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  • 1
    Publication Date: 2022-04-22
    Description: We describe the diagnostic lithological and chemical features of distal tephras from major MiddleLate Pleistocene (560e36 ka) explosive eruptions of the Colli Albani volcanic district, central Italy. In particular, we explore the time-dependent variability of the Sr and Nd isotope compositions as a tool for recognising and pinpointing individual Colli Albani tephra in distal settings. The distal tephras investigated are in lacustrine and fluvial sediments of central Apennine intermountain basins located 70 kme100 km east of Colli Albani. The recognition of the Colli Albani tephras is essentially based on the K-foiditic composition of their glass, which, within the Italian volcanological framework, is a distinctive character of the Colli Albani pyroclasts. In detail, these tephras are attributed to the following eruptive units: Tufo Pisolitico di Trigoria (561 2 ka); Tufo del PalatinoeTufo di Bagni Albule (530 2/527 2 ka), Tufo di Bagni AlbuleePozzolane Rosse air-fall sequence (517 1 to 500 3 ka), Pozzolane Rosse (457 4 ka), Villa Senni (365 4 ka), and Albano 5e7 (41 7 to 36 1 ka). These correlations are supported by 40Ar/39Ar dating of the distal tephras correlated to the Pozzolane Rosse (457.4 1.7 ka), Villa Senni (365 2 ka) and Albano 5e7 (41 9 ka) and by 87Sr/86Sr measured on clinopyroxene crystals and fresh glassy scoria from distal Colli Albani tephras that range from w0.711 to w0.709. These ratios are similar to those that characterise the individual proximal correlative units, and show the same decreasing trend over time. In contrast, the 143Nd/144Nd ratios for proximal and distal bulk samples and clinopyroxene increase from w0.51212 to w0.51215 from the oldest to the youngest tephra deposit. In summary, the study of Sr and Nd isotope compositions that is here applied on products from the Colli Albani volcanic district is a powerful, complementary tool to the more traditional tephrostratigraphic methods (e.g., componentry and electron microprobe analysis) for fingerprinting of distal tephras over a large region of the central Mediterranean, and over a large time interval, such as from 560 ka to 36 ka.
    Description: Published
    Description: 190-206
    Description: 2V. Struttura e sistema di alimentazione dei vulcani
    Description: 3V. Proprietà chimico-fisiche dei magmi e dei prodotti vulcanici
    Description: 4V. Processi pre-eruttivi
    Description: JCR Journal
    Keywords: Ultra-potassic tephra markers ; Roman Comagmatic Province ; Major elements glass compositions ; Isotopic 87Sr/86Sr and 143Nd/144Nd
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 2
    Publication Date: 2022-02-28
    Description: Leucititic rocks, K-foiditic in composition are volumetrically important in the Colli Albani (also known as Alban Hills) volcanic district (Central Italy) especially during the most explosive phases of activity (〉200 km3). The Colli Albani tephra in distal (〉500 km) deposits indicates that K-foiditic magma chambers fed large explosive eruptions (i.e., tens of km3 of pyroclastic rocks). Major oxides, trace elements and Raman spectra were measured on the glasses and minerals occurring in the K-foiditic scoria clasts of the ~530 kyr-old Tufo del Palatino, erupted in the Colli Albani volcanic district. The Colli Albani pre-eruptive magmatic system is characterized by the aH2O 〈 1 and high CO2 activ- ity in the melt, as testified by the CO3 in the clinopyroxene melt inclusions, by the early crystallization of CO3-bearing apatite and by the high CO2 activity in the free volatile phase that led to crystallization of calcium carbonate in the scoria clast vesicles. The K-foiditic magmas plot on the Cpx + Lc + melt divariant surface of the Ol-Cpx-Lc-Mel- H2O-CO2, P ≥ 0.2 GPa and T ≤ 1100 °C. The assimilation of cold carbonate by hot magmas is an important open- system process allowing the establishment of aH20 〈 1 condition in the volatile-rich, Colli Albani magma chambers where the stability fields of the olivine and phlogopite are reduced in favor of clinopyroxene and leucite. Trace ele- ment modelling indicates large amount of carbonate assimilation (~12.4 wt%) involved in the differentiation process that origins the K-foiditic magmas starting from a K-rich, phonotephritic parental magma. The large amount of as- similate carbonate is consistent with the peculiar distribution of the latent heat across the crystallization interval of the phonotephritic parental magma. The isenthalpic assimilation process is very efficient in the phonotephritic magma because the crystallization of clinopyroxene and leucite in equilibrium with a K-foiditic melt proceeds over a relatively large temperature interval (〉200 °C) and the K-foiditic melt shows low viscosity (104Pa·s at 1000 °C). Actually, the low melt viscosity, that increases the growth rate, and the large temperature interval of crys- tallization are intrinsic factors that increase the release of the latent heat of crystallization from the phonotephritic parental magma. Extrinsic factors enhancing the assimilation process efficiency are the thickness (〉4 km) and the depth (down to 5–7 km) of the carbonate substrate in the Colli Albani volcanic district.
