1,720,985 research outputs found
The 2020–2022 paroxysmal episodes of the South-East Crater (Mt. Etna): insights into high-frequency eruptive activity from petrological monitoring
No full textA promising approach in isotope geochemistry: 87Sr/86Sr in human teeth and hair to study dietary and environmental effects
No full textIn recent years Sr isotope geochemistry has provided a huge contribution to environmental and
food traceability studies. This is possible because soils, plants and water are characterized by a
specific Sr isotopic signature (expressed through the 87Sr/86Sr ratio), which derives from the local
geological substratum which, in turn, depends on geological processes and on the age and initial
rubidium (Rb) content of the rocks, given that 87Rb decays to 87Sr over time. Since the relative
abundance of Sr isotopes does not change during the path through the food chain, the 87Sr/86Sr
ratio in human tissues reflects that of the “environment” in which people live and feed. In
particular, tooth enamel (which forms during the first years of life) does not exchange with
external Sr after mineralization. For this reason, its isotopic composition mostly reflects the 87
Sr/86Sr of the food intake that individuals used for energy, growth and maintaining the processes
of life, during their childhood.
In this work, the Sr isotopic characterization of deciduous human teeth and hair, water, soil, plants
and food was carried out. Donors are all born and currently residing in Campania (Southern Italy),
of different age and sex. The 87Sr/86Sr of deciduous teeth provides a direct link to the mother’s
milk, or to the artificial milk, which are the first foods for the newborn individuals, whereas the 87
Sr/86Sr of hair is directly related to the diet in adulthood. Moreover, the mother’s milk is in part
related to the local geological substratum and in part to the diet that has become no longer local,
but global. Despite adult individuals have different diets, the isotopic fingerprint of enamel teeth is
similar for all breastfeed children. Results from this study have scientific implications also for
human mobility studies
Strontium (Sr) and Neodymium (Nd) isotopic ratios of Mt. Etna bulk rocks 2020-2022 (BRET_ISO_2020_2022)
No full textThe database includes 87Sr/86Sr and 143Nd/144Nd isotopic ratios measured on bulk rocks of lava and pyroclasts sampled at Etna during 2020-2022 INGV-OE monitoring activity.The chemical treatment of the samples was carried out in the clean laboratory of the INGV-OV. Before chemical dissolution whole rock have been dissolved with high-purity HF–HNO3–HCl mixtures. Sr and Nd have been separated from the matrix through conventional ion-exchange chromatographic procedures, described in detail in Arienzo et al. (2013, 2014).Isotopic ratios have been measured by thermal ionization mass spectrometry (TIMS), using a Triton Plus® (Thermo Scientific) solid-source multicollector mass spectrometer in static mode. The blank was negligible considering the average Sr content of the samples; no determinations for Nd blanks was performed. Measured 87Sr/86Sr and 143Nd/144Nd ratios have been normalized for within-run isotopic fractionation to 88Sr/86Sr =8.375209 and 146Nd/144Nd =0.7219 respectively, using an exponential law for correction. During collection of isotopic data, replicate analyses of NIST-SRM 987 and JNdi-1 international reference standards have been performed to check for external reproducibility. During the period of analysis, the mean measured value (Goldstein et al., 2003) of 87Sr/86Sr 265 Sr for NIST-SRM 987 was 0.710242±0.000013 (2σ, where σ is the standard deviation of the values; n=48); that of 143Nd/144Nd for JNdi-1 was 0.512105±0.000007 (2σ, n=20) at Osservatorio Vesuviano. Sr and Nd isotope ratios of the samples have been normalized to the recommended values of NIST-SRM 987 and JNdi-1 (87Sr/86Sr 269 =0.710248; 143Nd/144Nd =0.512107; Zhang and Hu, 2020), respectively
Microplastic pollution in soil: a case-study from the Raffaele Viviani public park in Naples, Italy
Full text linkSubduction-related enrichment of the Phlegrean Volcanic District (Southern Italy) mantle source: new constraints on the characteristics of the sedimentary components
No full textThe Neapolitan volcanic area (Southern Italy), which includes the Phlegrean Volcanic District and the Somma–
Vesuvius complex, has been the site of intense Plio-Quaternary magmatic activity and has produced volcanic
rocks with a subduction-related geochemical and isotopic signature. High-Mg, K-basaltic lithic lava fragments
dispersed within hydromagmatic tuff of the Solchiaro eruption (Procida Island) provide constraints on the nature
