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New insights into quaternary explosive volcanic activity of Pantelleria Island (Southern Italy)
No full textReply to the comment on the article “40Ar/39Ar dating of tuff vents in the Campi Flegrei caldera (southern Italy): toward a new chronostratigraphic reconstruction of the Holocene volcanic activity” by Isaia et al.
No full textLate Holocene sedimentary changes in shallow water settings: The case of the Sele River offshore in the Salerno Gulf (south-eastern Tyrrhenian Sea, Italy)
No full textA complementary data set consisting of sedimentological, petrophysical, geochronologic and seismo-stratigraphic analysis was used to detect the sedimentary changes in the inner shelf record in a mostly stable region, over the last 3 ky cal BP, that is since the sea level attained its present day position. This study has been carried out within the VULCOST project on the Salerno Gulf (south-eastern Tyrrhenian Sea, Italy), to learn more about the impact of minor morpho-climatic changes and anthropogenic disturbances on the shelf sedimentary record. Some decimeter-thick sandy beds deposited on the inner shelf, off the Sele river mouth, in the time span corresponding to the Little Ice Age (LIA), despite the fact that, at the time, the coastline at that time was farther inland with respect to its present day position. Since the beginning of the 20th century, mainly fine grained sediment settled, possibly owing to the restoration of mild climatic conditions, changes in the rivers' regime and land-use. The analysis of the marine cores, collected off the coast, also reveals a litho-stratigraphic mismatch among coeval intervals, possibly driven by the different response of the catchments to the morpho-climatic variations. High resolution seismic data shows that the sediment bypass area, shaped by wave action, is much deeper than the estimated limit, if computed on the base of fair-weather wave length and sedimentologic analysis. Indeed, toplap terminations of reflectors are recognizable as deep as 25 m in the southern sector of the Gulf and suggest an intense reworking of the seabed over long periods, much deeper than the outer limit of the beach. This evidence is also supported by the state of pyroclastic layers in the core record, which proves sediment reworking in the marine setting, down to 24 m of depth. The high resolution sedimentologic and stratigraphic reconstructions point to a non linear relation between depth, distance from the coast and sand deposition over the time. This suggests a complex picture of coastal dynamics within the same basin, with a remarkable outcome regarding the wave-cut terraces as proxies of sea level stands. © 2012 Springer-Verlag
Major and trace element characterization of tephra layers offshore Pantelleria Island: new insights into the last 200 ka volcanic activity on land and implications for the Mediterranean tephrochronology.
No full textA detailed tephrochronological study was carried out on the deep-sea core collected from Site 963A in the Sicily Channel during ODP Leg 160. The chronology of the succession is provided by an age–depth model based on isotope stratigraphy and quantitative eco-biostratigraphy. Major, trace and rare earth element content was obtained on single glass grains through electron probe micro-analysis and laser ablation–inductively coupled plasma mass spectrometry techniques from six well-preserved tephra layers, characterized by a discrete thickness found along the succession. These deposits were correlated with the volcanic activity of Pantelleria and dated at 42.5, 127.5, 128.1, 129.1, 188.7 and 197.7 ka. This detailed chemical characterization of the studied deposits aims to provide a valuable
reference database for scientists working on both proximal and distal products erupted at Pantelleria island during the Late Pleistocene. This study, moreover, offers the opportunity to better identify Pantelleria-related marker tephras within the tephrochronological framework of the central and eastern Mediterranean area
Seismic expression of the shallow structure of The Neapolitan Yellow Tuff (NYT) caldera offshore the Campi Flegrei
Full text linkIn this study we integrate high-resolution swath bathymetry, single-channel reflection seismic data and gravity core
data, to provide new insights into the shallow structure and latest Quaternary to Holocene evolution of the submerged
sector of the Neapolitan Yellow Tuff (NYT) caldera (Campi Flegrei) in the Pozzuoli Bay. The new data allow for a
reconstruction of the offshore geometry of the NYT caldera collapse – ring fault system, along with the style and timing
of deformation of the inner caldera resurgence.
Our interpretation shows that the NYT eruption (~15 ka BP) was associated with a caldera collapse bounded by an
inward-dipping ring fault system. The ring fault system consists in a 1-2 km wide fault zone that encircles an inner
caldera region ~ 5 km in diameter and is often marked by the occurrence of pore fluids ascending through the fault
zone, up to the seafloor, particularly in the western sector of the bay. A shallow magmatic intrusion along the ring fault
zone was also detected offshore Bagnoli in the eastern part of the Pozzuoli Bay (Sacchi et al., 2014).
Following the NYT eruption, the inner caldera region underwent significant deformation and resurgence with a
maximum cumulative uplift of the offshore structure in the order of 180 m. The net uplift rate of the caldera resurgent
dome was ~ 9 - 12 mm/year during the period 15.0 – 6.6 ka BP. The style of deformation of the resurgent structure can
be described in terms of a broad doming, accompanied by subordinate brittle deformation, mostly concentrated in a
small apical graben at the summit of the resurgent dome (Cole et al., 2005).
