Ventotene Research Articles

The Ventotene Volcanic Ridge: a newly explored complex in the central Tyrrhenian Sea (Italy)

New high-resolution geophysical data collected along the eastern margin of the Tyrrhenian back-arc basin, in the Pontine Islands area, reveal a ∼NW-SE elongated morphological high, the Ventotene Volcanic Ridge (VR), located on the northern edge of the Ventotene Basin. High-resolution multibeam bathymetry, combined with magnetic data, multi- and single-channel seismic profiles, and ROV dives, suggest that VR results from aggregation of a series of volcanic edifices. The summit of these volcanoes is flat and occurs at about 170 m water depth. Given their depths, we propose that flat morphologies were probably caused by surf erosion during Quaternary glacial sea level lowstands. Seismic stratigraphy together with magnetic data suggest that the volcanic activity in this area is older than 190–130 ka age and may be coeval with that of Ventotene Island (Middle Pleistocene). The submarine volcanoes, located 25 km north of Ventotene, are part of a ∼E-W regional volcanic alignment and extend the Pontine volcanism landward toward the Gaeta bay. Integration of structural data from multichannel seismic profiles in this sector of the eastern Tyrrhenian margin indicates that several normal and/or transtensional faults, striking WNW-ESE, NNW-SSE, and NE-SW, offset the basement and form alternating structural highs and depressions filled by thick, mostly undeformed, sedimentary units. Arc-related magmatism is widespread in the study area, where the VR is placed at the hangingwall of the west-directed Apennines subduction zone, which is undergoing tensional and transtensional tectonics. Bathymetric and topographic evidence shows that VR lies in between a major NE-SW trending escarpment east of Ponza and a NE-SW trending graben southwest of the Roccamonfina volcano, a NE-SW transfer zone that accommodate the extension along this segmented portion of the margin. This suggests that the interaction between NE-SW and NW-SE trending fault systems acts as a structural control on location of eruptive centers, given that main volcanic edifices develop along the NW-SE direction, compatible with the extensional setting of the Tyrrhenian basin.

New insights on the petrology of submarine volcanics from the Western Pontine Archipelago (Tyrrhenian Sea, Italy)

The Pontine Islands form a volcanic archipelago in the Tyrrhenian Sea. It consists of two edifices, the islands of Ponza, Palmarola and Zannone and the islands of Ventotene and Santo Stefano, respectively. The Archipelago developed during two main volcanic cycles in the Plio-Pleistocene: 1) the Pliocene episode erupted subalkaline, silica-rich volcanic units, which constitute the dominant products in the western edifice (Ponza and Zannone Islands); 2) the Pleistocene episode erupted more alkaline products, represented by evolved rocks (trachytes to peralkaline rhyolites) in the islands of Ponza and Palmarola and by basic to intermediate rocks in the eastern edifice (Ventotene and Santo Stefano Islands). In this paper we present new geochemical and petrological data from submarine rock samples collected in two oceanographic cruises and a scuba diving survey. The main result is the recovery of relatively undifferentiated lithotypes that provide further insights on the magmatic spectrum existing in the Pontine Archipelago, allowing modelling of the whole suite of rocks by fractional crystallization processes. New major and trace element data and thermodynamic constrains (by the software PELE) indicate the existence of three distinct evolutionary trends corresponding to a HK calcalkaline series in the Pliocene, followed by a transitional and then by a shoshonite series in the Pleistocene. In particular, the transitional series, so far overlooked in the literature, is required in order to explain the genesis of several peralkaline felsic rocks recognized in the Archipelago. On the whole, the new geochemical data i) confirm the orogenic signature of the suites, ii) allow to rule out an anatectic origin for both subalkaline and peralkaline rhyolites and iii) indicate highly heterogeneous mantle sources, due to crustal components variously recycled in the mantle via subduction.

