Publication Date:
2021-01-14
Description:
The Marsili Seamount (MS) is an about 3200 m high volcanic complex measuring 70 × 30 km with the top at
~500 m b.s.l. MS is interpreted as the ridge of the 2 Ma old Marsili back-arc basin belonging to the Calabrian
Arc–Ionian Sea subduction system(Southern Tyrrhenian Sea, Italy). Previous studies indicate that theMS activity
developed between 1 and 0.1 Ma through effusions of lava flows. Here, new stratigraphic, textural, geochemical,
and 14C geochronological data from a 95 cm long gravity core (COR02) recovered at 839 m bsl in theMS central
sector are presented. COR02 contains mud and two tephras consisting of 98 to 100 area% of volcanic ash. The
thickness of the upper tephra (TEPH01) is 15 cm, and that of the lower tephra (TEPH02) is 60 cm. The tephras
have poor to moderate sorting, loose to partly welded levels, and erosive contacts, which imply a short distance
source of the pyroclastics. 14C dating on fossils above and below TEPH01 gives an age of 3 ka BP. Calculations of
the sedimentation rates from the mud sediments above and between the tephras suggest that a formation of
TEPH02 at 5 ka BP MS ashes has a high-K calcalkaline affinity with 53 wt.% b SiO2 b 68 wt.%, and their composition
overlaps that of the MS lava flows. The trace element pattern is consistent with fractional crystallization
from a common, OIB-like basalt. The source area of ashes is the central sector of MS and not a subaerial volcano
of the Campanian and/or Aeolian Quaternary volcanic districts. Submarine, explosive eruptions occurred atMS in
historical times: this is the first evidence of explosive volcanic activity at a significant (500–800 m bsl) water
depth in the Mediterranean Sea.MS is still active, the monitoring and an evaluation of the different types of hazards
are highly recommended.
Description:
Published
Description:
764-774
Description:
2IT. Laboratori sperimentali e analitici
Description:
JCR Journal
Description:
restricted
Keywords:
Submarine active volcanism
;
04. Solid Earth::04.04. Geology::04.04.05. Mineralogy and petrology
Repository Name:
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Type:
article
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