86,842 research outputs found
Fluorophlogopite and F-rich phases in limestone clasts from the Campanian Ignimbrite quarried at Fiano (southern Italy): mineralogical, geochemical and volcanological insights.
No full textFluorine-rich metamorphosed xenoliths associated to the distal Campanian Ignimbrite (CI) tephra (Campania region,
southern Italy) have long attracted the interest of the mineralogical community (i.e. Scacchi, 1890; Zambonini, 1919;
Masi & Turi, 1972; Balassone et al., 2002). These rocks derive from the Mesozoic carbonate lithotypes of the
Campanian Apennine, embedded in the pyroclastic flow and presently resting at the bottom of the tuff formations. The
sedimentary protoliths suffered from the action of hot, volatile-rich pyroclastic flow, and consequently were affected by
thermal metamorphism to various degrees. Their peculiarity is the occurrence of F- and Mg-bearing phases, with an
ubiquitous presence of neoformed fluorite. The occurrence at Fiano quarries (the so-called “Tufare”) is the classical
locality for these rock xenoliths. Similar rocks were also found in the CI of the Caserta area, and in the Latium region
(Colli Albani). This research aims both at a crystal chemical study of fluorophlogopite occurring in the Fiano xenoliths,
and at a geochemical and volcanological survey, to constrain the petrogenesis processes related to this rare F-, Mg-rich
assemblage and to CI.
The analysed samples belong to two lithotypes: mica-bearing clasts and variably metamorphosed carbonate blocks.
The former lithotype is represented by abundant fluorite, followed by fluorophogopite, F-rich chondrodite, fluoborite,
diopside and (Fe,Mg)-oxides. Minor to trace contents of calcite, humite, tremolite, and grossular also occur. Carbonate
rocks can show calcite only, or also trace amounts of fluorite. The Fiano micas composition approaches that of the
Vesuvius micas from the 1872 eruption (Balassone et al., 2013). The micas belong to the 1M polytype and have crystal
chemical features typical of fluorophlogopites i.e., low c lattice parameter (~ 10.13 Å), (~ 2.060 Å) and (~ 3.135 Å)
distances. New data on minor to ultratrace elements amounts found in the studied clasts, together with Carbon and
Oxygen isotope data will be reported and interpreted in a petrogenetic and volcanological frame.
Balassone G., Franco E., Mattia C.A., Petti C. & Puliti R. 2002. Re-examination of fluosiderite, an unknown mineral
from southern Italy: equal to fluorine-rich chondrodite. Eur. J. Min., 14, 151-155.
Balassone G., Scordari F., Lacalamita M., Schingaro E., Mormone A., Piochi M., Petti C. & Mondillo N. 2013.
Trioctahedral micas in xenolithic ejecta from recent volcanism of the Somma-Vesuvius (Italy): crystal chemistry and
genetic inferences. Lithos, 160-161, 84-97.
Masi U. & Turi B. 1972. Frazionamento isotopico del carbonio e dell'ossigeno negli inclusi calcarei metamorfosati del
"Tufo grigio campano" Auct. di Fiano (Salerno). Per. Min., 41, 291-310.
Scacchi A. 1890. La regione vulcanica fluorifera della Campania. Mem. R. Com. Geol. It., I, 1-48.
Zambonini F. 1919. Il tufo pipernoide della Campania e i suoi minerali. Mem. Descr. Carta Geol. It., 7, 130 pp
Economics and Politics of Infrastructure Investments in Italy
No full textIl generalizzato rallentamento delle principali economie avanzate associato ai notevoli vincoli all’utilizzo di interventi di politica monetaria o fiscale ha sollecitato la (ri)valutazione dello sviluppo infrastrutturale come strumento di rilancio della crescita economica. Sia l’analisi critica della letteratura esistente che l’evidenza empirica prodotta nei saggi che compongono questa raccolta mettono in luce alcune criticità legate agli investimenti in nuove infrastrutture in Italia, suggerendo la necessità di ricondurre questi interventi in un mix bilanciato di politiche di sviluppo.The generalised economic downturn in developed countries and the significant constraints on both their monetary and fiscal policies have prompted new infrastructure investments as a tool to promote economic growth. However, both the critical analysis of the existing academic literature and the new empirical evidence offered by the papers included in this Special Issue shed new light on some potential drawbacks of infrastructure investments in Italy, suggesting that new infrastructure should be included in a balanced mix of development policies
Che fare se è assente la transilluminazione al posizionamento della PEG?