Joining up land and marine seismic data: Case study from Procida and Ventotene Islands (Tyrrhenian Sea, Italy)

The seismic refraction survey, routinely used to obtain information on subsurface geology, has a limited use in the foreshore zone. We have evaluated a nonstandard approach to acquire seismic data in the backshore-foreshore area, joining up land and marine seismic data. The innovative part was the acquisition of a continuous seismic profile that allowed the recording of high-resolution data in a transition zone (TZ) to establish an integrated approach for improving the land-marine seismic model in areas characterized by a complex near surface geology. To achieve this objective, two seismic tests were carried out along the beaches of the Tyrrhenian islands of Procida and Ventotene. We defined the P-wave [Formula: see text] and S-wave velocities [Formula: see text] with depth by integrating the tomography of the refracted first arrivals ([Formula: see text] velocities versus depth) with the inversion of the phase velocities dispersion curves extracted from the surface waves (1D [Formula: see text] velocities models). Working with both seismic methods allowed us to overcame the limitations of each approach and to compare and check the obtained results. The velocity models enabled resolution of the near-surface velocity variations and definition of refractors down to a maximum depth of 40 m below ground level. This has provided useful insights to map the 2D bedrock surface and to evaluate ground stiffness and dynamic behavior of soil. Our study, aiming to demonstrate the feasibility of high-resolution seismic surveys in the land-sea TZ, proved that the use of a marine streamer connected to land cable, was a powerful tool to define different subsoil structures to assist with future planning (coastal management) of these areas.

Sociality of sperm whale off Ischia Island (Tyrrhenian Sea, Italy)

ABSTRACT The sperm whale (Physeter macrocephalus) is one of the eight species of cetaceans routinely encountered in the Mediterranean Sea; however, information on the social organization of sperm whales living in the basin remains scarce. The social behaviour of sperm whales within female units, and groups of males are reported, made over an 11‐year period (2002–2012) in waters around the islands of Ischia and Ventotene (Tyrrhenian Sea, Italy), an area characterized by the presence of a submarine canyon system and a coastal marine protected area (‘Regno di Nettuno’ MPA). Different types of aggregations were identified, consisting of social units and two arrangements of males (bachelor groups and clusters). Close clustering at the surface was recorded both for social units and bachelor groups, with evidence for long‐term relationships between females (as expected from other studies) and, surprisingly, also among some immature males. Such long‐term associations between individuals in bachelor groups may allow immature males to benefit in several ways, including optimizing feeding efficiency. Copyright © 2014 John Wiley & Sons, Ltd.

Adding ICT to Transportation Systems: Monitoring and Management System for the Electric Vehicle Fleet on the Island of Ventotene

 Abstract—This paper describes an Automatic Vehicle Monitoring and Location System developed to be tested on the municipal fleet of electric and hybrid vehicles circulating on the small island of Ventotene in Italy. The system allows to determine the geographic position and to provide data about the vehicles, and sends the information to a remote server. Transportation systems in Europe are in the early stage of being radically transformed by Information and Communications Technology (ICT). Adding ICT to the transport infrastructure, vehicles and transport management is slowly leading to the development of Intelligent Transport Systems (ITS), which include a wide and growing suite of technologies and applications (1). These systems deal with several combinations of communication, computer and control technologies developed and applied in the domain of transport to improve system performance, transport safety, efficiency, productivity, level of service, environmental impact, energy consumption and mobility. Other benefits come from expanding economic and employment growth. The potential of ITS has encouraged the EU to make them an integral part of the Common Transport Policy (2), with the aim of establishing a coordinated infrastructure for ITS in Europe and to contribute to the development, assessment and demonstration of ITS applications, laying the groundwork for a large deployment of ITS in the future. To classify ITS applications five primary categories can be

Differential migration and body condition in Northern Wheatears (Oenanthe oenanthe) at a Mediterranean spring stopover site

In many species of migratory birds, individuals of different populations, sexes and age classes migrate at different times and manage their energy reserves according to their specific migratory strategies. In this study, we analyzed the migratory patterns related to geographic provenance, sex and age in the Northern Wheatear Oenanthe oenanthe, a long-distance migratory passerine, during one spring season on the island of Ventotene (Italy), a Mediterranean stopover site. Individuals of different sex and age did not differ significantly in their average date of passage, but birds with longer and more pointed wings passed through later in the season than birds with shorter wings. Morphometric measurements combined with isotopic analysis revealed that late-arriving birds probably belonged to more distant breeding populations and this later date of passage probably mirrors the delayed arrival observed at their northern breeding grounds. Adult birds arrived in better condition than second-year birds, possibly as a result of better energy management. Birds passing through later in the season were also in better condition, which might be explained by their wing morphology favoring endurance flights and thus improving energetic efficiency when crossing the Mediterranean. Birds which migrate longer distances might also carry larger fuel loads to safely complete their journey. This intra-specific study shows that the birds’ organization of their migration schedule is population-specific in correspondence to the temporal requirements which depend on the different environmental conditions on the breeding grounds.

