22 research outputs found
The submerged structure and stratal architecture of the Neapolitan Yellow Tuff (NYT) caldera, offshore the Campi Flegrei, (Eastern Tyrrhenian Margin): new insights from high resolution seismics and gravity core data
No full textThe Campi Flegrei is an active volcanic area defined by a
quasi-circular depression that covers some 200 km2 of the coastal
zone of SW Italy, a large part of which develops off the Naples
(Pozzuoli) Bay (Fig. 1). The area has been active at least since 60
ka BP ( Pappalardo et al., 1999), and is structurally dominated by a
caldera, 6 km in diameter, associated with the eruption of the
Neapolitan Yellow Tuff (NYT), a 40 km3 Dense Rock Equivalent
(DRE) ignimbrite (Scarpati et al., 1993) dated at ca 15 ka BP
(Deino et al., 2004), that covered the district now occupied by the
city of Naples, the Campi Flegrei and a large area of the
continental shelf off the Pozzuoli Bay.
The volcanological evolution of the NYT caldera as been long
described on the basis of outcrop and subsurface studies onland
(Rosi & Sbrana, 1987; Orsi et al., 1996, 2004 and references
therein; Di Vito et al., 1999; Perrotta et al., 2006; Fedele et al.,
2011), but its offshore morphology, detailed structure and recent
stratigraphic setting are still poorly understood.
In this study we integrate geological and geophysical data of
different resolution/penetration obtained from high-resolution
reflection seismic profiles (Sparker and Chirp source) with gravity
core and swath bathymetry to better constrain the shallow
structure, stratigraphic architecture and latest Quaternary to
Holocene evolution of the submerged sector of the NYT caldera
off the Pozzuoli Bay.
Our data clearly image, for the first time, the offshore geometry
of the NYT caldera ring-fault zone, as well as the style and timing
of volcano-tectonic deformation associated with the late stage
evolution of the NYT inner caldera resurgence. Our interpretation
suggests that since 15 ka the offshore sector of NYT inner caldera
underwent significant deformation and uplift (with minor
subsidence episodes) that occurred at almost the same rate as the
post-glacial sea-level rise. Particularly, the inner Pozzuoli Bay
started to deform soon after 15 ka BP, when sea-level rise was
initially faster than uplift. This caused a general increase of the
accommodation space that was progressively filled up by
volcaniclastic sediments. Since ca. 8 ka BP, along with the mid
Holocene decrease in the rate of the sea-level rise, the early NYT
resurgent structure was then uplifted up to the sea-level or even to
partial subaerial exposure. From ca. 8 to 5 ka BP two distinct
layers of volcaniclastic resediments, mostly represented by gravity
flow deposits, formed throughout the Bay. A significant post-
Roman (post 2 ka BP) subsidence phase of ca 10 m is then
recorded offshore Pozzuoli by the drowning of the infralittoral
prograding wedge below the present-day fair-weather wave base.
REFERENCES
Deino AL, Orsi G, de Vita S, Piochi M (2004) The age of the Neapolitan Yellow
Tuff caldera-forming eruption (Campi Flegrei caldera—Italy) assessed by
40Ar/39Ar dating method. J. Volcanol. Geotherm. Res. 133, 157–170.
Di Vito M., Isaia R., Orsi G., Southon J., de Vita S., D’Antonio M., Pappalardo
L., Piochi M., 1999. Volcanism and deformation since 12,000 years at the
Campi Flegrei caldera (Italy), J. Volcanol. Geotherm. Res. 91 (2-4), 221-246.
Fedele L., Insinga D.D., Calvert A.T., Morra V., Perrotta A., Scarpati C., 2011.
40Ar/39Ar dating of tuff vents in the Campi Flegrei caldera (southern Italy):
toward a new chronostratigraphic reconstruction of the Holocene volcanic
activity. Bull. Volcanol. 73, 1323-1336.
Orsi G, de Vita S, Di Vito M, 1996. The restless, resurgent Campi Flegrei nested
caldera (Italy): constraints on its evolution and configuration. J. Volcanol.
Geotherm. Res. 74, 179–214.
Orsi G., Di Vito M.A. Isaia R., 2004. Volcanic hazard assessment at the restless
Campi Flegrei caldera. Bull. Volcanol. 66, 514–530.