Chronostratigraphic calibration of seismic profiles obtained by three tephra layers cored in the Pozzuoli Bay
indicates 5 to 25 m of post-Roman differential subsidence and tilting towards ESE of the inner caldera resurgence, as
recorded by the drowning of the infralittoral prograding wedge below the present-day storm wave base
The palaeoclimatic and palaeoceanographic history of the Gulf of Taranto (Mediterranean Sea) in the last 15 ky
No full textA multidisciplinary study, which includes micropaleontology, sedimentology and geochemistry, was carried out
on the TEA-C6 core, raised in the Gulf of Taranto (north-western Ionian Sea). The chronological framework was
yielded by tephrostratigraphy combined with ecostratigraphy and AMS 14C dating. New results allowed surface
and bottom conditions in the Gulf of Taranto during the last 15 ky to be reconstructed, thus providing a detailed
and age-constrained paleoclimate and paleocological record for this sector of the Mediterranean Sea. The quantitative
record of past sea surface temperatures (SST) was obtained by means of Compositional Data Analysis
(CoDA) methods applied to planktonic foraminifera assemblages. High-resolution analyses allowed the Sapropel
S1 event to be characterised at centennial-scale resolution. The main interval of the sapropel S1, here dated between
10.2calka and 7.8calka, is preceded and followed by transition phases spanning several centuries and
prevailing anoxic bottom conditions are punctuated by several episodes of partial oxygen recovery. The S1a interval
corresponds to high summer SST, whereas an SST drop of about 2.5° took place towards the end of the
S1b interval. New tephrochronological data record the signature of eruptive events from Italian volcanoes which
were not documented on land up to date
The Late Pleistocene to Holocene tephra record of ND14Q site (southern Adriatic Sea). Traceability and preservation of Neapolitan explosive products in the marine realm
No full textA tephrochronological investigation was carried out at site ND14Q (1013 m of water depth), located in the southern Adriatic Sea, offshore the Gargano promontory. It was drilled in the frame of The NextData Project (www.nextdataproject.it, 2011-2013), focused on paleoclimate research. To obtain a composite and well preserved deep marine record, three cores were raised at the study site. Twelve primary cryptotephra and one tephra were analysed in terms of major-element content and correlated with a total of sixteen eruptive events. The studied materials display K-alkaline and subalkaline features pointing to a correlation with the Somma-Vesuvius, Campi Flegrei and Lipari Island (Aeolian Arc) volcanic activity occurred during the Late Pleistocene-Holocene. In detail, major marker tephra of the central Mediterranean have been recognized, among which the Phlegraean Neapolitan Yellow Tuff (ca. 15 ka), Pomici Principali (ca. 12 ka BP) and Astroni-Agnano-Monte Spina (ca. 4.2 ka - 4.4 ka BP) eruptions and, for the first time in this area, the Vesuvian 79 CE event. The very well preserved Mercato (ca. 9 ka BP) and Fiumebianco-Gabellotto (ca. 8.4 ka BP) cryptotephra have also been found in the sapropel S1 interval of the succession, which definitely records the last ca. 22 kyr (Pomici di Base tephra). A number of other Plinian and sub-Plinian events also occur and the availability of multiple cores provided new insights into their temporal relation such as between AP2 and Astroni 6 eruptions. The identification of tephra sourced by well-dated volcanic events, along with several AMS 14C age results, allowed an accurate chronological framework for the composite tephrostratigraphic record, thus providing accurate ages for those deposits with an uncertain correlative event. In addition, stratigraphic evidences in the core replicates at ND14Q site showed that several intervening factors affect preservation and traceability of cryptotephra deposits in the marine realm posing main critical issues on volcanological and paleoclimate research
The Neapolitan Yellow Tuff tephra in the stratigraphic architecture of the Gulf of Gaeta shelf, eastern Tyrrhenian margin
No full text40Ar/39Ar dating of tuff vents in the Campi Flegrei caldera (southern Italy): toward a new chronostratigraphic reconstruction of the Holocene volcanic activity
No full textAbstract. The Campi Flegrei hosts numerous monogenetic
vents inferred to be younger than the 15 ka Neapolitan Yellow Tuff. Sanidine crystals from the three young Campi Flegrei vents of Fondi di Baia, Bacoli and Nisida were dated using 40Ar/39Ar geochronology. These vents, together with several other young edifices, occur roughly along the inner border of the Campi Flegrei caldera, suggesting that the volcanic conduits are controlled by caldera-bounding faults. Plateau ages of ∼9.6 ka (Fondi di Baia), ∼8.6 ka (Bacoli) and ∼3.9 ka (Nisida) indicate eruptive activity during intervals previously interpreted as quiescent. A critical revision, involving calendar age correction of
literature 14C data and available 40Ar/39Ar age data, is presented. A new reference chronostratigraphic framework for Holocene Phlegrean activity, which significantly differs from the previously adopted ones, is proposed. This has important implications for understanding the Campi Flegrei eruptive history and, ultimately, for the evaluation of related volcanic risk and hazard, for which the inferred history of its recent activity is generally taken into account
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