and role of both the mantle source prior to enrichment and the subduction-related components. The geochemical
data (Nb/Yb, Nb/Y, Zr/Hf) indicate a pre-enrichment source similar to that of enriched MORB mantle. In order to
constrain the characteristics of subducted slab-derived components added to this mantle sector, new geochemical
and Sr–Nd-isotopic data have been acquired on meta-sediments and pillow lavas from Timpa delle Murge
ophiolites. These represent fragments of Tethyan oceanic crust (basalts and sediments) obducted during the
Apennine orogeny, and may be similar to sediments subducted during the closure of the Tethys Ocean. Based
on trace element compositions (e.g., Th/Nd, Nb/Th, Yb/Th and Ba/Th) and Nd-isotopic ratio, we hypothesize
the addition of several distinct subducted slab-derived components to the mantle wedge: partial melts from
shales and limestones, and aqueous fluids from shales, but the most important contribution is provided by
melts from pelitic sediments. Also, trace elements and Sr–Nd-isotopic ratios seem to rule out a significant role
for altered oceanic crust. Modeling based on variations of trace elements and isotopic ratios indicates that the
pre-subduction mantle source of the Phlegrean Volcanic District and Somma–Vesuvius was enriched by 2–4%
of subducted slab-derived components. This enrichment event might have stabilized amphibole and/or phlogopite
in the mantle source. 6% degree of partial melting of a phlogopite-bearing enriched source, occurring initially
in the garnet stability field and then in the spinel stability field can generate a melt with trace elements and Sr–
Nd-isotopic features matching those of high-Mg, K-basalts of Procida Island. Furthermore, 2% partial melting of
the same enriched source can reproduce the trace elements and isotopic features of the most primitive magmas of Somma–Vesuvius, subsequently modified by assimilation of continental crust during fractional crystallization processes at mid-lower depth. Combined trace element and Sr–Nd isotope modeling constrains the age of the enrichment event to 45 Ma ago, suggesting that the Plio-Quaternary magmatism of the Neapolitan area is postorogenic, and related to the subduction of oceanic crust belonging to the Tethys Ocean
The thermal regime of the Campi Flegrei magmatic system reconstructed through 3D numerical simulations
No full textWe illustrate a quantitative conductive/convective thermal model incorporating a wide range of geophysical, petrological, geological, geochemical and isotopical observations that constrain the thermal evolution and present state of the Campi Flegrei caldera (CFc) magmatic system. The proposed model has been computed on the basis of the current knowledge of: (1) the volcanic and magmatic history of the volcano over the last 44 ka, (2) its underlying crustal structure, and (3) the physical properties of the erupted magmas. 3D numerical simulations of heat conduction and convection within heterogeneous rock/magma materials with evolving heat sources and boundary conditions that simulate magma rise from a deep (≥ 8 km depth) to shallow (2–6 km) reservoirs, magma chamber formation, magma extrusion, caldera collapse, and intra-caldera hydrothermal convection, have been carried out. The evolution of the CFc magmatic system through time has been simulated through different steps related to its changes in terms of depth, location and size of magma reservoirs and their replenishment. The thermal modeling results show that both heat conduction and convection have played an important role in the CFc thermal evolution, although with different timing. The simulated present heat distribution is in agreement with the measured geothermal profiles (Agip, 1987), reproduces the thermal gradient peaks at the CFc margins in correspondence to the anomalies in surface gradients (Corrado et al., 1998), and suggests temperatures of 700 °C at depth of 4 km in the central portion of the caldera, in agreement with the estimated temperature for the brittle-ductile transition (Hill, 1992)
Unveiling geological identities: use of 87Sr/86Sr in food and beverages traceability, focusing on wines from Solopaca (Campania, Italy)
No full textResearch on food and beverages traceability, i.e., assessing their environmental origin, has
advanced significantly in recent years thanks in large part to strontium isotope geochemistry. The
unique Sr isotope signature (87Sr/86Sr) found in soils, plants, and waters makes the relation
between food/beverages and environment achievable. This signature is derived from the local
geological substratum and is influenced by age and initial concentration of rubidium in the rocks,
and to geological processes. The release of strontium ions from the bedrock due to weathering
