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Vico volcano, Italy

volcano number: none (not Holocene)

summit elevation: XXX m

location: XXXXX°N, XXXXX°E

The following is summarized from De Rita (1993).

The caldera of the Vico volcano, south of Viterbo (Lazio) and adjacent to Monte Cimino (above). Part of the picturesque caldera lake and the intracaldera cone of Monte Venere carrying a light dusting of snow are visible in this winter image, taken on 2 January 1995. The caldera collapsed some 150 ka ago, and the last activity of Monte Venere took place some 95 ka ago.

Geological map of Vico volcano and its products, taken from De Rita (1993).

In contrast with most of the other volcanoes in the Lazio region, Vico has a fairly simple structure, constituted by a central stratovolcano truncated by a caldera which in turn contains a postcaldera cone.

The volcanic history of Vico spans the period from 0.8 Ma until about 85-90 ka ago. Four phases of activity are distinguished. During the first, lasting from 0.8 until 0.4 Ma ago, latitic to trachytic magmas were erupted from minor eruptive centers to form numerous air fall units and lava flows.
Essentially effusive activity characterized the second period, from 0.35 until 0.2 Ma ago, now being concentrated on a central volcano. During this period, a major stratovolcano was constructed. Its early products were leucite trachytes but later lavas were more strongly undersaturated tephritic phonolites to phonolitic tephrites. The youngest lavas of this period are phonolitic.
The third phase, from 0.2 until 0.15 Ma ago, was much more explosive. Four major ignimbrite units (named A, B, C and D) with associated air fall deposits stem from cataclysmic Plinian eruptions that were accompanied or succeded by collapse of a 7.5 km diameter caldera which is now filled with the beautiful Lago di Vico.
The fourth and final phase of volcanism at Vico was strongly influenced by the presence of a lake filling the newly formed caldera, and thus was violently hydromagmatic. Only in its very final stage the character of the eruptions became magmatic again, building the cone of Monte Venere that lies eccentrically in the N part of the caldera basin. The activity of this fourth period lasted from 140 to about 90 ka ago.

View down into the northern part of Vico caldera, on 7 March 1994, from the NW. The youthful post-caldera cone Monte Venere is visible in the center. Note the sharp outline of lava flows at its base.

Sunset over Lago di Vico on 7 March 1994. View is to the W, showing high W rim of the caldera (the remainder of the pre-caldera strato-volcano on whose E flank the caldera was eccentrically formed), called Monte Fogliano.

Etruscan tombs are abundant in the Viterbo region. These are near the village of Barbarano Romano, a few km south of the Vico caldera, cut into the ignibrites of the cataclysmic, caldera-forming eruptions from that volcano. Taken on 28 December 1994.

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