Roma, N/A
  • I. Parra
    Observatorio de Impactos Climáticos del Levante Almeriense, Garrucha (Almeria), N/A

Abstract

The mineralogical analyses of two continuous lacustrine records (Lagaccione and Lago di Vico) show that significant dust deposition occurred in central Italy throughout the last 100,000 years (Narcisi, 2000). Aeolian quartz is present along the entire length of the two cores, particularly during OIS 4 and 2, while lower contents of quartz are found during interglacial/interstadial phases. The need of detecting the source area for this mineral dust has urged a comparison with the pollen data available for the same cores. A clear coincidence is found between enhanced dust values and steppe vegetation. Besides, the presence of Cedrus pollen in the Italian records provides indisputable evidence of aeolian transportation from Africa. In fact, this tree pollen has a well-defined source area on the Maghreb mountains in Morocco and Algeria and can be transported over long distances. A survey of pollen records from southwest Europe shows that Cedrus pollen is found over a large geographic area during the last glacial period, and occasionally in the forest dominated periods of the interglacials (Magri and Parra, 2002).

These observations lead to the following conclusions: 1) aeolian activity over the western Mediterranean increased during the last glacial period, with a significant component of Saharan origin, 2) from the methodological point of view, specific pollen types can provide information on the source area, path and arrival of dust, complementing sedimentological information on the amount of transported dust, 3) a deeper understanding is needed of the possible relationships between palaeoenvironmental changes in southern Europe and the subtropical and northern regions of Africa. In fact the Sahara desert, impending the Mediterranean, is the largest modern source of atmospheric dust and may play a very important role in Mediterranean aridification.