Base cation mobility in vineyard soils of the Colli Albani volcanic district (Central Italy)

The quality of the Colli Albani volcanic soils has certainly contributed to the vine cultivars hence the name of one of the oldest wines (i.e., Alban wine). The alkali up to 15 wt%, SiO2 ≤ 52 wt% and the emplacement at high temperature (≤ 600 °C) are the bedrock features that have deeply influenced the soil-forming processes in the vineyards. However, the peculiar features of the Colli Albani soils are not well known. Field survey and textural, mineralogical, and chemical data obtained with SEM, EMP, XRD, and ICP-OES were used to characterize the vineyard soils of the Colli Albani. Leucite (Lct)-bearing soils and quartz (Qz)-bearing soils occur in the studied vineyard. The Qz-bearing soils represent more weathered volcanic material, depleted in primary minerals and enriched in clays, which show a lower cation exchange capacity (CEC) than the Lct-bearing soils. CEC is a misleading definition for the Colli Albani soils because the base cation mobility in the vineyard is independent from clay mineral enrichment in the soil. Actually, the release of K, Na, Ca, and Mg depends by (i) the complete dissolution of leucite and analcime, (ii) the oxy-reaction affecting the phlogopite, which releases K + Mg, and (iii) the incongruent dissolution of clinopyroxene characterized by the “gothic texture.” This texture highlights the capacity of clinopyroxene to release Ca and Mg in volcanic soils. Quantification of the texture and abundance of the primary minerals are mandatory for the management of the vineyard soils in the Colli Albani and, in general, it is significative for the vineyards in volcanic areas

Metasomatism induced by alkaline magma in the upper mantle of northern Victoria Land (Antarctica): an experimental approach

Magma generation in the Ross Sea system is related to partial melting of strongly metasomatised mantle sources where amphibole most probably plays a crucial role. In this context, metasomatism induced by a mela-nephelinite melt in lithospheric mantle of the Mt. Melbourne Volcanic Province (northern Victoria Land – NVL, Antarctica) was investigated experimentally studying the effects of melt interaction with lherzolite at 1.5-2.0 GPa and T=975-1300°C, and wehrlite at 1.0 GPa and T=1050-1250°C. The experiments were designed to induce melt infiltration into the ultramafic rocks. The observed modifications in minerals are compared with those found in mantle xenoliths from NVL. The effects of metasomatic modifications are evaluated on the basis of run temperature, distance from the infiltrating melt and on the diffusion rates of chemical components. Both in lherzolite and wehrlite, clinopyroxene exhibits large compositional variations ranging from primary diopside to high Mg-Cr-(Na) augitic and omphacitic clinopyroxenes in lherzolite, and to low Mg and high Ti-Al-Fe-Na augites in wehrlite. Olivine (in wehrlite) and spinel (in lherzolite) also result compositionally modified, the former shows enrichments in Fe, the latter displays a higher Cr/(Cr+Al) ratio. The systematic variations in mineral compositions imply modifications of the chemistry of the infiltrating melt as recorded by the glass veinlets and patches observed in some charges. In experiments involving wehrlite paragenesis, the glass composition approaches that of melt patches associated to both amphibole-free and amphibole-bearing natural samples, and is related to olivine+clinopyroxene crystallisation coupled with primary clinopyroxene dissolution at the contact between the metasomatising melt and the solid matrix. Even if amphibole crystallisation was not attained in the experiments, we were able to explain the occurrence of amphibole in the natural system considering that in this case a hot metasomatising melt infiltrates a cooler matrix

Renal involvement in HCV related cirrhosis evidenced as glomerular and tubular derangement

Introduction and Aims: The relation between HCV infection and glomerular damage is well recognized, with evidences of negative impact on renal function. HCV replication in renal tubular cells on kidney biopsies has been reported but very limited data are available on HCV-mediated tubular damage. The aim of the study was to assess the presence of renal involvement (RI), glomerular or tubular, in patients with HCV cirrhosis. Methods: 98 patients with HCV cirrhosis Child Pugh-A were consecutively enrolled. Glomerular filtration rate (eGFR) was estimated with CKD-EPI 2009 equation. Urinary albumin/creatinine (ACR) and alpha1microglobulin/creatinine (a1MCR) ratios were calculated. Glomerular involvement was defined based on ACR>20μg/mg, tubular involvement based on a1MCR>14μg/mg plus fractional sodium excretion (FeNa)>1%. Urine concentration of Liver-type Fatty Acid-Binding Protein (L-FABP) and Kidney injury molecule-1 (KIM-1) were examined in morning midstream urine samples (ELISA) and the values normalized to urine creatinine concentration as expression of tubular derangement. Results: eGFR was ≥60 mL/min/1.73 m2 in 92 patients (93.8%) and between 45-59 mL/min/1.73 m2 in 6 patients (6.1%). Glomerular involvement was found in 19 patients (19.4%), tubular involvement in 31 patients (31.6%) and these co-occurred in 10 patients ( p=0.034). Patients with glomerular or tubular involvement, or both, considered as patients with RI, showed significantly lower eGFR values ( p=0.005) (Tab 1). A ROC curve was drafted and a cut point of 90 ml/min predicted RI (AUC: 0.700; sensitivity 63%, specificity 75%). Patients with RI were older, had higher ACR and a1MCR levels and exhibited a higher KDIGO stage (Tab 1). No association was found between RI and: HCV-RNA levels, liver stiffness and liver function tests. L-FABP and KIM-1 levels were significantly higher in patients with RI. Conclusions: Tubular and/or glomerular involvement is quite frequent in HCV cirrhotic patients, despite a normal eGFR. The evidence of tubular involvement suggests an alternative localization of HCV as renal disease