No full textPercutaneous endoscopic gastrostomy (PEG) was described for the first time in 1980 by Gauderer and Ponsky. It became the procedure of choice in most patients that are unable to eat owing due to neoplastic or neurological diseases or cerebrovascular accidents. In some cases, however, the transillumination of the gastric wall is missing and therefore another therapeutic option is required
“Critical” importance of the Silius vein system (SE Sardinia,Italy)
No full textThe late- to post-Hercynian geological evolution of Europe, as well as part of Northern Africa, is characterized by
numerous hydrothermal mineralizing events, ranging in age from the end of the orogenic compression (Permian) to the
onset of Tethys spreading (Triassic-Jurassic) (Muchez et al., 2005). The Silius vein system (SE Sardinia (Italy) is
analogous to other late- to post-Hercynian mineral systems of this type in Europe. Silius consists of two main veins,
characterized by several generations of fluorite, barite, carbonates and quartz (Boni et al., 2009). Silius is known for its
barite-fluorite, but also galena mineralizations that have been exploited until lately. Distinct fluorspar resources still exist
in the mine area. Gangue carbonates, consisting of calcite and ferroan dolomite, contain Rare Earth Elements (REE)-
bearing minerals represented by minor xenotime, and especially by synchysite-(Ce) (Mondillo et al., 2016).
To check the effective amounts of REE in the Silius orebody, representative samples of the carbonate gangue have
been collected in the underground mine. The values of LREE mainly, are in the range of 462-2071 ppm (951 ppm on
average). The average volume of the carbonate gangue still in place is considered to be around 532,000 tons, to which
may be added more 750,000 tons of carbonates discarded at the flotation plant. The corresponding total REE resource
currently occurring at Silius may be about 1,220 tons.
The discovery of REE in the Silius mine opens interesting perspectives for the exploration of subeconomic REE
concentrations in this deposits type, where REE could be recovered as by-product of the fluorite exploitation. REE
geochemistry of carbonates in other post-Hercynian fluorite veins has been widely investigated in the Harz Mts
(Germany), in the Valle de Tena (Spain) and in the El Hammam orebodies (Morocco). Even though REE occur in contents
comparable to those observed at Silius, the above deposits are not considered economic for this type of commodity till
now. Being both REE and fluorite critical raw materials for the European economy, the Silius and the other similar post-
Hercynian F-mineralizations should be now reconsidered in their double significance: not only for their fluorspar content,
but also for the possibly recoverable REEs contained in the carbonate gangue.
Boni M., Balassone G., Fedele L. & Mondillo N. 2009. Post-Variscan hydrothermal activity and ore deposits in southern Sardinia (Italy): selected
examples from Gerrei (Silius vein system) and Iglesiente district. Per. Mineral., 78, 19-35.
Mondillo N., Boni M., Balassone G., Spoleto S., Stellato F., Marino A., Santoro L. & Spratt J. 2016. Rare earth elements (REE)—Minerals in the Silius
fluorite vein system (Sardinia, Italy). Ore Geol. Rev., 74, 211-224.
Muchez P., Heijlen W., Banks D., Blundell D., Boni M. & Grandia F. 2005. Extensional tectonics and the timing and formation of basin-hosted deposits
in Europe. Ore Geol. Rev., 27, 241-267
EPMA, SIMS and FTIR investigations on sodalites and haüynes from Somma-Vesuvius volcano (southern Italy). 14th European workshop EMAS, Modern Developments and Applications in Microbeam Analysis
No full textSodalite-group minerals (sodalite, tugtupite and danalite subgroups) commonly occur in
alkaline igneous rocks, and in some hydrothermal and metamorphic rocks. These minerals
present a zeolite-like cubic structure and two structural cavities per unit cell. Cationic and
anionic contents of SSG are of interest for the study of magmatic systems; in particular, their
volatile components can be useful because they can provide key information on the genetic
environment, like degassing dynamics, fluids behaviour during hydrothermal processes and so
on [1-4]. Besides, SSG are very promising in different fields of material science, since their
(ultra)microporous structures show high flexibility and versatility in hosting tetrahedral cations
and variable channels/cavities components. Hence, they can be suitable as advanced materials
and behave as models for many technological and commercial applications [5, 6], for instance
separation processing (i.e. hydrogen from gaseous macromolecules). The present study is
focused on crystal-chemical characterization of cationic and anionic components of SSG
occurring in various igneous to metamorphic rocks and ejecta from the alkaline-potassic
Somma-Vesuvius volcano (southern Italy), as revealed by using combined microbeam
techniques, i.e., EPMA, SIMS and μ-FTIR. Previous studies on sodalite-group minerals by
means of EPMA, Raman, and LA-ICP-MS techniques focussed on halogen- (Cl, Br) and
S-contents [2, 3, 8]. To the authors’ knowledge no studies on volatiles in SSG have been
performed so far by integrated SIMS-FTIR investigations. Compared to bulk analyses, SIMS
and μ-FTIR methods are particularly pivotal to probe trace to ultra-trace contents, speciations
and orientations of an absorber across the samples [1, 7]. Our investigations show that the
studied SSG correspond to sodalite sensu stricto, nosean (sulfatic sodalite) and haüyne. SIMS
measurements on H, F and C (quantified as H2O, F and CO2, respectively) show contents:
0.02 - 5.0 wt% H2O, 0.01 - 0.14 wt% F, and 0.69 - 2.95 wt% CO2. Within the single crystals,
the F and CO2 concentrations are virtually homogeneous, whereas in terms of H2O, samples
can vary from homogenous to strongly heterogeneous. Single-crystal FTIR spectra of SSG can
be grouped into sodalites and sulphatic sodalites/haüynes, according to the occurrence of the
12CO2 absorption at 2340 cm-1 [1, 9]. The absorption due to H2O and/or OH groups occurs as a
very broad band extending from 3700 cm-1 to 3000 cm-1. In all samples FTIR data show the
presence of CO32-. μ-FTIR focal plane array imaging shows a very heterogeneous and
antithetical distribution of CO2 and especially of H2O according to the SIMS data.
