The eruptive history of Pantelleria has been marked by the eruption of nine peralkaline ignimbrites,with inter-ignimbrite episodes from small, local volcanic centres. New whole-rock geochemicaldata are presented for seven ignimbrites and used with published data for younger units to trackcompositional changes with time. From»190 ka, silicicmagmatismwas dominated by comenditic trachyteto comendite compositions, evolving along generally similar liquid lines of descent (LLOD). Thefinal ignimbrite, the Green Tuff (»46 ka), was tapped from a compositionally zoned pantelleritic upperreservoir to a trachytic mush zone. Younger (20–7 ka) silicic magmatism has been relatively smallscale, with compositions similar to the earliest pre-Green Tuff pantelleritic ignimbrite (Zinedi). Thesedata suggest that the comenditic reservoirs may have been emplaced at deeper levels than the pantelleriticreservoirs. While both types of series evolved along similar LLOD dominated by fractionationof alkali feldspar, it is the fractionation of iron that determines whether comendite or pantellerite isproduced. The deeper reservoirs were more oxidizing and wetter, thus leading to the crystallization ofmagnetite and therefore the fractionation of iron.
|Numero di pagine||17|
|Rivista||COMPTES RENDUS. GÉOSCIENCE|
|Stato di pubblicazione||Published - 2021|
All Science Journal Classification (ASJC) codes