The Phlegraean Fields are a large volcanic area situated to the west of Naples, Italy. It was declared a regional park in 2003. Lying mostly underwater, the area of the caldera comprises 24 craters and volcanic edifices. Hydrothermal activity can be observed at Lucrino, Agnano and the town of Pozzuoli. There are also effusive gaseous manifestations in the Solfatara crater, which is known as the mythological home of the Roman god of fire, Vulcan. The area also features bradyseismic phenomena, which are most evident at the Macellum of Pozzuoli which in the 18th century was misidentified as a Temple of Serapis, as geologists puzzled over bands of boreholes (Gastrochaenolites) left by marine Lithophaga molluscs on three standing marble columns, showing that the level of the site in relation to sea level had varied.
This area is monitored by the Vesuvius Observatory.
Three geological phases or periods are recognised and distinguished.
The First Phlegraean Period. It is thought that the eruption of the Archiflegreo volcano occurred about 39.28 ± 0.11 ka. erupting about 200km3 of magma (500km3 bulk volume) to produce the Campanian Ignimbrite. "The dating of the Campanian Ignimbrite (CI) eruption to ~37,000 calendar years B.P. draws attention to the coincidence of this volcanic catastrophe and the suite of coeval, Late Pleistocene biocultural changes that occurred within and outside the Mediterranean region. These included the Middle to Upper Paleolithic cultural transition and the replacement of Neanderthal populations by anatomically modern Homo sapiens, a subject of sustained debate. No less than 150 km3 of magma were extruded in the CI eruption, the signal of which can be detected in Greenland ice cores. As widespread discontinuities in archaeological sequences are observed at or following the CI event, a significant interference with ongoing human processes in Mediterranean Europe is hypothesized." New research led by Liubov Vitalievna Golovanova and Vladimir Borisovich Doronichev of the ANO Laboratory of Prehistory in St. Petersburg, Russia, supports the hypothesis that these eruptions drove Neanderthals to extinction and cleared the way for modern humans to thrive in Europe and Asia. The area is characterised by banks of piperno and pipernoid grey tuff at Camaldoli hill, like in the northern and western ridge of Mount Cumae; other referable deep products are those found at Monte di Procida, recognizable in the cliffs of its coast.
The Second Phlegraean Period. Between the 35,000-10,500 years ago, it is characterized by the yellow tuff that constitutes the rests of an immense underwater volcano (having a diameter of ca. 15km and Pozzuoli to its center) Approximately 12,000 years ago the last major eruption occurred, forming a smaller caldera inside the main one, centered on the town of Pozzuoli. This event produced the Neapolitan yellow tuff, referring to the characteristic yellow rocks there.
The Third Phlegraean Period. Dated between 8,000 – 500 years ago, it is characterized by white pozzolana, the material that forms the majority of volcanos in Flegrei Fields. Broadly speaking, it can be said there was an initial activity to the south-west in the zone of Bacoli and Baiae (10,000-8,000 years ago); an intermediate activity in an area centred between Pozzuoli, Spaccata Mountain and Agnano (8,000-3,900 years ago); and a more recent activity, moved towards the west to form Lake Avernus and Monte Nuovo (New Mountain) (3,800–500 years ago).
Volcanic deposit indicating possible eruption dated Ar at 315, 205, 157 and 18.0 kya
The caldera, which now is essentially at ground level, is accessible on foot. It contains a large number of fumaroles, from which steam can be seen issuing, and over 150 pools of boiling mud at last count. Several subsidiary cones and tuff craters lie within the caldera. One of these craters is filled by Lake Avernus. In 1538, an eight-day eruption in the area deposited enough material to create a new hill, Monte Nuovo. It has risen about 2m from ground level since 1970. It is a volcano capable of producing VEI 7 eruptions, as large as that of Tambora in 1815. At present, the Campi Flegrei area comprises the Naples districts of Agnano and Fuorigrotta, the area of Pozzuoli, Bacoli, Monte di Procida, Quarto, the Phlegrean Islands (Ischia, Procida and Vivara).
A 2009 journal article stated that inflation of the caldera centre in the vicinity of Pozzuoli might presage an eruptive event within decades. In 2012 the International Continental Scientific Drilling Program planned to drill 3.5 km (2.2 miles) below the earth's surface near Pompeii intending to monitor the massive molten rock chamber below in order to provide early warning of any eruption. Local scientists are worried that such drilling itself could initiate an eruption or earthquake. In 2010 the Naples city council had prevented the drilling project. Programme scientists said the drilling was no different from industrial drilling in the area. The newly elected mayor allowed the project to go forward. A Reuters article emphasized that the area could produce a "super volcano" that might kill millions.Antonio Denti, "Super volcano", global danger, lurks near Pompeii, Reuters, August 3, 2012.
Italian wine, both red and white, under the Campi Flegrei DOC appellation comes from this area. Grapes destined for DOC production must be harvested up to a maximum yield of 12 tonnes/hectare for red grape varieties and 13 tonnes/ha for white grape varieties. The finished wines need to be fermented to a minimum alcohol level of 11.5% for reds and 10.5% for whites. While most Campi Flegrei wines are blends, varietal wines can be made from individual varieties provided the variety used comprises at least 90% of the blend and the wine is fermented to at least 12% alcohol for reds and 11% for whites.
Red Campi Flegrei is a blend of 50-70% Piedirosso, 10-30% Aglianico and/or Sciascinoso and up to 10% of other local (both red and white) grape varieties. The whites are composed of 50-70% Falanghina, 10-30% Biancolella and/or Coda di Volpe with up to 30% of other local white grape varieties.
Campi Flegrei has had strategic and cultural importance.
The area was known to the Greeks, who had a colony nearby at Cumae.The beach of Miliscola, in Bacoli, was the Roman military academy headquarters.Lake Avernus was believed to be the entrance to the underworld, and is portrayed as such in the Aeneid of Virgil. During the civil war between Octavian and Antony, Agrippa tried to turn the lake into a military port, the Portus Julius.Cumae was the first Greek colony on the mainland of Italy and is perhaps most famous as the seat of the Cumaean Sibyl.Baiae, now lying underwater, was a fashionable coastal resort and was the site of summer villas of Julius Caesar, Nero, and Hadrian (who died there).A Flavian Amphitheatre (Amphitheatrum Flavium), the third largest Italian amphitheatre after the Colosseum and the Capuan Amphitheatre.The Via Appia passed through the comune of Quarto, entirely built on an extinguished crater.The Cave of Dogs -- a famous tourist attraction during the early modern period -- is on the eastern side of the Fields.Europe's youngest mountain, Monte Nuovo is here. The WWF oasis lies beside the enormous Astroni crater.The tombs of Agrippina the Elder and Scipio Africanus are here as well.At Baiae, a Bacoli district the most ancient hot spring complex was built for the richest Romans. It included the largest ancient dome in the world before the construction of the Roman Pantheon.Patrick Moore used to cite Campi Flegrei as an example of why the impact craters on the Moon must be of volcanic origin, which was thought to be the case until the 1960s.A Campanian ignimbrite super-eruption around 40,000 years ago has been hypothesised as having contributed to the demise of the Neanderthal, based on evidence from Mezmaiskaya cave in the Caucasus Mountains of southern Russia