processes, resulting from the interaction of circulating fluids with rocks, contributes to the
accumulation of Sr in waters and soils. Part of this Sr is bioavailable and its 87Sr/86Sr ratio can be
used as a valid tracer to identify the region of origin of wines. Considering an original 87Sr/86Sr ratio
in rocks and soil of a given locality, it is demonstrated that strontium is first absorbed by plant
roots, then by grapes, and finally by wine, without isotopic fractionation. As a result, the analysis of
the wine' Sr isotope ratio establishes a precise connection between the product and its geological
provenance, giving each wine a unique geofingerprint. This study aims to verify the strong
relationship between the product (wine) and its region by building on these foundations. The final
objective is to make the wine recognizable and distinguishable from comparable products so that
it can be protected from fraud and adulteration. Using the 87Sr/86Sr systematics, coupled with
traditional analyses such as thermal, XRD and FTIR analyses, 24 samples (8 soil samples, 8 grape
samples and 8 microvinification samples) from Solopaca (Campania, Italy) were investigated. In
order to provide a thorough Sr-isotopic characterization, soil samples were analyzed for both total
and bioavailable Sr fractions. This method improves the investigation of environmental processes
at every stage of the wine-making process
The magmatic feeding system of the Campi Flegrei caldera: architecture and temporal evolution
No full textTo develop a model of both the structure and evolution of the Campi Flegrei caldera (CFc) magmatic feeding system, geochronological, geochemical and Sr, Nd, Pb and B isotopic data of representative volcanic products of the past 15 ka have been combined with geophysical and melt inclusion literature data, structural setting and dynamics of the resurgent caldera.
According to previous petrological data, the CFc magmatic feeding system consists of a deep reservoir, in which mantle-derived K-basaltic parental magmas differentiate to shoshonite, latite and trachyte, through combined crustal contamination and fractional crystallization processes, and shallow reservoirs where the evolved magmas further differentiate and mingle/mix before eruptions. The Sr, Nd, Pb, and B isotope data allow recognition of three distinct magmatic components. One component is believed to be residual magma from the Neapolitan Yellow Tuff (NYT) caldera forming eruption. The NYT component (87Sr/86Sr of 0.70750–53, 143Nd/144Nd ratio of ca. 0.51246, 206Pb/204Pb of ca. 19.04 and δ11B of ca. –7.9‰), has been the most prevalent component over the past 15 ka being mixed, in most cases, with the other two components. One of these other components is best recognized in the Minopoli 2 magma, first erupted 10 ka ago. Minopoli 2 magma is shoshonitic in composition and is the most
enriched in radiogenic Sr (87Sr/86Sr of ca. 0.70860) and unradiogenic Nd and Pb (143Nd/144Nd ratio of ca. 0.51236,
206Pb/204Pb of ca. 18.90), and is characterised by δ11B value of ca. –7.32‰. The third component is trachytic in composition and has higher 206Pb/204Pb (ca. 19.08), lower 87Sr/86Sr (ca. 0.70726) and δ11B (−9.8‰) and higher 143Nd/144Nd (ca. 0.51250), with respect to the NYT component. This third component is best recognized in the Astroni 6 magma and did not appear until ca. 4 ka. The identified isotopically distinct magmatic components were erupted in different sectors of the CFc. During
both I (b14.9–9.5 ka) and II (8.6–8.2 ka) epochs of volcanic activity, magmas similar to the NYT component, and those resulting from mixing between Minopoli 2 and NYT components were erupted from vents located mostly on the marginal faults of the NYT caldera. During the III epoch (4.8–3.8 ka) magmas either similar to NYT, or resulting from mixing between Astroni 6 and NYT components were erupted from vents located along faults
bordering the La Starza resurgent block and, subordinately, the NYT caldera. Moreover, magmas resulting from mixing between Minopoli 2 and NYT components were erupted from vents located along NE–SW regional faults activated during caldera resurgence.
The inferred present structure of the feeding system is characterised by a deep reservoir, whose top is at about 8 km depth, that hosts shoshonitic–trachytic magmas. Remnants of the NYT magma reside at shallower depth in different sectors of the crust underlying CFc, and were sometimes intercepted by volatile-rich magmas of deep provenance during the three epochs of CFc volcanic activity
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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