Flexible tuning of departure decisions in response to weather in black redstarts Phoenicurus ochruros migrating across the Mediterranean Sea

Departure and stopover decisions are crucial for a successful migration. Such decisions are modulated by a complex interplay between endogenous (physiological state) and external factors, such as weather (e.g. wind) and geography (ecological barriers). In this study of the black redstart Phoenicurus ochruros, a short-distance migrant passerine, we investigate the effect of weather, as gauged by tailwind and crosswind conditions, rainfall, temperature, and barometric pressure, on departures from a stopover site in the central Mediterranean Sea, off the western coast of Italy (Ventotene island), during both spring and autumn migration. We found that stopover duration was longer in birds arriving with lower fat stores, and that birds departed with generally favourable weather conditions (favourable tailwinds, weak or no crosswinds, low rainfall, high temperatures, and high pressure). However, the effects of weather on departure decisions were stronger in autumn: this could be related to 1) a seasonal difference in selection pressures for early arrival at the goal areas, that are expected to be stronger in spring than in autumn or 2) a difference in the residual extent of sea crossing since, in autumn, birds are confronted with a much longer non-stop sea crossing (at least 300 km) than in spring (� 50 km). In spring we also found males to leave the study site under less favourable tailwinds than females, and adults to leave with more favourable tailwinds than young. Our findings indicate that departure decisions are flexible and differently affected by weather in different seasons, either because of seasonal effects or because of different distances to be covered before reaching the next stopover site. Moreover, our study suggests that sex-specific weather selectivity should be regarded among the proximate factors affecting differential spring migration of either sex.

Pollen Couriers Across the Mediterranean: The Case of Migrating Warblers

Cecere J.G., Cornara L., Mezzetta S., Ferri A., Spina F. & Boitani L. 2011. Pollen couriers across the Mediterranean: the case of migrating warblers. Ardea 99: 33–42.At stopovers sites in the Sahara and on Mediterranean islands, European warblers may feed on nectar. As a consequence of this behaviour the pollen of exploited plants often sticks on the birds' bill or plumage. We analyzed pollen samples carried by migrating warblers staging at Ventotene Island (Italy), a stopover site located in the Central Mediterranean and reached by large numbers of birds after a direct flight from North Africa. We discuss the possible role of migrants as pollen vectors. A total of 38 plant taxa were recorded in the pollen samples collected on 147 migrants. Pollen of Brassica sp., Ferula communis, Citrus sp. and Eucalyptus sp. were most commonly found. The nectar of the first two plants is largely exploited by warblers on Ventotene and the presence of their pollen on plumage is principally due to nectar feeding in situ. On the contrary, Citrus sp. and Eucalyptus sp., which are scarce and absent on the island respectively, were mainly collected on dried and agglutinated samples and their presence is likely to be due to nectar feeding at other sites than Ventotene. The other 34 plant taxa were recorded with low frequencies. Overall, the data suggest that nectar feeding migrants could play a role as pollen vectors only for Citrus sp., Eucalyptus sp., F. communis and Brassica sp. However, the other less common plant taxa could also be useful markers of migration routes. We found species-specific relationships between bird species and the plants used for nectar feeding: short-distance migrants (mainly Eurasian Blackcap Sylvia atricapilla and Subalpine Warbler S. cantillans) land on Ventotene when Brassica sp. flowers are more abundant and they mainly carry the pollen of this species. On the contrary, long-distance migrants (Garden Warbler S. borin and Common Whitethroat S. communis) principally transport the pollen of F. communis, whose flowering period takes place at the same time as their staging period on the island. The study underlines the tendency of warblers towards nectar feeding during migration.

