Vincenzo Morra

The role of lower continental crust and lithospheric mantle in the genesis of Plio-Pleistocene volcanic rocks from Sardinia (Italy)

Abstract The first comprehensive chemical and Sr–Nd–Pb isotopic data set of Plio–Pleistocene tholeiitic and alkaline volcanic rocks cropping out in Sardinia (Italy) is presented here. These rocks are alkali basalts, hawaiites, basanites, tholeiitic basalts and basaltic andesites, and were divided into two groups with distinct isotopic compositions. The vast majority of lavas have relatively high 87Sr/86Sr (0.7043–0.7051), low 143Nd/144Nd (0.5124–0.5126), and are characterised by the least radiogenic Pb isotopic composition so far recorded in Italian (and European) Neogene-to-Recent mafic volcanic rocks (206Pb/204Pb=17.55–18.01) (unradiogenic Pb volcanic rocks, UPV); these rocks crop out in central and northern Sardinia. Lavas of more limited areal extent have chemical and Sr–Nd–Pb isotopic ratios indicative of a markedly different source (87Sr/86Sr=0.7031–0.7040; 143Nd/144Nd=0.5127–0.5129; 206Pb/204Pb=18.8–19.4) (radiogenic Pb volcanic rocks, RPV), and crop out only in the southern part of the island. The isotopic ratios of these latter rocks match the values found in the roughly coeval anorogenic (i.e. not related to recent subduction events in space and time) mafic volcanic rocks of Italy (i.e. Mt. Etna, Hyblean Mts., Pantelleria, Linosa), and Cenozoic European volcanic rocks. The mafic rocks of the two Sardinian rock groups also show distinct trace element contents and ratios (e.g. Ba/Nb>14, Ce/Pb=8–25 and Nb/U=29–38 for the UPV; Ba/Nb

The Mt. Vulture volcanic complex (Italy): evidence for distinct parental magmas and for residual melts with melilite

