Vulsini
Encyclopedia
Vulsini, also known as Volsini volcano
, Vulsini Volcanic District, Vulsini Volcanic Complex and the Vulsinian District, is a circular region of intrusive igneous rock
in Lazio, Italy
, about 87 km (54.1 mi) to the north northwest of Rome
, containing a cluster of caldera
s known to have been active in recent geologic and historical times. Potentially they still are active. The Vulsinian region is one of dozens of intrusive circular regions, most smaller than the Vulsinian, arranged in a band from Campania
through Lazio, called the Roman Comagmatic Province. A comagmatic province is a geologic area of the same type and age igneous rock
deriving from the same crustal magma. The Roman region is post-collisional; that is, the intrusions were not a result of the lateral stresses that created Italy and raised the Apennines, but were subsequent to Italy's creation. The Volsinian is the northermost region.
At relatively low altitude, the Vulsini calderas cover about 2280 square kilometre and contain four Pleistocene
-age depressions known as Bolsena, Latera, Vepe and Montefascione calderas. The latest activity occurred in 104 BC. The largest, the Bolsena caldera, which is roughly 16 km (9.9 mi) across, is filled with the waters of lake Bolsena
, which derive mainly from deep aquifers. Immediately to the northwest are the combined Latera and Vepe calderas, about 8 km (5 mi) by 11 km (6.8 mi). Vepe, to the north of Lake Mezzano
(a very small crater lake west of Lake Bolsena) is what is known as a nested caldera; it arose in the previously existing Latera Caldera. Italian routes SS74 and SS312 follow the rim from Valentano
through Latera
westward, turning off before Mezzano on the other side. In addition the small Montefiascone caldera, also nested, lies between Montefiascone
on its eastern rim and the lake. Two islands in the lake, Bisentina and Martana, were formed from airfall tuff
s in Pompeii-like eruptions. Dozens of other tuff cones dot the region, mainly on the eastern side of the complex.
Volcano
2. Bedrock3. Conduit 4. Base5. Sill6. Dike7. Layers of ash emitted by the volcano8. Flank| 9. Layers of lava emitted by the volcano10. Throat11. Parasitic cone12. Lava flow13. Vent14. Crater15...
, Vulsini Volcanic District, Vulsini Volcanic Complex and the Vulsinian District, is a circular region of intrusive igneous rock
Igneous rock
Igneous rock is one of the three main rock types, the others being sedimentary and metamorphic rock. Igneous rock is formed through the cooling and solidification of magma or lava...
in Lazio, Italy
Italy
Italy , officially the Italian Republic languages]] under the European Charter for Regional or Minority Languages. In each of these, Italy's official name is as follows:;;;;;;;;), is a unitary parliamentary republic in South-Central Europe. To the north it borders France, Switzerland, Austria and...
, about 87 km (54.1 mi) to the north northwest of Rome
Rome
Rome is the capital of Italy and the country's largest and most populated city and comune, with over 2.7 million residents in . The city is located in the central-western portion of the Italian Peninsula, on the Tiber River within the Lazio region of Italy.Rome's history spans two and a half...
, containing a cluster of caldera
Caldera
A caldera is a cauldron-like volcanic feature usually formed by the collapse of land following a volcanic eruption, such as the one at Yellowstone National Park in the US. They are sometimes confused with volcanic craters...
s known to have been active in recent geologic and historical times. Potentially they still are active. The Vulsinian region is one of dozens of intrusive circular regions, most smaller than the Vulsinian, arranged in a band from Campania
Campania
Campania is a region in southern Italy. The region has a population of around 5.8 million people, making it the second-most-populous region of Italy; its total area of 13,590 km² makes it the most densely populated region in the country...
through Lazio, called the Roman Comagmatic Province. A comagmatic province is a geologic area of the same type and age igneous rock
Igneous rock
Igneous rock is one of the three main rock types, the others being sedimentary and metamorphic rock. Igneous rock is formed through the cooling and solidification of magma or lava...
deriving from the same crustal magma. The Roman region is post-collisional; that is, the intrusions were not a result of the lateral stresses that created Italy and raised the Apennines, but were subsequent to Italy's creation. The Volsinian is the northermost region.
At relatively low altitude, the Vulsini calderas cover about 2280 square kilometre and contain four Pleistocene
Pleistocene
The Pleistocene is the epoch from 2,588,000 to 11,700 years BP that spans the world's recent period of repeated glaciations. The name pleistocene is derived from the Greek and ....
-age depressions known as Bolsena, Latera, Vepe and Montefascione calderas. The latest activity occurred in 104 BC. The largest, the Bolsena caldera, which is roughly 16 km (9.9 mi) across, is filled with the waters of lake Bolsena
Lake Bolsena
Lake Bolsena is a crater lake of central Italy, of volcanic origin, which was formed starting 370,000 years ago following the collapse of a caldera of the Vulsini volcanic complex into a deep aquifer. Roman historic records indicate activity of the Vulsini volcano occurred as recently as 104 BC,...
, which derive mainly from deep aquifers. Immediately to the northwest are the combined Latera and Vepe calderas, about 8 km (5 mi) by 11 km (6.8 mi). Vepe, to the north of Lake Mezzano
Lake Mezzano
Lake Mezzano is a small crater lake of central Italy, of volcanic origin, which was formed 400,000 years ago.The lake has a circular shape typical of crater lakes...
(a very small crater lake west of Lake Bolsena) is what is known as a nested caldera; it arose in the previously existing Latera Caldera. Italian routes SS74 and SS312 follow the rim from Valentano
Valentano
thumb|250px|View of Valentano.Valentano is a town and comune of the province of Viterbo, in the Lazio region of central Italy. It is 33 km from the provincial capital, Viterbo.left|thumb|220px|Rocca Farnese in Valentano....
through Latera
Latera
Latera is a small town and comune in the Province of Viterbo, Italy.Situated near Bolsena Lake and Mezzano Lake, is important for volcanic underground activity near the town centre. It has a small rock with a medieval palace by Farnese family, surrounded by medieval stone houses.-History:Latera and...
westward, turning off before Mezzano on the other side. In addition the small Montefiascone caldera, also nested, lies between Montefiascone
Montefiascone
Montefiascone is a town and comune of the province of Viterbo, Italy, located on a hill on the southeast side of Lake Bolsena, 95 km north of GRA .-History:...
on its eastern rim and the lake. Two islands in the lake, Bisentina and Martana, were formed from airfall tuff
Tuff
Tuff is a type of rock consisting of consolidated volcanic ash ejected from vents during a volcanic eruption. Tuff is sometimes called tufa, particularly when used as construction material, although tufa also refers to a quite different rock. Rock that contains greater than 50% tuff is considered...
s in Pompeii-like eruptions. Dozens of other tuff cones dot the region, mainly on the eastern side of the complex.
Subfeatures
The following tuff cones stand out in the region:- Monte Becco
- Isola Bisentina
- La Dogana
- Monte Evangelista, 633 m (2,076.8 ft)
- Isola Martana
- Molino
- MontefiasconeMontefiasconeMontefiascone is a town and comune of the province of Viterbo, Italy, located on a hill on the southeast side of Lake Bolsena, 95 km north of GRA .-History:...
- Monte Montione
- ValentanoValentanothumb|250px|View of Valentano.Valentano is a town and comune of the province of Viterbo, in the Lazio region of central Italy. It is 33 km from the provincial capital, Viterbo.left|thumb|220px|Rocca Farnese in Valentano....
- Monte Pilato
- Monte Rosso
- Santa Luce
- Santa Maria di Sala
- Selva del Lamone
- Monte Semonte
- Monte Spinaio