Short communication: Absence of protandry in a population of Gray Catbirds Dumetella carolinensis

Sex-based differential arrival on the breeding grounds at the completion of migration has been poorly studied in monochromatic and monomorphic species because individuals are difficult to sex without recapture or molecular tests. We examined sex-based arrival timing to the breeding grounds of the Gray Catbird Dumetella carolinensis, a monochromatic species. We also examined differences in size and arrival by age as these are well documented to affect arrival timing. Older birds were larger than younger birds, and older males were larger than older females. Older birds arrived back on the breeding grounds earlier than younger birds, as documented in many species, but males did not precede females. Our results provide evidence of sexual size dimorphism in Catbirds and add to a growing body of information on arrival timing in monochromatic species. Differences in intensity of sex-based competition for breeding resources are hypothesized as the primary selective force for one sex to precede the other to the breeding grounds (Kokko 1999, Kokko et al. 2006). Typically, males arrive at the breeding grounds in advance of females (Morbey & Ydenberg 2001), a phenomenon known as protandry (Rubolini et al. 2004). This is because males are thought to experience more intensive selective pressure for acquiring territories or other resources for attracting a mate than females (but see Kokko et al. 2006 for a discussion of why females may also be under selection pressure for earlier arrival to compete for resources or mates). Furthermore, comparative studies suggest that the extent of sexual selection experienced by males, as evidenced by the degree of sexual dichromatism (Moller & Birkhead 1994, Owens & Hartley 1998), sexual size dimorphism (Owens & Hartley 1998, Dunn et al. 2001), polygyny or rate of extra-pair paternity (Coppack et al. 2006), affects the degree of protandry. While protandry is well documented in dimorphic species (Rubolini et al. 2004), little is known about arrival dates by sex in monomorphic or monochromatic species (Rubolini et al. 2004, Edwards & Forbes 2007, Newton 2008). The primary reason for this is the difficulty in sexing individuals upon arrival at the migratory destination. Moreover, the limited studies to date have produced equivocal results. For example, male Spotted Flycatchers Muscicapa striata preceded females during passage on the island of Ventotene, Italy, (Mabey 2002), and male White-throated Sparrows Zonotrichia albicollis and Least Flycatchers Empidonax minimus preceded females during spring migration at Long Point Observatory, Ontario, Canada (Mills 2005). In contrast, Edwards and Forbes (2007) presented evidence that Song Sparrows Melospiza melodia did not exhibit protandry upon arrival at breeding grounds in Ontario. Our research on arrival and breeding in the Gray Catbird afforded us the opportunity to assess arrival timing by sex and age in a songbird migrant described as monochromatic and monomorphic (Cimprich & Moore 1995). One advantage of our study is that we captured birds both during the arrival period and throughout the breeding season, permitting us to determine an individual’s sex and relate it back to when it arrived at breeding grounds in northeastern Pennsylvania. Although there are several hypotheses regarding differences (or lack of differences) in arrival timing between the sexes (Morbey & Ydenberg 2001) here we focus on assessing whether catbirds are indeed monomorphic and whether they exhibit protandry.

Safety of recreational scuba diving in type 1 diabetic patients: The Deep Monitoring programme

Aim To verify whether, with thorough practical and theoretical training, well-controlled, non-complicated diabetic patients can safely go diving underwater with no additional medical or metabolic risks. Methods Twelve diabetic patients participated in the study after undergoing training focused on their diabetic status. Two dives per day were scheduled during two five-day stays on the island of Ventotene (Italy). Capillary blood glucose (BG) was checked at 60, 30 and 10 minutes before diving, and corrective measures adopted if necessary, based on BG absolute levels and dynamics. A device for continuous subcutaneous glucose monitoring (CGM), expressly modified for the purpose, was worn during dives. Results Data were gathered from 90 dives; mean BG at 60, 30 and 10 minutes before diving was 205.8 ± 69.6 mg/dL, 200.0 ± 66.4 mg/dL and 200.5 ± 61.0 mg/dL, respectively. In 56 of the 90 dives, supplementary carbohydrates or insulin were necessary, but only one dive was interrupted on account of hypoglycaemic symptoms. Mean post-dive BG was 158.9 ± 80.8 mg/dL. CGM recordings showed that glucose levels gradually decreased during the dives (nadir: –19.9%). Conclusion Experienced, well-controlled, complication-free young diabetic patients can safely go scuba diving, provided that they apply a rigorous protocol based on serial pre-dive BG measurements. The specific variables of underwater diving do not appear to involve significant additional risks of hypoglycaemia.

