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  • 04. Solid Earth::04.04. Geology::04.04.05. Mineralogy and petrology  (3)
  • AGU  (1)
  • Dipartimento di Scienze della Terra e Geologico-Ambientali of the University of Bologna (Italy), in collaboration with GeoSed, the Italian Association for Sedimentary Geology  (1)
  • Nature Publishing Group
  • 2010-2014  (3)
  • 1985-1989
Collection
Keywords
Publisher
Years
Year
  • 1
    facet.materialart.
    Unknown
    Rapid differentiation in a sill-like magma reservoir: a case study from the campi flegrei caldera (2012)
    Nature Publishing Group
    Details
    Publication Date: 2017-04-04
    Description: In recent decades, geophysical investigations have detected wide magma reservoirs beneath quiescent calderas. However, the discovery of partially melted horizons inside the crust is not sufficient to put constraints on capability of reservoirs to supply cataclysmic eruptions, which strictly depends on the chemical-physical properties of magmas (composition, viscosity, gas content etc.), and thus on their differentiation histories. In this study, by using geochemical, isotopic and textural records of rocks erupted from the high-risk Campi Flegrei caldera, we show that the alkaline magmas have evolved toward a critical state of explosive behaviour over a time span shorter than the repose time of most volcanic systems and that these magmas have risen rapidly toward the surface. Moreover, similar results on the depth and timescale of magma storage were previously obtained for the neighbouring Somma-Vesuvius volcano. This consistency suggests that there might be a unique long-lived magma pool beneath the whole Neapolitan area.
    Description: Published
    Description: article 712
    Description: 2.3. TTC - Laboratori di chimica e fisica delle rocce
    Description: 3.5. Geologia e storia dei vulcani ed evoluzione dei magmi
    Description: 3.6. Fisica del vulcanismo
    Description: 4.3. TTC - Scenari di pericolosità vulcanica
    Description: N/A or not JCR
    Description: open
    Keywords: magma ; campi flegrei caldera ; 04. Solid Earth::04.04. Geology::04.04.05. Mineralogy and petrology ; 04. Solid Earth::04.08. Volcanology::04.08.03. Magmas ; 04. Solid Earth::04.08. Volcanology::04.08.05. Volcanic rocks ; 04. Solid Earth::04.08. Volcanology::04.08.08. Volcanic risk
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
    Location Call Number Expected Availability
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    PAPER (OA)
  • 2
    facet.materialart.
    Unknown
    Magnetic properties of sedimentary greigite (Fe3S4): an update (2011)
    AGU
    Details
    Publication Date: 2017-04-04
    Description: Accepted for publication in Reviews of Geophysics. Copyright (2010) American Geophysical Union
    Description: Greigite (Fe3S4) is an authigenic ferrimagnetic mineral that grows as a precursor to pyrite during early diagenetic sedimentary sulfate reduction. It can also grow at any time when dissolved iron and sulfide are available during diagenesis. Greigite is important in paleomagnetic, environmental, biological, biogeochemical, tectonic, and industrial processes. Much recent progress has been made in understanding its magnetic properties. Greigite is an inverse spinel and a collinear ferrimagnet with antiferromagnetic coupling between iron in octahedral and tetrahedral sites. The crystallographic c-axis is the easy axis of magnetization, with magnetic properties dominated by magnetocrystalline anisotropy. Robust empirical estimates of the saturation magnetization, anisotropy constant, and exchange constant for greigite have been obtained recently for the first time, and the first robust estimate of the low-field magnetic susceptibility is reported here. The Curie temperature of greigite remains unknown, but must exceed 350°C. Greigite lacks a low-temperature magnetic transition. Based on preliminary micromagnetic modeling, the size range for stable single domain behavior is 17-200 nm for cubic crystals and 17-500 nm for octahedral crystals. Gradual variation in magnetic properties is observed through the pseudo-single domain size range. We systematically document the known magnetic properties of greigite (at high, ambient and low temperatures, and with alternating and direct fields) and illustrate how grain size variations affect magnetic properties. Recognition of this range of magnetic properties will aid identification and constrain interpretation of magnetic signals carried by greigite, which is increasingly proving to be environmentally important and responsible for complex paleomagnetic records, including widespread remagnetizations.
    Description: In press
    Description: 2.2. Laboratorio di paleomagnetismo
    Description: JCR Journal
    Description: open
    Keywords: greigite ; 04. Solid Earth::04.04. Geology::04.04.05. Mineralogy and petrology ; 04. Solid Earth::04.04. Geology::04.04.08. Sediments: dating, processes, transport ; 04. Solid Earth::04.05. Geomagnetism::04.05.06. Paleomagnetism ; 04. Solid Earth::04.05. Geomagnetism::04.05.07. Rock magnetism ; 04. Solid Earth::04.05. Geomagnetism::04.05.09. Environmental magnetism
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 3
    facet.materialart.
    Unknown
    Evidence for different processes of magma evolution in El Tatio volcanic region (22°16' to 22°30' S, Central Volcanic Zones, Andes) (2011)
    Dipartimento di Scienze della Terra e Geologico-Ambientali of the University of Bologna (Italy), in collaboration with GeoSed, the Italian Association for Sedimentary Geology
    Details
    Publication Date: 2021-12-06
    Description: We report new petrographic and geochemical data on volcanic rocks erupted over the last 9 Ma ca. within El Tatio volcanic region (Western Cordillera – CVZ). They originated from compound volcanism alternating composite volcano activities, lava domes formation and minor low-mild explosive eruptions, whereas ignimbrite-like deposits outcropping in the region originated from external caldera system (Altiplano Puna Volcanic Complex). The volcanics – mostly erupted in the last 1 Ma - have composition ranging between calcalkaline (CA) to high-K calcalkaline (HKCA) basaltic andesite to rhyolite, but most of them are andesites and dacites. Petrographic features of the studied rocks can be frequently related to strong disequilibrium conditions in the crystallizing system: deeply resorbed and rounded mineral phases, reaction rims, skeletal habits, large ranges of mineral compositions with direct and reverse zoning, oxidations and uralitizations phenomena are observed. Most of these crystal disequilibrium features may be explained by convective self-mixing processes in magma reservoirs cooling from above and characterized by mafic magma batch at the base as a probable heat source, with minor role for magma mixing between compositionally different magmas. On the other hand, the high crystallization degree of the rocks together with evidence provided by geochemical data suggest that FC of recurrent mineral assemblages (plag.±pyrox±hornbl±bt) in closed magma chamber must be considered the most significant differentiation process for several volcanic apparatus forming El Tatio area. Although the FC holds a leading role, the correlation of geochemical and few available isotopic data also point to AFC processes as further important evolutionary mechanism. Isotopic trends and patterns of incompatible elements (i.e LILE enrichment, LILE/HFSE ratios) mirror the interaction of magmas with crustal contaminants occurring both in the mantle wedge (material transported via subduction) and during the ascent/ ponding of the parental magmas along the thick crust beneath the CVZ. In other words, starting from already modified parental magmas, further modification of variable type affected the magmas at higher level. Finally, we suggest that the plumbing systems (high level magma reservoirs) hosting the magmas of El Tatio region were characterized by multistage evolutionary processes consistent both with open- and closed-system regimes.
    Description: Published
    Description: 31-58
    Description: 3.5. Geologia e storia dei vulcani ed evoluzione dei magmi
    Description: N/A or not JCR
    Description: open
    Keywords: Andes ; Tatio ; magma evolution ; disequilibrium textures ; 04. Solid Earth::04.04. Geology::04.04.05. Mineralogy and petrology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
    Location Call Number Expected Availability
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