Pre-eruptive magmatic processes triggering two different size eruptions occurred in recent volcanic activity of the Phlegraean district and their timescales

Pre-eruptive magmatic processes triggering two different size eruptions occurred in recent volcanic activity of the Phlegraean district and their timescale

Geochemical and Sr-Isotopic Study of Clinopyroxenes from Somma-Vesuvius Lavas: Inferences for Magmatic Processes and Eruptive Behavior

Somma-Vesuvius is one of the most dangerous active Italian volcanoes, due to the explosive character of its activity and because it is surrounded by an intensely urbanized area. For mitigating the volcanic risks, it is important to define how the Somma-Vesuvius magmatic system worked during the past activity and what processes took place. A continuous coring borehole drilled at Camaldoli della Torre, along the southern slopes of Somma-Vesuvius, allowed reconstructing its volcanic and magmatic history in a previous study. In this work, the wide range of chemical (Mg# = 92–69) and isotopic (87Sr/86Sr = 0.70781–0.70681) compositions, collected on single clinopyroxene crystals separated from selected lava flow units of the Camaldoli della Torre sequence, have been integrated with the already available bulk geochemical and Sr-isotopic data. The detected chemical and isotopic signatures and their variation through time allow us to better constrain the behavior of the volcano magmatic feeding system, highlighting that mixing and/or assimilation processes occurred before a significant change in the eruptive dynamics at Somma-Vesuvius during a period of polycyclic caldera formation, starting with the Pomici di Base Plinian eruption (ca. 22 ka)

Petrography and Mineral Chemistry of Monte Epomeo Green Tuff, Ischia Island, South Italy: Constraints for Identification of the Y-7 Tephrostratigraphic Marker in Distal Sequences of the Central Mediterranean

The 56 ka Monte Epomeo Green Tuff (MEGT) resulted from the largest volume explosive eruption from Ischia island (south Italy). Its tephra is one of the main stratigraphic markers of the central Mediterranean area. Despite its importance, a detailed characterisation of the petrography and mineral chemistry of MEGT is lacking. To fill this gap, we present detailed petrographic description and electron microprobe mineral chemistry data on samples collected on-land from the MEGT. Juvenile clasts include pumice, scoria, and obsidian fragments with porphyritic/glomeroporphyritic, vitrophyric, and fragmental textures. The porphyritic index is 13–40 vol.%, and phenocryst phases include alkali-feldspar, plagioclase, clinopyroxene, ferrian phlogopite, and titano-magnetite, in order of decreasing abundance; accessory phases include sphene, hydroxy-fluor-apatite, and rare edenite. Plagioclase varies from predominant andesine to subordinate oligoclase, whereas alkali-feldspar is more variable from sanidine to anorthoclase; quasi-pure sanidine commonly occurs as either rim or recrystallisation overgrowth of large phenocrysts due to hydrothermal alteration. Secondary minerals include veins and patches of carbonate minerals, Fe-Mn oxyhydroxides, clay minerals, and zeolites. Clinopyroxene is ferroan diopside (En45–29Fs7–27) and never reaches Na-rich compositions. This feature allows the discrimination of MEGT from aegirine-bearing, distal tephra layers erroneously attributed to MEGT, with implications for the areal distribution of Ischia explosive deposits

Mineral-Melt Equilibria and Geothermobarometry of Campi Flegrei Magmas: Inferences for Magma Storage Conditions

The eruptions of Campi Flegrei (Southern Italy), one of the most studied and dangerous active volcanic areas of the world, are fed by mildly potassic alkaline magmas, from shoshonite to trachyte and phonotrachyte. Petrological investigations carried out in past decades on Campi Flegrei rocks provide crucial information for understanding differentiation processes in its magmatic system. However, the compositional features of rocks are a palimpsest of many processes acting over timescales of 100–104 years, including crystal entrapment from multiple reservoirs with different magmatic histories. In this work, olivine, clinopyroxene and feldspar crystals from volcanic rocks related to the entire period of Campi Flegrei’s volcanic activity are checked for equilibrium with combined and possibly more rigorous tests than those commonly used in previous works (e.g., Fe–Mg exchange between either olivine or clinopyroxene and melt), with the aim of obtaining more robust geothermobarometric estimations for the magmas these products represent. We applied several combinations of equilibrium tests and geothermometric and geobarometric methods to a suite of rocks and related minerals spanning the period from ~59 ka to 1538 A.D. and compared the obtained results with the inferred magma storage conditions estimated in previous works through different methods. This mineral-chemistry investigation suggests that two prevalent sets of T–P (temperature–pressure) conditions, here referred to as “magmatic environments”, characterized the magma storage over the entire period of Campi Flegrei activity investigated here. These magmatic environments are ascribable to either mafic or differentiated magmas, stationing in deep and shallow reservoirs, respectively, which interacted frequently, mostly during the last 12 ka of activity. In fact, open-system magmatic processes (mixing/mingling, crustal contamination, CO2 flushing) hypothesized to have occurred before several Campi Flegrei eruptions could have removed earlier-grown crystals from their equilibrium melts. Moreover, our new results indicate that, in the case of complex systems such as Campi Flegrei’s, in which different pre-eruptive processes can modify the equilibrium composition of the crystals, one single geothermobarometric method offers little chance to constrain the magma storage conditions. Conversely, combined methods yield more robust results in agreement with estimates obtained in previous independent studies based on both petrological and geophysical methods

