Impact of Holocene Explosive Activity of Etna Volcano (Italy) Estimated by Pollen Analysis of Marine Sediments
by
Sabina Rossi
Dipartimento di Scienze Chimiche e Ambientali, Università dell'Insubria, Via Vallegio 11, 22100, Como, Italia
Coauthors: Luigina Vezzoli

For its geographical position at the centre of the Mediterranean Sea, Sicily represents a key-site for estimating the environmental evolution of this region during the Holocene. In the Etna area environmental changes are related not only to climate variations and human impact, but also to the volcanic activity of Mount Etna. The historical explosive activity of Etna is characterized by several basaltic eruptions. In order to evidence the relationship between the explosive activity and the environment evolution, we have undertaken stratigraphical, mineralogical, paleomagnetic, pedological and palynological analyses on marine and continental deposits. Marine cores were collected along the Catania coast, SE to Mt. Etna, a favourable zone for recording the pyroclastic deposits ejected by the volcano.

Pollen analysis was carried out on the ET99-18 deep-sea core, located at 1, 083 m b.s.l., in the Jonian Sea, east of the Etna edifice (37^° 32¢39^¢¢N, 15^° 15¢51^¢¢E), over 200 cm of muddy marine sediments representing the last 4000 years. These sediments include the FG tephra (90 cm from core-top, representing the 122 BC plinian basaltic eruption products) and FL tephra (163-172 cm from core-top, representing the Sicani eruption products, 3150±60 BP).

In the lower part of the sequence covered by the pollen diagram, vegetation is dominated by grasslands and wooded steppe, typical of arid-temperate stands. Quercus forests were developed in the moister zones, while Fagus, Abies and Pinus woodlands were present at higher altitudes of the Etna edifice.

A clear variation in the pollen assemblage and a decreasing of pollen concentration verifies in correspondence of the tephra layers FG. Here a decrease in cultivated plants (Corylus, Olea, Vitis) and natural forests is associated with an expansion of steppic grasslands.

In the last 2000 years, after a new forest expansion, mainly by mesophilous elements (evergreen and deciduous Quercus), the progressive reduction of forested areas and the development of steppic communities, would suggest an increase of human exploitation in the region.

Date received: July 21, 2005

Copyright © 2005 by the author(s). The author(s) of this document and the organizers of the conference have granted their consent to include this abstract in Atlas Conferences Inc. Document # caqy-46.