178 research outputs found

    Corrigendum. Maars to calderas: end-members on a spectrum of explosive volcanic depressions

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    A corrigendum on Maars to calderas: end-members on a spectrum of explosive volcanic depressions by Palladino, D. M., Valentine, G. A., Sottili, G., and Taddeucci, J. (2015). Front. Earth Sci. 3:36. doi: 10.3389/feart.2015.00036 Reason for Corrigendum: In the original article (Palladino et al., 2015), there was an error in Figure 1. The vertical axis of the qualitative plot reported erroneously “ratio of juvenile to lithic materials in deposits outside of depression”. The correct wording is as follows: “ratio of juvenile to total (i.e., juvenile+lithic) materials in deposits outside of depression”. In fact, as it was reported correctly in the text, the amount of juvenilematerial (i.e., scoria or pumice) deposited ouside the different types of explosive volcanic depressions increases from zero (i.e., no juvenile, all lithic products), as is the case of hydrothermal (phreatic) explosion craters, to become largely dominant over the lithic component in the case of ash flow deposits associated with large overpressure collapse calderas. The corrected Figure 1 appears below. The authors apologize for this error and state that this does not change the scientific conclusions of the article in any way

    Micronucleus induction by low doses of X-rays in Vicia faba root tips

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    Studies on the micronucleus test in Vicia faba root tips (VM test) were carried out in order to estimate the effects at low doses of X-rays (1, 2, 4, 8 and 12 R). The control value of micronucleus frequency is about 0.44/1000 cells. The dose where the micronucleus frequency is twice that of the control was estimated at 1.384 R. There was a linear kinetic dose response for the low-dose range studied here

    Assessing the volcanic hazard for Rome. 40Ar/39Ar and In-SAR constraints on the most recent eruptive activity and present-day uplift at Colli Albani Volcanic District

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    We present new 40Ar/39Ar data which allow us to refine the recurrence time for the most recent eruptive activity occurred at Colli Albani Volcanic District (CAVD) and constrain its geographic area. Time elapsed since the last eruption (36 kyr) overruns the recurrence time (31 kyr) in the last 100 kyr. New interferometric synthetic aperture radar data, covering the years 1993–2010, reveal ongoing inflation with maximum uplift rates (>2 mm/yr) in the area hosting the most recent (<200 ka) vents, suggesting that the observed uplift might be caused by magma injection within the youngest plumbing system. Finally, we frame the present deformation within the structural pattern of the area of Rome, characterized by 50 m of regional uplift since 200 ka and by geologic evidence for a recent (<2000 years) switch of the local stress-field, highlighting that the precursors of a new phase of volcanic activity are likely occurring at the CAVD

    Major explosive activity in the Monti Sabatini Volcanic District(central Italy) over the 800-390ka interval: Geochronological-geochemical overview and tephrostratigraphic implications

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    A review of the existing chronological, stratigraphic and chemo-petrologic data of the major eruptive units from the early phase of activity (800-390ka) in the Monti Sabatini Volcanic District (MSVD), belonging to the ultra-potassic magmatic region of central Italy, is presented along with new radioisotopic age determinations and geochemical analyses. Through the combined use of electron microprobe glass compositions, selected trace-element compositions, and single-crystal 40Ar/39Ar age determinations, we provide a new chrono- and chemo-stratigraphic classification of the products emplaced in the 800-390ka time interval. Besides giving insights on the petrologic evolution of the Roman Comagmatic Region, the large dataset provides fundamental information that is applicable to tephrostratigraphic studies in the wide region encompassing the Tyrrhenian Sea margin to the Adriatic Sea basin. Distal tephras from this volcanic activity also act as important geochronologic markers for the coastal sedimentary successions deposited in response to glacio-eustatic fluctuations, as well as for successions in the Quaternary tectonic basins of the Central and Southern Apennines. An innovative approach based on the use of discrimination diagrams of Zr/Y vs Nb/Y ratios for fingerprinting altered volcanic rocks - recently developed and successfully employed in archaeometric studies - is here combined to the glass compositions for classifying the MSVD deposits and tested on two distal tephra layers, showing its potentiality for tephrostratigraphic correlation. © 2014 Elsevier Ltd

    Biomarkers in wound drainage fluids of head and neck squamous cell carcinoma patients receiving neck dissection: A pilot study

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    Aim: In a pilot prospective study, we aimed to test the feasibility and report on the preliminary results on the expression of molecular biomarkers in wound drainage fluids (WDFs) of operated head and neck squamous cell carcinoma (HNSCC) patients. Material and methods: Nineteen patients undergoing primary tumor resection with en-block neck dissection were enrolled. In postoperative days 1–3, the expression of several biomarkers in WDFs was measured using enzyme-linked immunosorbent assay (ELISA) kits and correlated with clinical and histopathologic features. Results: The expression of stromal cell-derived factor 1 (CXCL-12) was significantly increased in WDFs in presence of lymph node metastases, extranodal extension (ENE), and in case of close resection margins. In addition, Osteopontin expression was significantly increased in presence of ENE, whereas transforming growth factor beta (TGF-β) detection was significantly reduced. At multivariate analysis, CXCL-2 levels in both day 1 and 3 post-surgery were the only factor which retained significance in the prediction of close surgical margins (p = 0.028 and 0.025 for day 1 and day 3, respectively). Both CXCL-2 and Ostepontin assays were significantly correlated with ENE (p = 0.018 and 0.035 for day 1; 0.052 and 0.025 for day 3, respectively) whereas TGF- β expression was significant at day 1 only (p = 0.038) Conclusions: Our pilot study showed that WDFs could qualify as a potential source of relevant postoperative information. Further studies are needed to confirm the prognostic impact of CXCL-12, Osteopontin and TGF-β expressed in WDFs on the personalized management of HNSCC