Mineral-Melt Equilibria and Geothermobarometry of Campi Flegrei Magmas: Inferences for Magma Storage Conditions

The eruptions of Campi Flegrei (Southern Italy), one of the most studied and dangerous active volcanic areas of the world, are fed by mildly potassic alkaline magmas, from shoshonite to trachyte and phonotrachyte. Petrological investigations carried out in past decades on Campi Flegrei rocks provide crucial information for understanding differentiation processes in its magmatic system. However, the compositional features of rocks are a palimpsest of many processes acting over timescales of 100–104 years, including crystal entrapment from multiple reservoirs with different magmatic histories. In this work, olivine, clinopyroxene and feldspar crystals from volcanic rocks related to the entire period of Campi Flegrei’s volcanic activity are checked for equilibrium with combined and possibly more rigorous tests than those commonly used in previous works (e.g., Fe–Mg exchange between either olivine or clinopyroxene and melt), with the aim of obtaining more robust geothermobarometric estimations for the magmas these products represent. We applied several combinations of equilibrium tests and geothermometric and geobarometric methods to a suite of rocks and related minerals spanning the period from ~59 ka to 1538 A.D. and compared the obtained results with the inferred magma storage conditions estimated in previous works through different methods. This mineral-chemistry investigation suggests that two prevalent sets of T–P (temperature–pressure) conditions, here referred to as “magmatic environments”, characterized the magma storage over the entire period of Campi Flegrei activity investigated here. These magmatic environments are ascribable to either mafic or differentiated magmas, stationing in deep and shallow reservoirs, respectively, which interacted frequently, mostly during the last 12 ka of activity. In fact, open-system magmatic processes (mixing/mingling, crustal contamination, CO2 flushing) hypothesized to have occurred before several Campi Flegrei eruptions could have removed earlier-grown crystals from their equilibrium melts. Moreover, our new results indicate that, in the case of complex systems such as Campi Flegrei’s, in which different pre-eruptive processes can modify the equilibrium composition of the crystals, one single geothermobarometric method offers little chance to constrain the magma storage conditions. Conversely, combined methods yield more robust results in agreement with estimates obtained in previous independent studies based on both petrological and geophysical methods

Coupled δ18O-δ17O and 87Sr/86Sr isotope compositions suggest a radiogenic and18O-enriched magma source for Neapolitan volcanoes (Southern Italy)

The origin of large variations in stable and radiogenic isotope compositions of magmas erupted from the Neapolitan volcanoes, including Somma-Vesuvius and Campi Flegrei (Southern Italy), has always been contentious. Indeed, the role and relative importance of sediment subduction versus crustal assimilation to explain the chemical and isotopic variations of the erupted magmas remain unclear. Isotopic disequilibrium between minerals and their host indicate that bulk rock analyses are incapable of constraining the isotopic composition of the source. Therefore, we use isotopic (87Sr/86Sr, 18O/16O and 17O/16O) data on separated minerals (feldspar, clinopyroxene and olivine phenocrysts) from pyroclastic successions and lava flows of the Neapolitan volcanic area (Phlegrean Volcanic District and Somma-Vesuvius complex) to better constrain magmatic oxygen and strontium isotope ratios. Magmatic values recalculated from δ18O of olivine and clinopyroxene phenocrysts range from typical mantle values of 5.2‰ to almost 9‰ relative to SMOW. These compositions are very different from those of typical mantle sources. In order to assess the degree of magma evolution from which these minerals formed, the Mg# of clinopyroxene and olivine were converted into host melt Mg#, resulting in the range 44 to 76. Simple assimilation of silicic crustal rocks is difficult to reconcile with the mafic nature of these estimated host magma compositions. This indicates that some mafic, mantle-derived magmas, having unusually heavy oxygen isotope (up to ~9‰) and high Sr isotope compositions (0.7050 to 0.7085), must exist. Crustal assimilation of carbonates can be excluded by the lack of a link between isotopes and major and trace element signatures. Assimilation of either Hercynian-like crust or altered pyroclastic rocks, however, cannot be ruled out completely. However, assimilation of partial melts from a Hercynian-like crust would have to be ~12% and ~21% to explain the heavy oxygen isotope values of Campi Flegrei and Somma-Vesuvius, respectively. Such degrees of assimilation are unlikely since the magmas are either too mafic or too alkaline to be consistent with such high proportion of crustal components. Other, less mafic Campi Flegrei, Somma-Vesuvius and Ischia magmas with more typical mantle oxygen isotopes, have been possibly generated in a mantle source affected by minor contamination by pelagic and carbonate sediments and subsequent assimilation of Hercynian-like crust. Sr-O mixing models indicate that such magmas were derived from a mantle source that was contaminated by up to 10% of a 1:1 mixture of pelagic and carbonate sediments. These findings together demonstrate the highly complex and varied magma sources in the Campania volcanic district. Triple oxygen isotope variations (Δ17O), based on measurements of both 18O/16O and 17O/16O ratios in potential assimilants are in agreement with these conclusions