Assessment of H 2- and H 2O-based renewable energy-buffering systems in minor islands

The paper assesses the energy and environmental performance of two solutions designed to complement renewable energy (RE) technologies, in stand-alone power system (SAPS) configuration typical of minor Mediterranean islands, by converting the available RE surplus. The studied SAPS, based on the Ventotene island demographic, meteorological and load data, features high renewable energy penetration onto the load power demand, i.e. up to 55.25% share of peak power capacity. Transient models have been developed to simulate the storage process of winter renewable energy surplus and the time-dependent matching among SAPS electric demand and the stochastic renewable power contributions combined with energy surplus conversion systems. The study compares a hydrogen-based system and a desalinated water-production system, proposed as two effective alternatives for renewable energy seasonal buffering in an island context. The comparative analysis of the time-dependent system's behaviour has been investigated with an hourly distribution over the period of one reference year, in terms of fuel consumption and hydrogen system energy storage or desalination capacity. The assessment is carried out by taking performance indicators, SAPS fuel savings, as well as stored and dump power data. The study demonstrates the suitability of both the models for the winter renewable energy buffer, in order to improve to the matching of peak energy and water demands.

Assessment of Renewable Energy Solutions in an Italian Small Island Energy System Using a Transient Simulation Model

This paper presents a transient model of the energy system of the small Italian island of Ventotene. The model has been developed as a tool to validate the performance related to the integration of renewable energy technologies and energy efficiency measures into the island stand-alone power system, in presence of seasonal-dependent electric load equilibrium conditions. A hydrogen-based energy system has been proposed as an effective option for the seasonal buffering of the stochastic power contribution from renewable energy sources. The time-dependent behavior of the hybrid, diesel, and hydrogen-renewable, power generation system has been investigated by matching it with the electric load data with an hourly distribution over the period of one reference year. The technical feasibility and the behavior of the systems have been evaluated in terms of its electric and environmental performance.

Melt inclusion geochemistry and computer modeling of trachyte petrogenesis at Ponza, Italy

The Punta della Guardia trachytic unit on the island of Ponza, Italy is thought to represent the latest stage in the evolution of a parent basaltic melt in a shallow magma chamber undergoing fractional crystallization. To test this hypothesis, melt inclusions (MI) have been analyzed to constrain the crystallization history of the Ponza trachyte. The trachyte is a weakly porphyritic lava that contains phenocrysts of plagioclase, K-feldspar, clinopyroxene and biotite. Melt inclusions were observed and measured in plagioclase, clinopyroxene and K-feldspar. The crystallized devitrified melt inclusions were heated to dissolve (melt) the crystals, quenched to a homogeneous glass, and then analyzed for major elements by electron microprobe. Two different heating protocols, one involving rapid heating in a one-atmosphere furnace, and the other involving slower heating in a microscope heating stage, were used to homogenize the inclusions in order to investigate possible effects of heating rates on inclusion composition. No detectable difference was found. Melt inclusion compositions suggest that the magma evolved from an early phase dominated by clinopyroxene±plagioclase crystallization to a late stage in which melt composition was controlled by precipitation of two feldspars. The potential basaltic parent magma does not crop out on Ponza, although more primitive and coeval basalts and trachybasalts are found on nearby Ventotene Island, which is considered to be co-magmatic with Ponza. Using the program MELTS, we have compared results obtained from melt inclusions in the Ponza trachyte with melt compositions predicted for fractional crystallization of a magma having the composition of the Ventotene trachybasalt. Crystallization trends predicted by MELTS are consistent with data from melt and host phases, although differences in measured and predicted compositions are significant in some cases. In spite of these differences, the model results and measured compositions are consistent with the hypothesis of a genetic link between the magmatism of Ponza and Ventotene.