SummaryNew data of mineral compositions, whole-rock major and trace element contents are presented for lava flows and dykes of Mt. Vulture volcano (southeastern Roman Magmatic Province). The dominant rock series ranges from basanite, through tephrite and foidite, to phonolite. Diopsidic to Fe-salitic (hedenbergitic) clinopyroxene is the major phenocryst phase, and shows a very strong Ti- and Al-enrichment trend (up to 5 wt% TiO2 and 12 wt% Al2O3). Phonolites have Fe-rich pyroxenes low in Ti and Al, as a consequence of fractionation of Ti-magnetite and/or melanite garnet.Feldspar ranges in composition from bytownite to Ba- and Sr-rich anorthoclase (up to 7 wt % BaO and 4 wt % SrO); the latter is present in the groundmass of mafic and intermediate rocks. Phonolites are characterized by anorthoclase and sanidine with Ba-rich cores, and with Ba-depleted rims.Subordinate melilite-bearing rocks are also present, and are characterized by melilite with a very large compositional variation, Ca-rich nepheline (up to 8 wt% CaO) and lack of feldspar and amphibole. Some of them also show calcite-rich ocellar structures, possibly due to liquid immiscibility. They have also major and trace element contents different from those of the feldspar-bearing rocks. This all indicates distinct parental magmas for feldspar-bearing and melilite-bearing rocks. These latter were likely generated by differentiation processes starting from olivine- and melilite-bearing ultramafic parental magmas.Mineral compositions and suitable phase diagrams indicate that the Melfi haüynophyre, which is the most MgO-poor melilite-bearing rock of Mt. Vulture, is close to a residual melt analogous to phonolite, but in petrogenetic systems with melilite and without feldspar.The high- to very high-titanium content of most of the ferromagnesian phases, despite a relatively low TiO2 of primitive Mt. Vulture rocks, is absent in other rocks of similar degree of evolution in the Roman Province. It resembles that found in anorogenic magmas and gives further indications for a within-plate signature in this particular volcanic complex.ZusammenfassungEs werden neue Daten über Mineralzusammensetzungen sowie Haupt- und Spurenelemente des Gesamtgesteins für Lavaflüsse und Gänge des Mt. Vulture Vulkans (südöstliche Römische Magmatische Provinz) vorgestellt. Die auftretenden Gesteinsabfolgen reichen von Basaniten über Tephrite und Foidite zu Phonolithen. Diopsidischer bis Fe-salitischer (hedenbergitischer) Klinopyroxen stellt die hauptsächlichen Einsprenglinge und zeigt starke Ti- und Al-Anreicherungen (bis zu 5 Gew% TiO2 und 12 Gew% Al2O3). Phonolite weisen als Konsequenz der Fraktionierung von Ti-Magnetit und/oder Melanit-Granat Fe-reiche Pyroxene mit niedrigen Ti- und Al-Gehalten auf.Der Feldspat reicht in seiner Zusammensetzung von Bytownit zu Ba- und Si-reichem Anorthoklas (bis zu 7 Gew%/o BaO und 4 Gew% SrO), der letztgenannte findet sich in der Grundmasse mafischer und intermediärer Gesteine. Phonolithe werden durch das Auftreten von Anorthoklas und Sanidin mit Ba-angereicherten Kernen und Ba-abgereicherten Rändern charakterisiert.Untergeordnet treten auch Melilith-führende Gesteine auf. Sie sind durch Melilithe mit einer großen kompositionellen Variation, durch Ca-reichen Nephelin (bis 8Gew% CaO) und durch das Fehlen von Feldspat und Amphibol gekennzeichnet. Einige dieser Melilithe zeigen auch Calcitreiche ocellare Strukturen, die möglicherweise aufgrund der Nicht-Mischbarkeit der Schmelzen entstanden sind. Sie weisen auch Gehalte an Haupt- und Spurenelementen auf, die von jenen Feldspat-führender Gesteine abweichen. All dies zeigt verschiedene Ausgangs-Magmen für Feldspat-führende und Melilith-führende vulkanische Gesteinean. Die Melilithgesteine entstanden wahrscheinlich durch Differentiationsprozesse aus Olvin- und Melilith-führenden ultramafischen Magmen.Mineralzusammensetzung und die entsprechenden Phasendiagramme zeigen, daß der Melfi Haüynophyr, welcher das MgOärmste Melilith-führende Gestein des Mt. Vulture ist, nahe an einer Ausgangschmelze analog zu einem Phonolith liegt, allerdings in einem petrogenetischen System mit Melilith und ohne Feldspat.Der hohe bis sehr hohe Titan-Gehalt der meisten ferromagnesischen Phasen fehlt, trotz des niedrigen TiO2-Gehaltes primitiver Mte. Vulture Gesteine, in anderen Gesteinen ähnlicher Entwicklung in der Römischer Magmatischen Provinz. Dies ähnelt anorogenen alkalischen Magmen und ist ein weiterer Hinweis auf eine Intra-Platten Signatur für diesen besonderen vulkanischen Komplex.

High-Mg subduction-related Tertiary basalts in Sardinia, Italy

Abstract The Oligo-Miocene volcanics (32-15 Ma), which occur in the Oligo-Miocene Sardinian Rift, were interpreted in the literature as an intracontinental volcanic arc built upon continental crust about 30 km thick. They are characterized by a close field association of dominantly andesites and acid ignimbrites, with subordinate basalts. In this paper we deal with the origin and evolution of recently discovered high-magnesia basalts aged ca. 18 Ma occurring in the Montresta area, northern Sardinia, relevant to the petrogenesis of the Cenozoic volcanics of Sardinia. The igneous rocks of the Montresta area form a tholeiitic, subduction-related suite. Major-element variation from the high-magnesia basalts (HMB) to high-alumina basalts (HAB) are consistent with crystal/liquid fractionation dominated by olivine and clinopyroxene. Proportions of plagioclase and titanomagnetite increase from HAB to andesites. Initial 87 Sr 86 Sr ratios increase with differentiation from 0.70398 for the HMB to 0.70592 for the andesites. This suggests concomitant crustal contamination. The geochemical characteristics of the high-magnesia basalts are typical of subduction-related magmas, with negative Nb, Zr and Ti spikes in mantle-normalized diagrams. It is proposed that these high-magnesia basalts were produced by partial melting of a mantle source characterized by large-ion lithophile elements (LILE) enrichment related principally to dehydration of subducted oceanic crust. Chondrite-normalized rare earth elements (REE) patterns indicate that the lavas are somewhat enriched in light rare earth elements (LREE), with flat heavy rare earth elements (HREE) patterns. This evidence is consistent with a spinel-bearing mantle source. The sub-parallel chondrite-normalized patterns show enrichment with differentiation, with a greater increase of LREE than HREE. The occurrence of high-magnesia basalts at 18 Ma in Sardinia appears to be correlated with and favoured by pronounced extensional tectonics at that time.