    Central Mediterranean tephrochronology between 313 and 366 ka. New insights from the Fucino paleolake sediment succession

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    Thirty-two tephra layers were identified in the time-interval 313–366 ka (Marine Isotope Stages 9–10) of the Quaternary lacustrine succession of the Fucino Basin, central Italy. Twenty-seven of these tephra layers yielded suitable geochemical material to explore their volcanic origins. Investigations also included the acquisition of geochemical data of some relevant, chronologically compatible proximal units from Italian volcanoes. The record contains tephra from some well known eruptions and eruptive sequences of Roman and Roccamonfina volcanoes, such as the Magliano Romano Plinian Fall, the Orvieto–Bagnoregio Ignimbrite, the Lower White Trachytic Tuff and the Brown Leucitic Tuff. In addition, the record documents eruptions currently undescribed in proximal (i.e. near-vent) sections, suggesting a more complex history of the major eruptions of the Colli Albani, Sabatini, Vulsini and Roccamonfinavolcanoes between 313 and 366 ka. Six of the investigated tephra layers were directly dated by single-crystal-fusion 40Ar/39Ar dating, providing the basis for a Bayesian age–depth model and a reassessment of the chronologies for both already known and dated eruptive units and for so far undated eruptions. The results provide a significant contribution for improving knowledge on the peri-Tyrrhenian explosive activity as well as for extending the Mediterranean tephrostratigraphical framework, which was previously based on limited proximal and distal archives for that time interval

    Physical stratigraphy and geotechnical properties controlling the local seismic response in explosive volcanic settings: the Stracciacappa maar (central Italy)

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    Nowadays, policies addressed to prevention and mitigation of seismic risk need a consolidated methodology finalised to the assessment of local seismic response in explosive volcanic settings. The quantitative reconstruction of the subsoil model provides a key instrument to understand how the geometry and the internal architecture of outcropping and buried geological units have influence on the propagation of seismic waves. On this regard, we present a multidisciplinary approach in the test area of the Stracciacappa maar (Sabatini Volcanic District, central Italy), with the aim to reconstruct its physical stratigraphy and to discuss how subsoil heterogeneities control the 1D and 2D local seismic response in such a volcanic setting. We first introduce a new multidisciplinary dataset, including geological (fieldwork and log from a 45-m-thick continuous coring borehole), geophysical (electrical resistivity tomographies, single station noise measurements, and 2D passive seismic arrays), and geotechnical (simple shear tests performed on undisturbed samples) approaches. Then, we reconstruct the subsoil model for the Stracciacappa maar in terms of vertical setting and distribution of its mechanical lithotypes, which we investigate for 1D and 2D finite element site response analyses through the application of two different seismic scenarios: a volcanic event and a tectonic event. The numerical modelling documents a significant ground motion amplification (in the 1–1.5 Hz range) revealed for both seismic scenarios, with a maximum within the centre of the maar. The ground motion amplification is related to both 1D and 2D phenomena including lithological heterogeneity within the upper part of the maar section and interaction of direct S-waves with Rayleigh waves generated at edges of the most superficial lithotypes. Finally, we use these insights to associate the expected distribution of ground motion amplification with the physical stratigraphy of an explosive volcanic setting, with insights for seismic microzonation studies and local seismic response assessment in populated environments

    Reconstructing the Late Pleistocene – Anthropocene interaction between the neotectonic and archaeological landscape evolution in the Apennines (La Sassa cave, Italy)

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    Caves are one of the most conservative environments on Earth, where archaeological, anthropological,climatic and tectonic data can be well-preserved. Here, we present the results of a multidisciplinarymethod that allowed us to recognize, for thefirst time in this area, the interaction between Late Pleis-tocene to Anthropocene neotectonic and archaeological evolutionary stages of a cave of the Apennines(La Sassa cave), that encompass also its surroundings (Volsci Range and Pontina Plain). Both structuraland 3D survey highlighted a step-wise shape of the cave due to normal fault steps that allowed thelocalized formation of concretions also enveloping archaeological layers. Sixteen14C ages on fauna andhuman bonds and thousands of archaeologicalfinds provided chronological constraints of faulting in theLate Pleistocene and possibly also after the Middle Bronze Age. In the frame of a region that was notpreviously recognized as tectonically active, the structural evidence is relevant for understanding thespeleogenesis of the cave from the Late Pleistocene and its human occupation. Burial and ritual activitiesin the cave from the Copper Age to the Middle Bronze Age have been recognized with implications onpossible settlement pattern schemes with the La Sassa cave as a“persistent place”in the prehistorichuman landscape. The analyses of the ceramic style in a regional framework also suggests the presenceof a cultural boundary near La Sassa, which becomes highly osmotic just after the beginning of theMiddle Bronze Age. The La Sassafindings provide as well implications for the seismic hazard assessmentin a region inhabited by about 0.4 million peopl
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