Nectar consumption of warblers after long‐distance flights during spring migration

The consumption of nectar by European passerines has been reported only occasionally. In this study we investigated the occurrence and significance of nectar consumption of small passerine birds on spring migration after crossing the Mediterranean Sea. On Ventotene Island in the Tyrrhenian Sea, four migrating species of Sylvia warblers [Garden Warbler S. borin, Subalpine Warbler S. cantillans, Whitethroat S. communis, Blackcap S. atricapilld) regularly foraged on the two most common flowering species at that time of year, Brassica fruticulosa (Cruciferae) and giant fennel Ferula communis (Umbelliferae), while other species visited flowers only occasionally or not at all. Feeding behaviour, pollen traces on the head, and the examination of pollen and sugar remains in droppings indicated that nectar was the main target of the Sylvia warblers, rather than pollen or insects on the flowers. This was confirmed by food choice experiments indicating a clear preference by Garden Warblers and Whitethroats for nectar from artificial flowers over mealworms. Although conclusive experiments are not available, we hypothesize that nectar might be a diet easy to obtain and to absorb for birds after a long‐distance flight in which they have incurred a depletion of energy stores and a reduction of the digestive tract.

Mantle source heterogeneity in the Campanian Region (South Italy) as inferred from geochemical and isotopic features of mafic volcanic rocks with shoshonitic affinity

Major, trace element and Sr-Nd-isotopic data on mafic volcanic rocks with shoshonitic affinity from the islands of Procida and Ventotene (Campanian Region, South Italy) are reported. Within-suite chemical and isotopic variations are interpreted in terms of open system differentiation processes held responsible for enrichment in a number of trace elements and for radiogenic Sr observed in both Procida and Ventotene volcanic sequences. Conversely, trace element contents and Sr-Nd-isotopic compositions of the least-evolved among the investigated samples are thought to reflect source region characteristics with only negligible crustal contamination of the primary magmas.

Proximal depositional facies from a caldera-forming eruption: the Parata Grande Tuff at Ventotene Island (Italy)

Ventotene and S. Stefano islands form part of the southeastern flank of a Pleistocene stratovolcano. The products of 27 eruptions, the majority of which have never been previously identified, comprise the two islands. These products consist chiefly of pyroclastic deposits with only three effusive episodes represented. The youngest and most prominent deposit, hereafter called Parata Grande Tuff, was produced by an eruption that represents the culmination of more than 0.5 Ma of volcanic evolution and that formed a 3-km-wide summit caldera. The Parata Grande Tuff is the focus of this study and consists mostly of pyroclastic flow deposits overlying basal pumice and ash fall beds. The studied sections crop out as far as 2 km from the caldera rim. The flow deposits sequence can be represented by four different lithofacies: (1) massive facies, originated by rapid sedimentation of grains through a boundary layer; (2) coarse-tail graded facies, formed with a relatively lower fallout rate of particles from the suspension toward the boundary layer; (3) inverse-graded facies, considered to have formed by gradual deposition from the base to the top of a traction carpet, when the shear stress dropped below the threshold value to support the weight of the clasts; and (4) sand-wave facies, the product of deposition from an unsteady low-concentration flow. The base of the pyroclastic flow succession is welded and thickens in topographic depressions. The welding of deposits with traction structures and undeformed coarse pumice clasts probably occurred during the final stages of deposition of a formerly paniculate pyroclastic flow. The flow deposits that overlie the welded succession show a drastic increase and change of lithic types that are interpreted to reflect the collapse of the roof of the reservoir triggering magma/water interaction. The uppermost part of the sequence is a succession of layers with dunes and cross stratification alternating with massive beds. The stratified and heterogeneous succession of flow deposits could be due to the unsteady nature of the flow during the final phase of the eruption. A vertical trend of sedimentary facies from massive, to coarse-tail-graded into sand-wave lithofacies is dominant in the PGT sequence and is interpreted as a depositional cycle. Each cycle is suggestive of deposition from a flow that was progressively diluted with time.