Atorvastatin combined to interferon to verify the efficacy (ACTIVE) in relapsing-remitting active multiple sclerosis patients: A longitudinal controlled trial of combination therapy

A large body of evidence suggests that, besides their cholesterol-lowering effect, statins exert anti-inflammatory action. Consequently, statins may have therapeutic potential in immune-mediated disorders such as multiple sclerosis. Our objectives were to determine safety, tolerability and efficacy of low-dose atorvastatin plus high-dose interferon beta-1a in multiple sclerosis patients responding poorly to interferon beta-1a alone. Relapsing—remitting multiple sclerosis patients, aged 18—50 years, with contrast-enhanced lesions or relapses while on therapy with interferon beta-1a 44 µg (three times weekly) for 12 months, were randomized to combination therapy (interferon + atorvastatin 20 mg per day; group A) or interferon alone (group B) for 24 months. Patients underwent blood analysis and clinical assessment with the Expanded Disability Status Scale every 3 months, and brain gadolinium-enhanced magnetic resonance imaging at screening, and 12 and 24 months thereafter. Primary outcome measure was contrast-enhanced lesion number. Secondary outcome measures were number of relapses, EDSS variation and safety laboratory data. Forty-five patients were randomized to group A (n = 21) or B (n = 24). At 24 months, group A had significantly fewer contrast-enhanced lesions versus baseline (p = 0.007) and significantly fewer relapses versus the two pre-randomization years (p < 0.001). At survival analysis, the risk for a 1-point EDSS increase was slightly higher in group B than in group A (p = 0.053). Low-dose atorvastatin may be beneficial, as add-on therapy, in poor responders to high-dose interferon beta-1a alone.

Petrogenesis of coexisting SiO2-undersaturated to SiO2-oversaturated felsic igneous rocks: The alkaline complex of Itatiaia, southeastern Brazil

Abstract The Itatiaia alkaline complex is a Late Cretaceous intrusion (72 Myr) made up of felsic differentiates, with syenitic rocks dominant throughout and with presence of both nepheline- and quartz-rich varieties. Dykes with phonolitic or trachytic composition cross-cut the coarse-grained facies. The rocks are arranged concentrically, with the core of the complex being formed by SiO 2 -oversaturated syenites (with a small outcrop of granites), and are radially displaced by faults related to regional tectonic lineaments. The minerals show gradual but significant changes in composition (salitic and augitic to aegirine-rich pyroxenes, hastingsite and actinolite to richterite and arfvedsonite amphiboles, sodic plagioclase to orthoclase feldspars and so on) and the whole-rock trends are broadly consistent with fractional crystallization processes dominated by alkali feldspar removal. Sr-isotopic data indicate more radiogenic ratios for the SiO 2 -oversaturated rocks (0.7062-0.7067 against 0.7048-0.7054 for the SiO 2 -undersaturated syenites), consistent with small amounts of crustal input. The favored hypothesis for the petrogenesis of the different syenitic groups is the prolonged differentiation starting from differently SiO 2 -undersaturated mafic parental magmas (potassic alkali basalts to ankaratrites, present in the Late Cretaceous dyke swarms of the area), accompanied by variable crustal contamination prior to the final emplacement. The lack of carbonatite as a significant lithotype, the potassic affinity of the Itatiaia complex, and the relatively high Sr-isotopic ratios match the characteristics of the other complexes of the Rio de Janeiro-Sa˜o Paulo states coastline and confirm the ultimate derivation of these differentiated rocks from an enriched lithospheric mantle source.

The glycopeptide CSF114(Glc) detects serum antibodies in multiple sclerosis

Synthetic glycopeptides have the potential to detect antibodies in multiple sclerosis (MS). In the present study, we analyzed the antibodies (IgM class, IgG class and IgG subclasses) to the synthetic glycopeptide CSF114(Glc) in the serum of 186 MS patients, 166 blood donors (BDs), 25 patients affected by meningitis/encephalitis, 41 affected by systemic lupus erythematosus (SLE) and 49 affected by rheumatoid arthritis (RA). The IgM antibody level to CSF114(Glc) was significantly increased in MS patients versus BDs (p<0.001) or versus other autoimmune diseases (SLE or RA, p<0.001). The IgG response was restricted to the subclass IgG2. IgM antibodies to CSF114(Glc) were found in 30% of relapsing/remitting MS patients and, at lower levels, in subjects affected by meningitis/encephalitis. The study of antibodies to CSF114(Glc) is a new, potential immunological marker of MS.

The eruption of The Breccia Museo (Campi Flegrei, Italy): Fractional crystallization processes in a shallow, zoned magma chamber and implications for the eruptive dynamics

Abstract The Breccia Museo Member (BMM) was formed by an explosive eruption that occurred in the SW sector of Campi Flegrei about 20 ka ago. The eruptive sequence consists of the Lower Pumice Flow Unit and the overlying Upper Pumice Flow Unit with its associated lithic Breccia Unit. Interlayered with the Breccia Unit is a welded deposit that mainly consists of spatter clasts (Spatter Unit). The products of this eruption range in composition from trachytic to trachyphonolitic with K 2 O decreasing from 9.5 to 7 wt.%; Na 2 O correspondingly increases from 2.6 to 7.2 wt.% with increasing differentiation (Nb from 23 to 122 ppm). The phenocrysts are mostly sanidine (Or 88-63 ) with subordinate plagioclase (An 33-27 ), clinopyroxene (Ca 47 Mg 44 Fe 9 to Ca 46 Mg 35 Fe 19 ), biotite, titanomagnetite, and apatite. The observed major- and trace-element variations are fully consistent with about 80% fractional crystallization of a sanidine-dominated assemblage starting from the least differentiated trachytes. The compositions of the erupted products are compatible with the progressive tapping of a shallow magma chamber that was thermally and chemically zoned. The incompatible trace elements indicate a slightly different magma composition with respect to trachytes of the Campi Flegrei mainland. The geochemical stratigraphy suggests that after an early eruptive phase during which the upper, most differentiated level of the magma chamber was tapped, the sudden collapse of the roof of the reservoir triggered drainage of the remaining magma, which ranged in composition from trachyte to trachyphonolite, and formed the Breccia Unit and the Upper Pumice Flow Unit. The strongly differentiated trachyphonolite composition of the spatter clasts also suggests that they likely originated from the uppermost part of the reservoir soon after the eruption of Lower Pumice Flow Unit and the collapse of the chamber roof. This is in agreement with the eruptive model proposed by Perrotta and Scarpati (1994).