THE ITALIAN QUATERNARY VOLCANISM

The peninsular and insular Italy are punctuated by Quaternary volcanoes and their rocks constitute an important aliquot of the Italian Quaternary sedimentary successions. Also away from volcanoes themselves, volcanic ash layers are a common and frequent feature of the Quaternary records, which provide us with potential relevant stratigraphic and chronological markers at service of a wide array of the Quaternary science issues. In this paper, a broad representation of the Italian volcano-logical community has joined to provide an updated comprehensive state of art of the Italian Quaternary volcanism. The eruptive history, style and dynamics and, in some cases, the hazard assessment of about thirty Quaternary volcanoes, from the north-ernmost Mt. Amiata, in Tuscany, to the southernmost Pantelleria and Linosa, in Sicily Channel, are here reviewed in the light of the substantial improving of the methodological approaches and the overall knowledge achieved in the last decades in the vol-canological field study. We hope that the present review can represent a useful and agile document summarising the knowledege on the Italian volcanism at the service of the Quaternary community operating in central Mediterranean area

Diamondites: evidence for a distinct tectono-thermal diamond-forming event beneath the Kaapvaal craton

The petrogenesis and relationship of diamondite to well-studied monocrystalline and fibrous diamonds are poorly understood yet would potentially reveal new aspects of how diamond-forming fluids are transported through the lithosphere and equilibrate with surrounding silicates. Of 22 silicate- and oxide-bearing diamondites investigated, most yielded garnet intergrowths (n = 15) with major element geochemistry (i.e. Ca–Cr) classifying these samples as low-Ca websteritic or eclogitic. The garnet REE patterns fit an equilibrium model suggesting the diamond-forming fluid shares an affinity with high-density fluids (HDF) observed in fibrous diamonds, specifically on the join between the saline–carbonate end-members. The δ13C values for the diamonds range from − 5.27 to − 22.48‰ (V-PDB) with δ18O values for websteritic garnets ranging from + 7.6 to + 5.9‰ (V-SMOW). The combined C–O stable isotope data support a model for a hydrothermally altered and organic carbon-bearing subducted crustal source(s) for the diamond- and garnet-forming media. The nitrogen aggregation states of the diamonds require that diamondite-formation event(s) pre-dates fibrous diamond-formation and post-dates most of the gem monocrystalline diamond-formation events at Orapa. The modelled fluid compositions responsible for the precipitation of diamondites match the fluid-poor and fluid-rich (fibrous) monocrystalline diamonds, where all grow from HDFs within the saline-silicic-carbonatitic ternary system. However, while the nature of the parental fluid(s) share a common lithophile element geochemical affinity, the origin(s) of the saline, silicic, and/or carbonatitic components of these HDFs do not always share a common origin. Therefore, it is wholly conceivable that the diamondites are evidence of a distinct and temporally unconstrained tectono-thermal diamond-forming event beneath the Kaapvaal craton

Thermal evolution of the lithosphere in a rift environment as inferred from the geochemistry of mantle cumulates, Northern Victoria Land, Antarctica

Among the abundant mantle xenoliths carried by the Cenozoic alkaline basalts of northern Victoria Land, Antarctica, we have studied a suite of clinopyroxene-rich cumulates collected at Browning Pass (Mt. Melbourne Volcanic Province), ranging in composition from wehrlites to clinopyroxenites. Clinopyroxenes belonging to both the Cr-diopside (wehrlites) and Al-augite series (ol-clinopyroxenites and clinopyroxenites) all show convex-upward REE patterns. Modal and cryptic metasomatism has variably affected the xenoliths, accounting for amphibole replacement of clinopyroxene and/or selective enrichment in incompatible elements. Chemical features, along with O^Sr^Nd isotopic data, indicate that both the parental magmas and the metasomatizing melts are related to the Cenozoic magmatic activity and imply the role of at least two mantle components with distinct isotopic fingerprints.The positive covariation between d18Oolivine and the amount of modal olivine, and between d18Oolivine and olivine Fo content, suggest that during the fractionation of olivine and pyroxene, the parent magma experienced a change in O-isotope composition; a low-d18O melt component was not only added to the minerals during the metasomatic event but was also involved in the genesis of the parental melts. The Browning Pass cumulates are used to constrain the origin of the Antarctic Cenozoic magmatism from a heterogeneous mantle source whose depleted end-member is inferred to be the local lithospheric mantle, whereas the enriched end-member is represented by early metasomatic veins or domains emplaced into the depleted mantle during an amagmatic phase of rifting at the beginning of Ross Sea opening. Thermobarometric analysis of the process shows that the respective contribution to magma generation of the two end-members is related to the change of local thermal regime induced by an ‘edge effect’ in the mantle circulation at the lithospheric step between the thick East Antarctic craton and the thinned Ross Sea crust