Glucocorticoid sensitivity of T-cell lymphoblastic leukemia/lymphoma is associated with glucocorticoid receptor-mediated inhibition of Notch1 expression

[No abstract available

5FU/Oxaliplatin-induced Jagged1 cleavage counteracts apoptosis induction in colorectal cancer: a novel mechanism of intrinsic drug resistance

Colorectal cancer (CRC) is characterized by early metastasis, resistance to anti-cancer therapy, and high mortality rate. Despite considerable progress in the development of new treatment options that improved survival benefits in patients with early-stage or advanced CRC, many patients relapse due to the activation of intrinsic or acquired chemoresistance mechanisms. Recently, we reported novel findings about the role of Jagged1 in CRC tumors with Kras signatures. We showed that Jagged1 is a novel proteolytic target of Kras signaling, which induces Jagged1 processing/activation resulting in Jag1-ICD release, which favors tumor development in vivo, through a non-canonical mechanism. Herein, we demonstrate that OXP and 5FU cause a strong accumulation of Jag1-ICD oncogene, through ERK1/2 activation, unveiling a surviving subpopulation with an enforced Jag1-ICD expression, presenting the ability to counteract OXP/5FU-induced apoptosis. Remarkably, we also clarify the clinical ineffectiveness of gamma-secretase inhibitors (GSIs) in metastatic CRC (mCRC) patients. Indeed, we show that GSI compounds trigger Jag1-ICD release, which promotes cellular growth and EMT processes, functioning as tumor-promoting agents in CRC cells overexpressing Jagged1. We finally demonstrate that Jagged1 silencing in OXP- or 5FU-resistant subpopulations is enough to restore the sensitivity to chemotherapy, confirming that drug sensitivity/resistance is Jag1-ICD-dependent, suggesting Jagged1 as a molecular predictive marker for the outcome of chemotherapy

CD73 expression and pathologic response to neoadjuvant chemotherapy in triple negative breast cancer

The immune system plays a key role in tumor surveillance and escape. Recently, CD73 has been proposed as a prognostic biomarker associated with disease-free survival and overall survival in triple negative breast cancer (TNBC). In this study, we investigated the role of both CD73 expression and stromal tumor–infiltrating lymphocytes (TILs) in predicting the pathologic response of TNBC to neoadjuvant chemotherapy (NACT).We retrospectively analyzed CD73 immunohistochemical expression and stromal TILs on 61 consecutive biopsies from patients who received standard NACT. Twenty-three patients (38%) achieved pathologic complete response (pCR). TILs were present in the majority of biopsies (93%) with percentages ranging from 2 to 80%. High TILs (≥ 50%) were found in 30% of cases, and in this group, pCR was achieved in 76.5% of cases. Levels of TILs were associated with a better pathologic response only at univariate analysis (p = 0.037). The median value of CD73 expression on tumor cells was 40%. In 32 (52.5%) basal biopsies, CD73 expression was below or equal to median value (“low CD73”). A pCR was obtained in 53% of cases with “low CD73” and in 21% with high CD73, and this was statistically different both at univariate (p = 0.011) and multivariate (p = 0.014) analysis. Our results suggest that CD73 expression better predicts the response to NACT than TILs in TNBC. Characterization of both TILs and microenvironment could be a promising approach to personalize treatment