    Description: Published
    Description: 106239
    Description: 3V. Proprietà chimico-fisiche dei magmi e dei prodotti vulcanici
    Description: JCR Journal
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 3
    Publication Date: 2022-02-28
    Description: Glacial-interglacial variations in ice volume and sea level are essential components of the Pleistocene global climate evolution. Deciphering the timing of change of these key climate parameters with respect to the insolation forcing is central to understanding the processes controlling glacial terminations. Here we exploit the sensitivity of the Paleo Tiber River (central Italy) to sea-level forced changes in the base level and the frequent occurrence of datable tephra layers in its sedimentary successions to reconstruct the timing of the relative sea-level (RSL) change between 450 and 403 ka, i.e., across the glacial termination (T-V) that marks the transition between Marine Isotope Stage (MIS) 12 and MIS 11. The analysis hinges on new stratigraphic data, tephra geochemical fingerprinting, and 40Ar/39Ar dating from a fluvial section that represents the inland counterpart of the near mouth, coastal aggradational succes- sions of the San Paolo Formation (SPF). Tephra correlation indicates that the morpho-stratigraphic record of the inland section is as sensitive to the sea-level change as its coastal counterparts, which makes it ideal to complement previous RSL reconstructions from the Tiber River catchment basin, thereby providing a more detailed picture of the sea-level history across T-V. Combined sedimentological and morphological proxies of the composed inland-coastal SPF record document the occurrence of two phases of relatively rapid sea-level rise, here interpreted as meltwater pulse (MWP) events. The earlier MWP occurred between ~450 and ~445 ka and matches a relatively minor episode of the sea-level rise documented in an existing RSL record, while the younger MWP at ~430 ka corresponds to the high amplitude sea-level rise that marks T-V. We find that both MWPs coincide with episodes of ice-rafted debris deposition in the North Atlantic (Heinrich-like events) and with attendant Southern Hemi- sphere warming, plausibly associated with the bipolar seesaw.
    Description: Published
    Description: 106976
    Description: 5A. Ricerche polari e paleoclima
    Description: JCR Journal
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 4
    Publication Date: 2022-02-24
    Description: Dissolution of clinopyroxene (cpx) in a K-basaltic melt from the Campi Flegrei Volcanic District (Italy) has been investigated through dissolution and dissolution-crystallization experiments at pressure of 0.8 GPa, superliquidus temperature of 1350 ◦C, and dwell times between 0.5 and 1 h. The obtained dissolution rates range from 7.9⋅10− 6 cm s− 1 to 6.1⋅10− 6 cm s− 1 as a function of dwell time. In the dissolution-crystallization experiment (1300 ◦C; 0.8 GPa; 2 h), the formation of overgrowth rims accompanied by new cpx crystals suggests that the injection of recharge magmas in basaltic reservoir may lead to inverse or oscillatory zonation. The interaction between cpx and K-basaltic melt at ~1570 ◦C was studied by in situ radiography using synchrotron radiation combined with the Paris-Edinburgh press. This resulted in cpx resorption to occur depending on the temperature conditions with respect to the liquidus temperature of the cpx (TcpxL). The calculated cpx dissolution rates are ~5⋅10− 3 cm s− 1 at T ≤ TcpxL and ~ 3⋅10− 2 cm s− 1 at T ≥ TcpxL. The role of crystal dissolution in the estimation of magma residence times has been also tested for a natural magmatic system by interpolating the dissolution rates (~10− 5–10− 6 cm s− 1) with the textural data of cpx phenocrysts from the Agnano-Monte Spina pyroclastic deposit at Campi Flegrei caldera (Campanian region, Italy). Results from calculations indicate that the time required for partial or complete resorption of phenocrysts varies from ~0.5 to ~40 h, and that the effect of crystal dissolution may be relevant to estimate magma residence times whether signifcant dissolution occurs during magma mixing processes.
