MT. ETNA
Mt. Etna is a regularly-erupting volcano along the
eastern margin of Sicily, a large Mediterranean island offshore from southern
Italy. Historically, Etna's eruptions are spectacularly gorgeous,
especially when viewed at night. Etna is also famous for blowing smoke rings. The
volcanic ash sample shown below is from an eruption during the 2000s (see photos of recent
Etna lava & ash eruptions). The sample comes from a November 2002
ash fall, one of many individual eruptive events during its nearly continuous
26 October 2002 to 28 January 2003 eruption.
Much of Etna's erupted material is trachybasalt.
Trachybasalt has the same general physical & chemical & mineralogical
characteristics of basalt, but is significantly more alkaline (relatively high
Na & K content). Most of Etna's October 2002-January 2003 lavas &
ashes are potassic/alkaline basalts and trachybasalts. The sample shown
below is fairly fine-grained volcanic ash - most of the individual ash grains
are glassy textured. So, a decent descriptor for the sample could be glassy
trachybasalt volcanic ash.
Glassy trachybasalt volcanic ash (field of view ~5.2 cm across) from a November 2002
ash fall eruption of Mt. Etna in eastern Sicily.