Fluid inclusion evidence for magmatic silicate/saline/CO2 immiscibility and geochemistry of alkaline xenoliths from Ventotene Island, Italy

Fluid and melt inclusions and geochemical features of alkali syenite, mafic, and ultramafic cumulate xenoliths in the last ignimbritic event (volcanism up to 300 ky.b.P.) at the island of Ventotene in the Pontine archipelago (Gaeta Gulf) were investigated to establish the genesis and evolution of the fluids trapped in the inclusions. Ranges in lead isotopic compositions of the xenoliths as a group are narrow: 206Pb/204Pb:18.778–18.864; 207Pb/204Pb:15.641–15.701; 208Pb/204Pb:38.858–39.090; the values overlap among the groups, implying that the xenoliths are closely related. The xenoliths straddle the best-fit line describing the regional NW-SE variation of values for uranogenic Pb in volcanic rocks from the Roman alkaline province. The similarity between the xenoliths and volcanic rocks permits the interpretation that the xenoliths are representative of the source region of the volcanic rocks, residues after partial melting of the source region or fractional crystallization of the volcanic rocks, or even that the xenoliths represent assimilants obtained during the evolution of the magmas that produced the volcanic rocks.Xenoliths belonging to the ultramafic-mafic cumulate group contain only silicate melt inclusions ± vapor bubble ± droplets of an opaque phase and rarely some CO2 trapped in silicate melt inclusions. Xenoliths in the alkali syenite group have three types of fluid inclusions: (1) single phase vapor and silicate melt inclusions; (2) two-phase silicate melt + salt, silicate melt + CO2 (V), aqueous (L + V), and silicate melt + vapor inclusions, and (3) three-phase and multiphase inclusions: CO2 (L) + CO2 (V) + H2O; silicate melt + saline melt + H2O ± birefringent or opaque trapped minerals; H2O + salt + silicate glass ± birefringent trapped minerals.During heating experiments, melting of salt occurs at temperatures from 565 to 815°C, depending on the water content of the inclusions. Homogenization of the vapor bubble occurs from 850–1160°C, and complete melting of the silicate glass at about 950°C. The highly variable proportions of the individual phases in the silicate melt + salt + H2O inclusions and the coexistence of silicate melt + CO2 inclusions indicates immiscibility during the crystallization of the magma.Primary and secondary CO2 inclusions in the alkali syenite suite indicate lower densities (from 0.10 to 0.22 g/cm3) than those resulting from primary CO2 inclusions in the gabbroic suite (from 0.34 to 0.42 g/cm3).The P-T trajectory of the probable fluid evolution path shows that the crystallization of gabbro occurred between ∼1 and 1.4 kbars, whereas alkali syenite crystallized between ∼200 and 400 bars. The secondary H2O inclusions in alkali syenite were trapped in the later stages of the hydrothermal process and at much lower temperatures (130–290°C), but at pressures relatively close to those of alkali syenite crystallization. The almost isobaric conditions during the final stage of the fluid evolution path are explained by the very shallow emplacement of the alkali syenite intrusive body.

Lothian, Curtis, Kimber and the Federal Union Movement (1938-40

The idea of a European federation enjoyed a brief period of success in Britain in the year leading up to and the early part of the second world war. During this period, a large and powerful literature was produced by a number of distinguished representatives of liberal and socialist thought, such as Lionel Robbins, Barbara Wootton, Lord Beveridge, Lionel Curtis, William Curry, Ivor Jennings, Ronald Gordon Mackay, James Meade, Kenneth Wheare and Lord Lothian. This literature, which had a direct or indirect influence on British political thinking at the time, has been almost completely forgotten in Britain today. But it is held in high regard by continental scholars, especially in Italy, where it is referred to as the 'Anglo-Saxon Federalist School' and thought of as the most illuminating contribution to the evolution of European federalist thought.' The renaissance of the federal idea on the continent from 1943 owed much to the writings of Lothian, who, in Great Britain, is generally remembered for his role in the evolution of the British Empire into the Commonwealth and in the forging of closer links with the United States. On the continent, however, his importance lies in his writings for the federalist movement a facet of his career neglected in Great Britain. The most influential and dynamic starting-point of federalist resistance was probably the island of Ventotene, off the coast of Naples, where Altiero Spinelli and Ernesto Rossi were confined as anti-fascist militants. At the beginning of 1939, Luigi Einaudi (later to become President of the Italian Republic), who was then Professor of Economics at the University of Turin and one of the very few liberal intellectuals to whom the fascists accorded a certain freedom of speech, sent Rossi some books by British federalists which he had received from the Federal Union. Among them was Pacifism is not Enough. Spinelli explained why these writings had influenced him: