Actualité volcanique, Articles de fond sur étude de volcan, tectonique, récits et photos de voyage
The Tyrrhenian basin forms the deepest part of the Mediterranean Sea , with the Tyrrhenian pit to a depth of 3,800 meters. It was caused by a geological process involving African and Eurasian tectonic plates , which began there 10 million years and is contemporary of the formation of the Apennine Mountains .
Volcanism of the Tirreno Sea (green)
- Volcanoes of the Aeolian arc (red) - Doc. amicidelleterra
Besides the Marsili submarine volcano , other major volcanoes emerge from the central Tyrrhenian plain : the Vavilov , the Magnaghi and many lesser known , including the Palinuro, the Glaucus ,
the Eolo, the Sisyphus , and the Enarete .
Vavilov , Marsili and Magnaghi were discovered in 1950 and
named after the geologists have revealed.
The submarine volcanoes of the Tirreno Sea ( 1-9 ) and the Sicily Channel
( 10-13 ) - Doc. Protezione Civile - Rischio vulcanico / Volcani Sottomarini
.
The
Vavilov emerges from the seabed at 3,600 meters and rises until it reaches 684 meters below the sea level. This large building, 30 km x 15 km and 350-400
km3 , can be divided into two parts , according to four dives of the submersible Cyana :
- From its base at 1500 m depth , it consists of thick layers of basaltic
flows.
- Above 1500m depth , smaller flows
emitted by the central volcano, and others through vents aligned NS . Lavas forming the
upper parts are dated from 100,000 to 400,000 years.
Other observations suggest a phase of subaerial terminal
construction, followed by a subsidence of the basin to more than 500 m. depth in the Quaternary.
Vavilov lavas are very close to OIB - Oceanic Island Basalts . Vavilov appears as an independent
structure of the oceanic crust that supports , and does not represent a dorsal-related oceanic accretion.
The Palinuro seamount emerges from nearly 3,000 m depth up to
73 m. under the sea surface, on a fault system oriented EO . It is topped by a shoe-horse caldera. Lavas of the top are dated from the
Pleistocene. Petrochemicals is roughly
identical to that of the Aeolian arc , and interpreted as generated by the subduction of the eastern Mediterranean under the Calabrian arc .
A layer of marine ash , radiocarbon dated to 9,990 years ago , is similar chemically and stratigraphically to two other layers of ash on land south of Italy, and correlated to the activity of
Palinuro seamount ( Siani et al . 2004)
Position on submarine volcanoes of the
Tirreno Sea compared to the Aeolian arc (in red)
The submarine volcanoes
Eolo, Enarete and Sisyphus are aligned NW-SE , west of the Aeolian arc and are high of a thousand meters. Eolo is distinguished from others by a flat top.
Alcione volcano and
its twin, the Lametini are located between the alignment Palinuro - Glabro and the Aeolian arc . These volcanoes have a conical shape, and the surrounding fund exceeds one thousand
meters.
Sources:
- Protezione Civile – Rischio vulcanico / Volcani sottomarini - link
- Structural framework of the Tyrrhenian Sea unveiled by seafloor
morphology - Struttura del Mar Tirreno svelata dalla morfologia del fondale - M.P.Marini & F.Gamberi
- Geomagnetism and age study of Tyrhenian seamounts - O.Faggion & al.
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