Pappalardo L., Civetta L., D’Antonio M., Deino A., Di Vito M., Orsi G.,
Carandente A., de Vita S., Isaia R. & Piochi M., 1999. Chemical and Srisotopical
evolution of the Phlegrean magmatic system before the Campanian
Ignimbrite and the Neapolitan Yellow Tuff eruptions J. Volcanol. Geotherm.
Res. 91, 141-166.
Perrotta A., Scarpati C., Luongo G., Morra V., 2006. The Campi Flegrei caldera
boundary in the city of Naples. In: De Vivo B (ed) Volcanism in the
Campania Plain: Vesuvius, Campi Flegrei and Ignimbrites. Elsevier,
Amsterdam, pp 85–96 (in the series Developments in Volcanology, 9)
Scarpati C., Cole P., & Perrotta A., 1993. The Neapolitan Yellow Tuff- A large
volume multiphase eruption from Campi Flegrei, Southern Italy. Bull.
Volcan. 55, 343-35
Large earthquakes along slow converging plate margins: Calabrian Arc paleoseismicity based on the submarine turbidite record
No full textThe Calabrian Arc subduction-rollback system hosts seismogenic faults capable of generating earth-
quakes exceeding magnitude 7. Since earthquakes are the result of long-term geodynamic processes, doc-
umenting seismic activity during a sufficiently long time interval is of fundamental importance for
hazard scenarios. Instrumental and historical data provide critical information on seismogenesis, but they
cover time periods shorter than the recurrence times of large earthquakes, especially in areas with low
deformation rates such as Calabria. If onshore paleoseismological studies are fundamental to compile
earthquake catalogs, they are sometime affected by the relatively poor continuity of sedimentation in
the subaerial environment.
In this study we applied the paleoseismological approach to the submarine environment to reconstruct
the record of high-energy sedimentary events triggered by seismic activity. We analyzed three gravity
cores collected in disconnected sedimentary basins to reconstruct resedimentation processes during
the Holocene, integrating inland information for a better assessment of tectonic activity and seismogen-
esis. Multiproxy analyses of the sedimentary record constrained by radiometric dating allowed recon-
structing event stratigraphy and linking resedimented deposits to specific earthquakes.
Onshore and offshore data allow to identify large-magnitude earthquakes in the central Calabrian Arc
subduction system during the Holocene, with inferred epicenters located either along normal faults
onshore and/or related to the slab dynamics. The turbidite record reveals 20 major events during the last
10 ka, with sources including crustal faults in Calabria (i.e. Lakes, Rossano and Cittanova faults). Analyses
of sediment samples and high-resolution seismic reflection images allowed identification of different
types of resedimented deposits during the last 30–50 ka. The basin-wide occurrence of three megatur-
bidites/homogenites suggests they are related to megatsunamis sourced by far field earthquakes along
the Hellenic Arc. Megaturbidites with a more limited spatial extent are interpreted as subduction-type
events in the Calabrian Arc, while thinner seismo-turbidites record the activity of crustal structures
including faults onshore. Results suggest a recurrence time of 2–3 ka for major Calabrian Arc events that
needs to be considered for a reliable hazard assessment in the Mediterranean region
The proximal marine record of the Marsili Seamount in the last 7ka (Southern Tyrrhenian Sea, Italy): Implications for the active processes in the Tyrrhenian Sea back-arc
No full textThe volcanism of back-arc basins resembles that of oceanic spreading centers, rifts, and, in vanishing stages, extensional arcs, depending on the amount and rate of the dynamic processes associated to the subduction. Marsili Seamount (MS) represents the axial ridge of the Southern Tyrrhenian Sea back-arc basin, which is connected to the slab roll-backing processes affecting the Calabrian Arc (Italy). The Southern Tyrrhenian Sea back-arc is characterized by a significant decline in the spreading rate with time (2.8-3.1. mm/a to less than 1.8. mm/a in the last 0.78-1. Ma). MS develops between about 1. Ma and 3. ka and mainly consists of lava flows erupted from central and fissural vents. The MS products belong to the calcalkaline association and range in composition from basalts to trachytes. We present new stratigraphic, geochronological, and geochemical data (glass shards and minerals) of tephra from a 2.35. m long gravity core (Marsili1 core) recovered on MS at 943. m b.s.l. We recognize five tephras [M1 (top of the core) to M5 (bottom)] represented by poorly to highly vesiculated ashes. The lowermost tephra M5 emplaced between ca. 7 and 26. ka B.P.; it represents the less evolved distal counterpart of the Unit D related to the Biancavilla-Montalto products of Mount Etna (Sicily). The M1 to M4 tephras emplaced between 2.1 and 7.2. ka B.P. and are related to strombolian-like submarine eruptions of NNE-SSW aligned MS vents. The composition of the M1-M4 glasses ranges from basaltic trachyandesites to andesites and trachytes. The M1 to M4 magmas mainly originated by crystal fractionation from a heterogeneous mantle source with varying LILE enrichments by subduction-related fluids. The degree of evolution of the MS magmas increases with decreasing time. The formation of vertically stacked magma storage zones at the crust/mantle interface and within MS is related to the vanishing Southern Tyrrhenian Sea opening, which implies the rapid (<. 1. Ma) evolution from a slow spreading back-arc setting to an arc system
The Neapolitan Yellow Tuff caldera offshore the Campi Flegrei: Stratal architecture and kinematic reconstruction during the last 15 ky
No full textIn 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.
