Vulcano and Lipari

Vulcano: Crystalline and Molten sulphur

Photos copyright Jürg Alean (JA), Marco Fulle (MF) and Gunter Militzer (GM).

Vulcano: Crystalline and Molten sulphur
Spectacular fumaroles are Vulcano's speciality. The sulphur needles around this vent are around 2cm long (JA).
Vulcano: Crystalline and Molten sulphur
Within some fumaroles not only sulphur but also the white mineral gypsum (calcium sulphate) is deposited (JA).
Vulcano: Crystalline and Molten sulphur
In the fumaroles with the highest temperatures sulphur melts and forms drops resembling amber (MF).
Vulcano: Crystalline and Molten sulphur
Another drop of molten suphur reflecting the sun: drops have diameters of typically one centimetre (MF).
Vulcano: Crystalline and Molten sulphur
Starting in 1986 fumarole temperatures rose from about 300°C raising some concern that magma might be intruding at shallow depths beneath Vulcano (MF).
Vulcano: Crystalline and Molten sulphur
Fumarole temperatures peaked in 1993 when almost 700° C were measured. Later there was a slow decrease of the measured maximum temperatures (MF).
Vulcano: Crystalline and Molten sulphur
Liquid sulphur sometimes forms miniature flows 20cm or more in length. Note colour differences, cf. next image (MF).
Vulcano: Crystalline and Molten sulphur
The viscosity of liquid sulphur increases above 200°C due to the formation of polymer chains, and it becomes dark red . These drops are about 3cm long (MF).
Vulcano: Crystalline and Molten sulphur
Close-up of sulphur crystals in the shape of needles (MF).
Vulcano: Crystalline and Molten sulphur
Higher magnification shows fractal structure: smaller needles on bigger ones. Condensed drops of water at upper-left (MF).
Vulcano: Crystalline and Molten sulphur
Here small flows of liquid sulphur form a pond 5cm across (bottom of photo, MF).
Vulcano: Crystalline and Molten sulphur
Other spectacular drops of liquid sulphur among yellow needles, the largest about 12mm in length (GM).
Vulcano: Crystalline and Molten sulphur
sulphur needles on the rims around fumarolic vents (MF).
Vulcano: Crystalline and Molten sulphur
While sulphur crystals near the vent maintain their shape, the ones further from the hot gas (bottom) weather quickly (MF).
Vulcano: Crystalline and Molten sulphur
Thin layers of Calcium sulphate around the hottest vents of a fumarole (MF).
Vulcano: Crystalline and Molten sulphur
Out of this world: Steaming vent of a fumarole - an alien landscape? (MF)