Stromboli volcano, Aeolian Islands (Isole Eolie), Sicily, Italy

GEOLOGICAL EVOLUTION OF STROMBOLI

Geological map of Stromboli, from Hornig-Kjarsgaard et al. (1993). Click on image to obtain large version and legend.

After the pioneering studies by Cortese & Sabatini (1892) and Bergeat (1899), the geological evolution of Stromboli has for a long time been ignored, probably because studies were concentrated on the persistent eruptive activity. The first reasonable modern geological study of the island was by Rosi (1980) who recognized four major stratigraphic units: Paleostromboli, Vancori, Neostromboli and Recent Sciara. The following is extracted from the much more detailed stratigraphy established by Hornig-Kjarsgaard et al. (1993), with additions based on recent work by Kokelaar & Romagnoli (1995) and Bertagnini & Landi (1996).

Traces of a violent past: this outcrop at the W coast of Stromboli cuts through scoria and lapilli fall deposits of the Scari formation (Hornig-Kjarsgaard et al. 1993). The prominent light-colored horizon is a distal tephra deposit erupted on the island of Ischia (!), between 40 and 60 ka ago.

In the stratigraphy of Hornig-Kjarsgaard et al. (1993) and on the geological map of Stromboli by Keller et al. (1993), the following volcanostratigraphic units are identified:
• Strombolicchio
  • 1) Strombolicchio eroded volcanic neck
• Paleostromboli
  • 2) Lower Paleostromboli (PST) I lavas
  • 3) PST I Pyroclastic Series
  • 4) Upper PST I lavas
  • 5) Lower Rina lavas
  • 6) Omo lavas
  • 7) Vallone Rina-Malo Passo Pyroclastics
  • 8) Middle Vallone di Rina lavas
  • 9) Upper Rina Lavas
  • 10) Aghiastro lavas and pyroclastics
  • 11) Cavono pyroclastics
  • 12) Diatreme vent of Malo Passo
• Vancori and Scari
  • 13) Lower Scari Tuffs (LST)
  • 14) Scari Lava
  • 15) Upper Scari Tuffs (UST)
  • 15a) Lower Vancori and Middle Vancori Pyroclastics
  • 16a, b) Lower Vancori (Lower Vancori-a) and Frontone lavas (Lower Vancori-b)
  • 17) Middle Vancori lavas
  • 18) Upper Vancori breccias
  • 19) Upper Vancori lavas
  • 20) Frontone breccias
  • 21) Roisa scoriae and lavas
• Neostromboli
  • 22) Neostromboli lavas
  • 23) Timpone del Fuoco lavas
  • 24) Labronzo lavas
  • 25) Nel-Cannestrà lavas
  • 26) Lazzaro pyroclastics
• Recent Stromboli
  • San Bartolo lavas
  • Pizzo sopra la Fossa pyroclastics
  • Sub-recent Sciara lavas
  • Recent Sciara activity
  • Epiclastic volcanic materials

Geologically the oldest part of the Stromboli volcanic system, the "neck" of Strombolicchio (a remnant of a volcanic conduit) rises from the sea about 1.5 km NE of Stromboli (in the background). On this photograph, taken on the early morning of 29 March 1990, a dense volcanic gas plume is being carried down to the village of Stromboli, causing a slight smell of sulfur even beyond Strombolicchio.

Beds of phreatomagmatic deposits rich in accretionary lapilli. This outcrop, photographed in September 1989, does not exist anymore since it lies on an area now in private property. Its location is between the two main fractions of Stromboli village, San Vincenzo and San Bartolo. The deposits may be correlated with violent explosive volcanism associated with the sector collapse at Stromboli that left the Sciara depression.

More will be added!

Page set up in late 1995, last modified on 21 July 1996