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.
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
Age of submarine debris avalanches and tephrostratigraphy offshore Ischia Island, Tyrrhenian Sea, Italy
No full textWe present an "event stratigraphy" framework built for the last 23 cal ka marine record in the southern offshore of Ischia Island based on AMS (14)C dating and tephrostratigraphic analysis of 11 gravity cores. Two collapse events have been recovered in the record: a) the Ischia submarine debris avalanche/debris flow (DA/DF), dated between similar to 3 ka B.P. and 2.4 ka B.P. and possibly between 2.7 ka B.P. and 2.4 ka B.P. (event DF1); b) a former, pre-Holocene, DA/DF older than 23 cal ka B.P. (event DF2). The Ischia DA, with an estimated volume of 1.5 km(3), incorporates thousands of blocks that are still detectable on the sea-floor until 45-50 km far from the island. Our results indicate an age of emplacement younger than previously thought and support the hypothesis that a major catastrophic event occurred when the island was already inhabited by Greek settlers (i.e. after the 7th century BC). Three ash layers have been recognised in the post-DF1 avalanche sequence and correlated with Ischian eruptions occurred between Middle Ages and Roman times. Two tephras recovered in the pre-DF1 succession have been correlated with explosive activity occurred on Ischia and Procida islands from similar to 23 ka to similar to 17.5 ka B.P. The results presented here improve the chronostratigraphic reconstruction of the main eruptive and collapse events that affected Ischia volcano during Late Pleistocene-Holocene and their dispersal at sea The occurrence of at least two major collapsing events in the past 23 kyr confirms the close genetic relationship between gravity failures and Mt. Epomeo uplift. (C) 2010 Elsevier B.V. All rights reserved
Vertical motion, structural features and stratigraphic architecture of the Neapolitan Yellow Tuff (NYT) collapse caldera-resurgent dome system off the Pozzuoli Bay during the last 10 ky
No full textSeismic stratigraphic analysis of very high-resolution single channel reflection seismic profiles provided
insights into the last ~10 ka vertical deformation pattern in the submerged part of the Campi Flegrei resurgent
caldera, off the Pozzuoli Bay. The collapse of the central part of the Campi Flegrei is associated with the
eruption of the Neapolitan Yellow Tuff (NYT) at ~15 ka BP, and was followed by discrete phases of intracaldera
volcanic activity and resurgence (Di Vito et al., 1999). Only in recent years the southern part of the
caldera, presently submerged off the Pozzuoli Bay, has been explored using marine geophysical data (Sacchi
et al., 2014; Steinmann et al., 2016). Interpretation of the high-resolution seismic reflection dataset acquired
during the Cruise SEISTEC_2013, calibrated by marine gravity cores, allowed us to identify key horizons
between the 1538 AD M. Nuovo and the ~3.7 ka Averno eruptions. Chronostratigraphy of the older part of
the caldera fill was inferred through tentative correlation with significant eruptions known onland. Seismic
stratigraphic interpretation reveals the occurrence during the last ~10 ka of at least three generations of
Prograding Wedges (PW1-PW3) that were likely associated with corresponding periods of relative sea-level
stands, and of minor coastal terraces. Correction of the observed depth of each sea-level indicator for the paleobathymetric
estimate and for the glacio-hydro-isostatic sea-level change occurred since its formation, allowed
to reconstruct differential relative sea-level curves for the western, central and eastern sector of the submerged
part of the caldera. Preliminary results indicate that the periods of relative sea-level and accommodation space
stability that allowed the onset of Prograding Wedges were attained when uplift occurred at a rate comparable
to the rate of sea-level rise. These periods ostensibly correspond to known different phases of volcanic activity
and unrest, suggesting that not only volcanism but also ground deformation were temporally clustered.