Petrogenetic significance of peralkaline rocks from Cenozoic calc-alkaline volcanism from SW Sardinia, Italy

Abstract The Tertiary volcanism of SW Sardinia is characterized by close field association of lower sequences characterized by calc-alkaline basaltic andesites, andesites and minor basalts (28.5 ± 1 to 17 ± 0.7 Ma) and by an upper sequence (up to 500 m thick) (mainly composed of ignimbrites) ranging from dacites to calc-alkaline rhyolites and comendites in the upper part (17.6 ± 0.8 to 13.8 ± 0.7 Ma). In this paper we focused on petrological aspects of the upper sequence in an attempt to understand the origin of peralkaline rocks generally characterizing intraplate volcanic settings (e.g., main Ethiopian rift) associated with rock series of transitional character. In Sardinia, comendites are associated with calc-alkaline rocks related with subduction of oceanic lithosphere. In this context, ignimbrites from the Northern sector have been interpreted as products of partial melting of continental crust. Five major groups were distinguished on the basis of stratigraphy, mineral assemblages, whole-rock and glass chemistry: 1. (a) G 1 dacites (Pl An68–42 + Opx + Cpx ± altered Ol and locally Pl An58–43 + Bt + Amph ± Opx ± Cpx); 2. (b) G 2 rhyodacites (Pl An46–29 + San Or66 + Opx + Cpx ± Ol ± Bt); 3. (c) G 3 rhyolites “ transitional ” to peralkaline rhyolites (Pl An40–26 + San Or55–42 ± Anor ± Opx ± Cpx); 4. (d) G 4 comendites (Na-San Or46–39 ± Anor + Qz + Na-Px + Na-Amph); 5. (e) G 5 post-comenditic rhyolites “ transitional ” to peralkaline rhyolites (Pl An26–24 + Na-San Or42–40 ± Anor). Ti-Mt + Ilm ± Ap appear to be the common accessory phases in all groups; however, Zir + Mt were also found in the G 3 and G 4 groups. Petrographic data and variation of chemical compositions of the main mineral phases (i.e. % An in plagioclases and Mg# in mafic minerals) suggest that the whole sequence is genetically related. Geothermometric and geobarometric calculations gave liquidus temperatures decreasing from G 1 to G 4 from 1100° to ∼950°C and pressures of ∼5–7 kbar. The latter should correspond to the depth of magma evolution for the investigated rocks. The agpaitic index increases with SiO 2 and shifts from subalkaline to peralkaline values at the transition from G 3 to G 4 . The chemical evolution observed in the upper sequence could be governed by dominant crystal/liquid fractionation processes of the observed mineral assemblage, leading to residual peralkaline liquids. Particularly, trace elements show a general enrichment of incompatible elements and a strong enrichment for Zr and Nb, accompanied by depletion of compatible elements (Sr and Ba). Furthermore, the chondrite-normalized rare-earth element (REE) diagram shows a comparable pattern characterized by a progressive REE enrichment from G 1 to G 4 with an increasing negative Eu anomaly, which confirms that feldspar is the dominant fractionating phase. Mass-balance calculations are consistent with a magmatic system dominated by crystal/liquid fractionation processes. This model confirms that the comendite rocks can be related with the subalkaline upper sequence from SW Sardinia. ( 87 Sr 86 Sr ) o at 16.5 and 15 Ma for subalkaline and peralkaline units in the upper sequence are 0.70750 and 0.70640, respectively, and are well comparable with the values for the andesites. This confirms that the whole sequence from the Sulcis area is genetically related and crystal/liquid fractionation was the dominant process in the evolution of the upper sequence.

Fingolimod versus interferon beta/glatiramer acetate after natalizumab suspension in multiple sclerosis