[ 1] Bellatreccia F, Della Ventura G, Piccinini M, Cavallo A and Brilli M 2009 Min. Mag.
73 399-413
[ 2] Hettmann K, Wenzel T, Marks M and Markl G 2012 Am. Mineral. 97 1653-1661
[ 3] Hammerli J, Spandler C, Oliver N H S and Rusk B 2014 Metam. Geol. 32 93-112
[ 4] Wang L X, Marks M A W, Keller J and Markl G 2014 Chem. Geol. 380 133-144
[ 5] Ferraris G and Merlino S 2005 Rew. Min., Geoch. MSA 57 448 pp.
[ 6] Riley B J, Pierce D A, Frank S M, Matyáša J and Burns C A 2015 J. Nuclear Mat. 459
313–322
[ 7] Ottolini L and Le Fèvre B 2008 Microchim. Acta 161 329-336
[ 8] Hammerli J, Rusk B, Spandler C, Emsbo P and Oliver N H S 2013 Chem. Geol. 337-
338 75-87
[ 9] Balassone G, Bellatreccia F, Mormone A, Biagioni C, Pasero M, Petti C, Mondillo N and
Fameli G 2012 Mineral. Mag. 76 191-21
CRYSTAL CHEMICAL AND STRUCTURAL CHARACTERIZATION OF FLUOROAPATITES IN EJECTA FROM 1631 AND 1872 HISTORICAL LAVAS OF SOMMA-VESUVIUS VOLCANIC COMPLEX
No full text
Ni-bearing smectites in the Wingellina laterite deposit (Western Australia) at nanoscale: TEM-HRTEM evidences of the formation mechanisms
No full textNi-bearing clays represent the main ore minerals in many laterite districts. Although the world-class Wingellina deposit (Western Australia) is an oxide-dominated ore, about 30% of the total Ni resources are hosted in the saprolitic section of the tenure, making the Ni-bearing clays a strategic target to increase the future ore reserves. In this study we present a detailed micro- to nanotextural TEM-HRTEM investigation of Ni-bearing smectites, which at Wingellina represent the main mineralogical species in the phyllosilicates assemblage. Ni-bearing smectites belong mainly to the dioctahedral (i.e. montmorillonite and nontronite) and to the trioctahedral (saponite and ferrosaponite) groups. The nanoscale TEM-HRTEM imaging indicates that Ni-bearing clays occur either as a replacement of the former clay suite (i.e. polygonal serpentine and chlorite) or as porous clay aggregates (i.e. PCA). Most of PCA was found closely associated with nanometric Co-bearing Mn-oxy-hydroxides. This finding not only provides a better understanding of the early stage formation of Mn-oxy-hydroxides in laterite systems, but is also important to better constrain the Co distribution and targeting within unconventional laterite ore facies. The nanoscale HRTEM imaging coupled with SAED allowed detecting minor Ni-bearing chlorite amounts, which were not found through previous XRPD-based techniques. Moreover, the paragenetic association of chlorite with primary serpentine suggests a pre-lateritic formation for chlorite. The detection of Ni-bearing trioctahedral smectite as alteration product of primary chlorite is of relevant importance, as it fills a gap in the knowledge of ore-formation processes occurring in smectite-endowed laterites
Nuovo ritrovamento di corindone al Monte Somma
No full textAfter the occurrence described by of Balassone et al. (2001), a second finding of corundum, Al2O3, occurred
in a small fragment of carbonatic rock at San Vito quarry, Ercolano, Napoli, Campania. It is the section
of a 2 mm bluish crystal. The identification was done through SEM-EDX analysis at 30 kV excitation.Published177-1783.5. Geologia e storia dei vulcani ed evoluzione dei magmiN/A or not JCRope
- …
