Luisa De Capitani

Characterization of the Danube River sediments using the PMF multivariate approach

Chemical composition data for the Danube River and its tributaries sediments were analyzed using positive matrix factorization (PMF). The objective was to identify both natural and anthropogenic sources affecting Danube Basin. During the Joint Danube Survey 2 (JDS2) campaign 148 bottom sediments samples were collected. The following elements were analyzed using the X-ray fluorescence technique: Al, As, Ca, Cd, Cl, Co, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, P, Pb, S, Si, Ti, V and Zn. Mercury was determined by cold vapour atomic absorption spectrometry. Three factors were obtained considering the whole dataset (Danube and tributaries), identified as: (i) carbonate component characterized by Ca and Mg; (ii) alumino-silicate component dominated by Si and Al content and the presence of some metals attributed to natural processes; (iii) anthropogenic source identified by Hg, S, P and some heavy metals load. To better characterize the role of tributaries, the Danube and tributaries datasets, were also analyzed separately. The same three factor structures were identified in the Danube dataset. For the tributaries, a four-factor source model gave one further factor dominated by S and P, which could be attributed to the use of fertilizers in agriculture.

Trace element distribution in eclogites and their clinopyroxene/garnet pair a case study from Soazza (Switzerland)

Rare earth element (REE) abundances have been determined in six samples of metabasites from the Pennidic Adula nappe in the area of Soazza (Mesolcina Valley, Switzerland). The samples cover a broad range of mineralogical composition from eclogite to epidote amphibolite through symplectitic garnet amphibolite. The REE patterns do not vary significantly and indicate a common origin of these rocks as “normal” mid-ocean ridge basalts (N-MORB). Two main eclogitic phases, clinopyroxene (cpx) and garnet (grt), have also been analysed for REE and other trace elements (Sc, V, Cr, Co, Ni, Cu, Zn, Sr, Y, Zr). The incorporation of REE and most trace elements in structural sites of cpx and grt is in accordance with that expected mainly from an evaluation of site geometry, ionic radius and charge balance and is therefore dependent on the major-element composition of the host phases. The changes in cpx/grt partition coefficients (D i ) for HREE are particularly associated with the temperature condition of the equilibration of the pair.

Influence of soil mineralogy and chemistry on fungi and plants in a waste-rock dump from the Libiola mine (eastern Liguria, Italy)

This work illustrates the results of a multidisciplinary study aimed at understanding the relations among the mineralogy and chemistry of a sulphidic waste rock-dumps from the Libiola mine (eastern Liguria, Itlay) and the metal uptake by fungi and plants spontaneously growing in a flat part at the bottom of this dump. The soil of the studied dump is characterized by severe edaphic conditions, mainly represented by high concentration of several toxic metals (Cr, Cu, Co, Ni, and Zn), low pHs, paucity of nutrients (in particular P, Ca, and K) and presence of superficial Fe-rich hardpans. Despite these harsh environmental conditions, the studied waste rock dump has been progressively colonized by several plants of Pinus pinaster . We found that this species is able to cope with some of these limiting factors by completely avoiding toxic metals from its tissues. The success of Pinus pinaster colonization is mainly due to the presence of Telephora terrestris and Scleroderma polyrrhizum, ectomycorrhizic with pine. These fungi are also able to actively absorb in their basidiomata most of the potential toxic elements occurring in the mine spoil. The recognized absorption sequence Cu > Zn > Cr > Ni > Co obtained for these macrofungi well matches with the sequences resulted from water leaching tests and EDTA extractions. The results obtained in our work highlighted the importance of multidisciplinary studies to clarify the influence of mineralogical and chemical composition on metal accumulation or resistance by native plants and mycobiota in abandoned mining sites. This may also have important implications for fungi and plants potential use in future forestation programs on metal contaminated sites.

Phreatic sulphide bearing quartz breccias between crystalline basement and Collio formation (Southern Alps, Italy)

In this work a report is given of the geological, petrographic and ore mineralogical features of several sulphide-bearing quartz breccia (SQB) bodies outcropping in a structurally complex sector of the Orobic Alps (Southern Alpine domain) and close to the uranium-rich mining area of Novazza. Although little studied, these breccia bodies were previously attributed to different genetic processes and/or geological domains (e.g., Crystalline Basement, Basal Conglomerate formation). The features of the SQB bodies suggest a hydrothermal origin likely related to the large-scale hydrothermal process causing the formation of the nearby uranium ore deposit at Novazza.

Caratteri chimici e mineralogici del «vitrofiro di Gràntola» (Varese)

Rare outcrops of a glassy rock very similar to an obsidian occur among the Permian volcanics of the Lugano region, about 15 km North of Varese (Italy). Such a rock is known as «vitrofiro di Gràntola» (the «vitrophyric dacite» of Stille and Buletti, 1987, 262 Ma in age). XRF analyses for major and some trace elements performed on four selected samples indicate a rhyodacitic chemistry with a calcalkaline affinity for these rocks. Microprobe analyses of Mg-Fe and Fe-Mg-orthopyroxene, Fe-augite, Fe-pargasite, Fe-edenite, Fe-olivine, plagioclase, sanidine and allanite are given as a support for the pre-eruption differentiation history.RiassuntoCirca 15 km a Nord di Varese (Italia), si osservano limitati affioramenti di una roccia dall’aspetto vetroso, molto simile a quello di un’ossidiana, facente parte delle vulcaniti permiane del Luganese. Tale roccia, conosciuta come «vitrofiro di Gràntola», corrisponde allavitrophyric dacite datata 262 Ma da Stille e Buletti (1987). La composizione (determinata con XRF) in element! maggiori, minori ed in traccia di 4 campioni opportunamente selezionati, dimostra il loro carattere riodacitico con affinità calcalcalina. La composizione, determinata alla microsonda elettronica, dei minerali femici (orto-e clinopirosseni, anfiboli, olivine), sialici (plagioclasi e sanidino) e di un’allanite ha fornito un contribute) alla comprensione del processo evolutivo precedente alla messa in posto.

Cummingtonite nelle plutoni ti della Val Blandino (Como)

Cummingtonite occurs in the marginal rind of the Val Biandino intrusion (Orobic Alps, Como, Italy), both as the only amphibole phase in association with pyroxene, and as linked to calcian amphiboles of different types. Crystalchemical data point out the relationship of cummingtonite with the early stage of intrusion of the Val Biandino masses.RiassuntoViene segnalata la presenza di cummingtonite sia come unico anfibolo, associato talora a pirosseni, sia concresciuta con Ca-anfiboli in zone marginali, prevalentemente gabbrodioritiche, delle plutoniti della Val Biandino. Ľinterpretazione dei dati cristallochimici ha permesso di chiarire il significato di questo minerale in relazione alle ipotesi di messa in posto ed evoluzione delle plutoniti stesse.