The comparative effectiveness of fingolimod versus interferon beta/glatiramer acetate was assessed in a multicentre, observational, prospectively acquired cohort study including 613 patients with relapsing multiple sclerosis discontinuing natalizumab in the Italian iMedWeb registry. First, after natalizumab suspension, the relapse risk during the untreated wash-out period and during the course of switch therapies was estimated through Poisson regression analyses in separated models. During the wash-out period an increased risk of relapses was found in patients with a higher number of relapses before natalizumab treatment (incidence rate ratio = 1.31, P = 0.0014) and in patients discontinuing natalizumab due to lack of efficacy (incidence rate ratio = 2.33, P = 0.0288), patients choice (incidence rate ratio = 2.18, P = 0.0064) and adverse events (incidence rate ratio = 2.09, P = 0.0084). The strongest independent factors influencing the relapse risk after the start of switch therapies were a wash-out duration longer than 3 months (incidence rate ratio = 1.78, P < 0.0001), the number of relapses experienced during and before natalizumab treatment (incidence rate ratio = 1.61, P < 0.0001; incidence rate ratio = 1.13, P = 0.0118, respectively) and the presence of comorbidities (incidence rate ratio = 1.4, P = 0.0097). Switching to fingolimod was associated with a 64% reduction of the adjusted-risk for relapse in comparison with switching to interferon beta/glatiramer acetate (incidence rate ratio = 0.36, P < 0.0001). Secondly, patients who switched to fingolimod or to interferon beta/glatiramer acetate were propensity score-matched on a 1-to-1 basis at the switching date. In the propensity score-matched sample a Poisson model showed a significant lower incidence of relapses in patients treated with fingolimod in comparison with those treated with interferon beta/glatiramer acetate (incidence rate ratio = 0.52, P = 0.0003) during a 12-month follow-up. The cumulative probability of a first relapse after the treatment switch was significantly lower in patients receiving fingolimod than in those receiving interferon beta/glatiramer acetate (P = 0.028). The robustness of this result was also confirmed by sensitivity analyses in subgroups with different wash-out durations (less or more than 3 months). Time to 3-month confirmed disability progression was not significantly different between the two groups (Hazard ratio = 0.58; P = 0.1931). Our results indicate a superiority of fingolimod in comparison to interferon beta/glatiramer acetate in controlling disease reactivation after natalizumab discontinuation in the real life setting.

Crystal chemistry of clinopyroxene from alkaline undersaturated rocks of the Monte Vulture Volcano, Italy

Abstract The Monte Vulture is a Late Pleistocene stratovolcano, composed of highly undersaturated alkaline potassic to ultrapotassic rocks belonging to the Roman Magmatic Province. These rocks are notably richer in Na2O if compared to similar rocks of the Roman Province. Two distinct magmatic Series have been recognized: (1) feldspar-bearing series, ranging from basanite to phonolite, and a volumetrically subordinate (2) feldspar-free series, consisting of melilitite, melafoidite, and hauynophyre. The clinopyroxene compositions of the feldspar-bearing series ranges from diopside to ferro-salite (hedenbergite), and shows, from basanite to phonotephrite, increasing FeOtot, Al2O3, and TiO2 and decreasing of MgO contents. Clinopyroxene in basanites and tephrites has generally high Fe3+ contents, which is typical for clinopyroxene from the Roman Province. Clinopyroxene of the feldspar-free series shows a more restricted variation in MgO, and has often very high Al2O3, FeOtot, and TiO2 contents. In all the crystals examined the Al3+ content is high and is present mostly on the T site and for a minor part on the M1 site. The M1–O2 distance shows a good correlation with the RM13+ content; clinopyroxene from basanites (feldspar-bearing series) has the lowest RM13+ and that from melilitite and hauynophyre (feldspar-free series) the highest RM13+ contents. Clinopyroxene crystals from feldspar-free rocks have smaller M1 and larger T polyhedral volumes when compared to those in olivine–melilitites and melilitites (kamafugites) from Umbria, but they show similar polyhedral volumes as clinopyroxene crystals from leucite-bearing rocks. Although clinopyroxene from feldspar-free rocks has small M1 volumes due to the high R3+ contents, M1 volumes of clinopyroxene from melilitites are larger than expected because of the higher (Fe3+/Al3+)M1 values. This larger M1 volume of clinopyroxene in melilitites causes a shortening of and a lengthening of the M2–O3 distance. Strong compositional and structural similarities between clinopyroxene of Monte Vulture and Leucite-bearing rocks of the Roman Province (plagioclase-bearing High Potassium Series=HKS) indicate a common petrogenetic affinity. On the other hand, differences between clinopyroxene in feldspar-free rocks from Monte Vulture and that in kamafugites (i.e, olivine melilitites, kalsilitites) from Central Italy, suggest significant magma dissimilarities between these two groups.