Subsidence prevailed during periods of volcanic quiescence
A 4500 year record of palaeomagnetic secular variation and relative palaeointensity from the tyrrhenian sea
No full textA marine sediment core from the western Mediterranean provides a new high-resolution 4500 year record of palaeomagnetic secular variation and relative palaeointensity. In 2013, the 7.1 m C5 core was recovered from the Tyrrhenian Sea as part of the NextData climate data project. The coring site, 15 km offshore from the Volturno river mouth, is well located to record combined marine and terrestrial palaeoclimatic influences, and the fine-grained, rapidly deposited sediments are effective palaeomagnetic recorders. We investigate the palaeomagnetic field direction and strength recorded in the core, which provide a valuable high-resolution record of Holocene geomagnetic variation in the area. Using rock magnetic techniques, we constrain the magnetic mineralogy of the studied sediments and confirm their suitability for palaeomagnetic analysis. Palaeomagnetic declination and inclination records were determined by stepwise alternating-field demagnetization, and relative palaeointensity estimates were obtained based on normalization to anhysterestic and isothermal remanent magnetization and to magnetic susceptibility. The age of the core is well constrained with a tephra and biostratigraphic age model, and its magnetic records are compared with relevant core and model data for the region, demonstrating that our record is compatible with previous results from the area. An automated curve matching approach is applied to assess the compatibility of our data with the existing secular variation path for the Mediterranean area.Supplementary material: The code and data used to produce the results in this paper are available online at https://doi.org/10.5281/zenodo.115870
The role of choline metabolism in peripheral nervous system myelination
No full textMyelination of axons increases the efficiency of the nervous system by increasing the conductivity of the action potentials. Peripheral demyelinating diseases are prevalent disorders caused by impairments in Schwann cell myelination with no currently available cure. The objective of this thesis is to describe the role of choline metabolism in peripheral nervous system myelination. The myelin sheath is comprised of a large percentage of phospholipids and choline is the major precursor to many of its lipid components. The choline-phosphatidylcholine pathway generates phosphoinositide which important in lipid biosynthesis as well as intracellular signaling and endomembrane trafficking. The imbalance of phosphoinositide levels, particularly PI(3,5)P2, has been implicated in abnormal myelin formation. In fact, pathways regulating phosphoinositide levels are impaired in multiple peripheral demyelinating diseases underscoring the importance of understanding the role of choline metabolism in Schwann cell myelination. Choline also has regulatory effects on DNA and histone methylations, making it an important component for epigenetic modifications in Schwann cells. By gaining a better understanding of the molecular mechanisms that contribute to demyelinating disorders, specifically related to choline metabolism, we can develop effective therapeutic treatments.M.S.Includes bibliographical reference
Marine sediment cores database for the Mediterranean Basin: a tool for past climatic and environmental studies
No full textPaleoclimatic data are essential for fingerprinting the climate of the earth before the advent of modern recording instruments. They enable us to recognize past climatic events and predict future trends. Within this framework, a conceptual and logical model was drawn to physically implement a paleoclimatic database named WDB-Paleo that includes the paleoclimatic proxies data of marine sediment cores of the Mediterranean Basin. Twenty entities were defined to record four main categories of data: a) the features of oceanographic cruises and cores (metadata); b) the presence/absence of paleoclimatic proxies pulled from about 200 scientific papers; c) the quantitative analysis of planktonic and benthonic foraminifera, pollen, calcareous nannoplankton, magnetic susceptibility, stable isotopes, radionuclides values of about 14 cores recovered by Institute for Coastal Marine Environment (IAMC) of Italian National Research Council (CNR) in the framework of several past research projects; d) specific entities recording quantitative data on δ18O, AMS 14C (Accelerator Mass Spectrometry) and tephra layers available in scientific papers. Published data concerning paleoclimatic proxies in the Mediterranean Basin are recorded only for 400 out of 6000 cores retrieved in the area and they show a very irregular geographical distribution. Moreover, the data availability decreases when a constrained time interval is investigated or more than one proxy is required. We present three applications of WDB-Paleo for the Younger Dryas (YD) paleoclimatic event at Mediterranean scale and point out the potentiality of this tool for integrated stratigraphy studies
Tephrochronology of a ~70ka-long marine record in the Marsili Basin (southern Tyrrhenian Sea)
No full textInternational audienc
