Search results for " Petr"
showing 10 items of 1574 documents
Terminal Strombolian activity at Etna’s central craters during summer 2012: The most CO<sub>2</sub>-rich volcanic gas ever recorded at Mo…
2016
Exploring the explosive-effusive transition using permanent ultraviolet cameras
2017
Understanding the mechanisms that cause effusive eruptions is the key to mitigating their associated hazard. Here, we combine results from permanent ultra-violet (UV) cameras, and from other geophysical observations (seismic very long period, thermal, and infrasonic activity), to characterize volcanic SO2 flux regime in the period prior, during, and after Stromboli's August-November 2014 effusive eruption. We show that, in the two months prior to effusion onset, the SO2 flux levels are two times average level. We explain this anomalously high SO2 regime as primarily determined by venting of rapidly rising, pressurized SO2-rich gas pockets, produced by strombolian explosions being more frequ…
Halogens in volcanic systems
2009
The transport, degassing and atmospheric release of halogens from active volcanism on Earth have been the 12 focus of increasing interest over the last few decades, and have recently been the subject of the 1st workshop 13 on “Halogens in volcanic systems and their environmental impacts” that was held in December of 2007 at 14 Yosemite Lodge in Yosemite National Park, California. As an introduction to this Chemical Geology special 15 issue, collecting contributions from many of the participants at the workshop, we review here recent 16 advances in this field, including experimental and theoretical investigations of halogen behaviour in volcanic 17 and related magmatic systems. We discuss pr…
Low-P hydrous phase equilibria of a pantellerite melt: constraints on pre-eruptive conditions of recent felsic explosive volcanism at Pantelleria.
2007
Recent felsic explosive magmatism at Pantelleria island: an experimental study
2009
Os, Sr, Nd, Pb, O isotope and trace element data from the Ferrar flood basalts, antarctica: evidence for an enriched subcontinental lithospheric sour…
1996
Os, Sr, Nd, Pb and O isotopes and trace element data are reported for basaltic andesite and andesite whole rocks and, in part, for selected mineral separates from the Jurassic Ferrar flood basalt province. Radiogenic Sr (> 0.709), unradiogenic Nd (εNd= −3 to −5), and radiogenic Pb isotopes, as well as low Nb/La ratios of 0.4 – 0.6 and Nb/La ratios between 0.45 and 0.6 are found for all rocks including our most primitive sample (Mg# = 71.9). This indicates involvement of either continental crust or enriched lithospheric mantle in magma genesis. 187Re/188Os correlates strongly with 187Os/188Os, with an age of 172 ± 5 Ma, in agreement with published Arsingle bondAr data. Initial 187Os/188Os of…
Petrology and geochemistry of peri-Mediterranean carbonatite magmatism: case studies from Fuerteventura (Canary Islands) and Mt. Vulture volcano (sou…
2023
Carbonatites are rare magmatic rocks of great scientific and economic importance, and carbonatite magmatism is mainly associated with intraplate continental tectonic settings, with some rare occurrences in oceanic contexts. Despite their importance, many aspects of carbonatite petrogenesis and evolution processes remain still poorly constrained. In order to further constrain the mantle source and the storage system of carbonatite magmas, Fuerteventura (Canary Islands) was taken as a representative case study of oceanic carbonatites, while Mt. Vulture (southern Italy) was taken as a representative case study of intra-continental carbonatites, with a two-fold aim: to understand (i) the role o…
Source Mechanisms of Laboratory Earthquakes During Fault Nucleation and Formation
2021
Identifying deformation and pre-failure mechanisms preceding faulting is key for fault mechanics and for interpreting precursors to fault rupture. This study presents the results of a new and robust derivation of first motion polarity focal mechanism solutions (FMS) applied to acoustic emission (AE). FMS are solved using a least squares minimization of the fit between projected polarity measurements and the deviatoric stress field induced by dilatational (T-type), shearing (S-type), and compressional (C-type) sources. 4 × 10 cm cylindrical samples of Alzo Granite (AG, porosity <1%) and Darley Dale Sandstone (DDS, porosity ≈14%) underwent conventional triaxial tests in order to investigat…
El mito de orfeo y euridice en los origenes del melodrama
2019
En el nacimiento de la ópera (el melodrama) el tema elegido de manera mayoritaria fue el del mito de Orfeo, el semidiós cantor porque con este personaje no se rompía la verosimilitud al representar obras totalmente cantadas. Aunque su presencia en el género operístico de los orígenes se debe también a otros factores importantes. La complejidad del personaje, de su historia y características que han hecho de Orfeo un personaje literario, cuya presencia destaca en diferentes obras de autores de todos los tiempos. En la literatura italiana, la influencia de Virgilio, que nos presenta a Orfeo en las Geórgicas, y de Ovidio y sus Metamorfosis fue determinante, pero además el personaje de Orfeo es…
Bimodal sill emplacement from an inhomogeneous source: a case study of olivine-gabbronorite and diabase with Ni-Cu sulphides in a sill within Permian…
2009
A small outcrop of mafic rocks, located between the Permian-Triassic sediments of the Cenozoic tectonic unit of the Maghrebian chain in Western Sicily, is an olistolith made up of olivine gabbronorite within diabase. Textures, microprobe analyses, and major and trace element geochemistry confirm the co-genetic nature of the various rocks: the gabbronorite is the result of olivine and orthopyroxene accumulation, with interstitial clinopyroxene and plagioclase, in a framework of a gabbrodioritic diabase. At least two stages of magmatic crystallisation during ascent in the continental crust are described, on the basis of reconstructed conditions of T, P and XH2O. The primitive magma was recons…