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Boris
Behncke (1998)
Volcanism on the Hyblean Plateau (southeastern
Sicily)
during the past 230 Ma
Bollettino dell'Accademia Gioenia di Scienze
Naturali, Catania, volume 31 (no. 335), pages 39-50
Original title: Il vulcanesimo del Plateau
Ibleo (Sicilia sud-orientale) negli ultimi 230 Ma
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The Hyblean Plateau
(SE Sicily) has been the site of four major phases of volcanic activity
during the past 230 Ma, each of these phases occurring in different
tectonic conditions. The products of the first two phases (Upper Triassic
and Middle Jurassic) have only been encountered by deep drilling in
the Ragusa area, and consequently information about these volcanics
is limited. The products of the third phase of volcanism (Upper Cretacesou)
are prsent in outcrops and consist largely of submarine lavas and breccias.
Traces of eruptive centerc of this phase are present int he form of
a pronounced dike swarm at Capo Passero. Following the late Cretaceous
volcanism no eruptive activity occurred on the Hyblean Plateau for more
than 50 Ma, but in the late Miocene the fourth eruptive phase began;
this was to last until the early Pleistocene and consisted of five main
cycles. This phase of activity was characterized by highly variable
eruptive styles in a rapidly changing environment, resulting in a wide
range of facies. Eruptive activity took place intially below the sea
level, but some of the edifices grew above the sea level, creating volcanic
islands. During the Upper Pliocene and Lower Pleistocene there were
complex interactions between sea-level fluctuations and tectonic uplift
of the northern margin of the Hyblean Plateau. All volcanic activity
on the Plateau ceased during the Lower Pleistocene, but continued in
the area adjacent to the north, progressing across the Catania Plain
to the Etnean zone, where it is continuing to the present. Even though
located in a geodynamic setting different from that of the Hyblean Plateau,
Etna may be considered but the latest chapter in the long saga of Hyblean
volcanism.
The total volume of Hyblean volcanics exceeds 3500 km3, but
this figure must be considered in connection with the fact that all
eruptive episodes were of very brief duration (years to centuries) and
correspondingly the eruption rates were high during these events.
Keywords: Volcanism, Hyblean Plateau, Sicily,
Eruptive phases, Submarine eruptions, Volcanic islands
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