    Description: Published
    Description: 120533
    Description: 3V. Proprietà chimico-fisiche dei magmi e dei prodotti vulcanici
    Description: JCR Journal
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 5
    Publication Date: 2021-12-15
    Description: Here, we report on the Quaternary Volsci Volcanic Field (VVF, central Italy). In light of new 40Ar/39Ar geochronological data and compositional characterization of juvenile eruptive products, we refine the history of VVF activity, and outline the implications on the pre-eruptive magma system and the continental subduction processes involved. Different from the nearby volcanic districts of the Roman and Campanian Provinces, the VVF was characterized by small-volume (0.01–0.1 km3) eruptions from a network of monogenetic centers (mostly tuff rings and scoria cones, with subordinate lava occurrences), clustered along high-angle faults of lithospheric depth. Leucite-bearing, high-K (HKS) magmas (for which we report for the first time the phlogopite phenocryst compositions) mostly fed the early phase of activity (∼761–539 ka), then primitive, plagioclase-bearing (KS) magmas appeared during the climactic phase (∼424–349 ka), partially overlapping with HKS ones, and then prevailed during the late phase of activity (∼300–231 ka). The fast ascent of primitive magma batches is typical of a tectonically controlled volcanic field, where the very low magma flux is a passive byproduct of regional tectonic strain. We suggest that the dominant compressive stress field acting at depth was accompanied by an extensional regime in the upper crust, associated with the gravity spreading of the Apennine chain, allowing the fast ascent of magma from the mantle source with limited stationing in shallow reservoirs.
    Description: Published
    Description: 689–718
    Description: 1V. Storia eruttiva
    Description: JCR Journal
    Keywords: Quaternary volcanism ; 40Ar/39Ar geochronology ; Tyrrhenian Sea margin ; Central Italy
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 6
    Publication Date: 2021-12-14
    Description: We present the study of a composite, yet continuous sedimentary succession covering the time interval spanning 2.6-0.36 Ma in the intramontane basin of Anagni (central Italy) through a dedicated borecore, field surveys, and the review of previous data at the three palaeontological and archaeological sites of Colle Marino, Coste San Giacomo and Fontana Ranuccio. By combining the magneto- and chronostratigraphic data with sedimentologic and biostratigraphic analysis, we describe the palaeogeographic and tectonic evolution of this region during this entire interval. In this time frame, starting from 0.8 Ma, the progressive shallowing and temporary emersion of the large lacustrine basins and alluvial plains created favorable conditions for early hominin occupation of the area, as attested by abundant tool industry occurrences and fossils. This study provides new constraints to better interpret the hominin migratory dynamics and the factors that influenced the location and spatial distribution during the early occupation of this region.
    Description: Published
    Description: 7056
    Description: 1A. Geomagnetismo e Paleomagnetismo
    Description: JCR Journal
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 7
    Publication Date: 2022-06-22
    Description: Thirteen samples of mortar collected from different masonry structures of the Curia of Pompey the Great and from three mixtilinear basins located within the Sacred Area of Largo Argentina were studied. Despite the use of the same volcanic deposit, known as "Pozzolane Rosse", to produce the fine aggregate in all these mortars, it was possible to highlight some distinctive features through the combination of geochemical analyses on selected trace elements and petrographic analysis under an optical microscope, allowing us to distinguish among the three groups of mortars. These types of mortars reflect a perfect coincidence between the diversity of the volcanic materials used and the different construction phases identified and documented by the analysis of the stratigraphic units: a first construction phase of Pompeian age, a second one of Augustan age and, finally, one of the medieval period. Furthermore, it was possible to ascertain two phases of construction of the basins, the second coeval with the interventions of the Augustan period. Finally, this study increases the knowledge on the methods of exploitation and selection of volcanic materials used to produce mortars in Roman times, identifying additional elements useful to establish their origin and chronology of use.
    Description: Published
    Description: 597-610
    Description: 3V. Proprietà chimico-fisiche dei magmi e dei prodotti vulcanici
    Description: JCR Journal
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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