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This contribution describes a geodatabase structure designed to manage a large amount of geo-environmental data for the "Gronda di Genova" highway by-pass tunnels in Liguria region (Italy). In particular, an innovative dataset structure founded on an explicit conceptual model was designed to represent the distribution of petrofacies containing Natural Occurring Asbestos (NOA), and their minero-chemical composition. This in order to assess the environmental risk (air dispersion of fibers) due to the tunnel excavation in the asbestos-bearing rocks. Problems related to the GIS (shp) - AutoCAD (layer) conversion have been also considered for delivering the graphic layout of the project and are here discussed.

This paper describes lithostratigraphy and Alpine tectono-metamorphic evolution of the oceanic succession of the Monte Banchetta-Punta Rognosa unit (Italian Western Alps). The oceanic substratum consists of serpentinized peridotites covered by ophicarbonates, documenting therefore exhumation and exposure of the upper mantle at the seafloor in Jurassic times. Upwards, the sedimentary cover begins with polymictic metabreccias and intercalated siliciclastic sediments (considered Late Jurassic - Early Cretaceous in age), both containing oceanic and continental detritus, and interpreted as mass-flow deposits on sea floor. Then, the upper part of the cover consists of Cretaceous pelagic carbonate sediments (calcschists), lying over a main unconformity. The stratigraphic features and the architecture of the sedimentary cover suggest that this segment of the Piemonte-Liguria Ocean was in a proximal position with respect to the rifted margins. In a general context of the ocean-continent transition, source areas for continental detritus can be envisaged on the hyperextended part of the European margin or on its more proximal part, adjacent to structural highs made of oceanic mantle, as recorded by oceanic detritus. The combination of structural, petrographic and mineral chemistry data defined the Alpine prograde and retrograde metamorphic evolution of this oceanic segment. The metamorphic peak was reached during the D1 event at the transition between lawsonite- and epidote- blueschist facies conditions. Then, a first decompressional event D2 always at blueschist facies conditions was followed by a D3 event at green schist facies conditions.

The pressure, temperature, and timing (P-T-t) conditions at which CO2 was produced during the Himalayan prograde metamorphism have been constrained, focusing on the most abundant calc-silicate rock type in the Himalaya. A detailed petrological modeling of a clinopyroxene + scapolite + K-feldspar + plagioclase + quartz ± calcite calc-silicate rock allowed the identification and full characterization – for the first time – of different metamorphic reactions leading to the simultaneous growth of titanite and CO2 production. The results of thermometric determinations (Zr-in-Ttn thermometry) and U-Pb geochronological analyses suggest that, in the studied lithology, most titanite grains grew during two nearly consecutive episodes of titanite formation: a near-peak event at 730–740 °C, 10 kbar, 30–26 Ma, and a peak event at 740–765 °C, 10.5 kbar, 25–20 Ma. Both episodes of titanite growth are correlated with specific CO2-producing reactions and constrain the timing, duration and P-T conditions of the main CO2-producing events, as well as the amounts of CO2 produced (1.4–1.8 wt% of CO2). A first-order extrapolation of such CO2 amounts to the orogen scale provides metamorphic CO2 fluxes ranging between 1.4 and 19.4 Mt/yr; these values are of the same order of magnitude as the present-day CO2 fluxes degassed from spring waters located along the Main Central Thrust. We suggest that these metamorphic CO2 fluxes should be considered in any future attempts of estimating the global budget of non-volcanic carbon fluxes from the lithosphere.

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In order to promote geosite conservation in the project entitled 'PROactive management of GEOlogical heritage in the PIEMONTE Region', we propose a comprehensive study involving the Monviso Massif (MM) geothematic area, one of the most outstanding symbols of the Alps and particularly of the Cottian Alps. Specifically, at the MM, the inventory of a number of different geosites whose conservation and development require different geologic and some additional non-geological expertise is considered: (1) some of the best preserved ophiolites in the Alps and the associated Cu-Fe mineralizations; (2) the lithostructural units in the Germanasca Valley; (3) the first primary source of jade in the Alps at the MM and its importance in terms of Neolithic to Bronze Age-polished stone implements; (4) the world-famous minerals such as coesite and giant pyrope, as well as type localities for new minerals (including carlosturanite); (5) the area, now buried under a debris flow, where Hannibal is thought to have regrouped his army while crossing the Alps; and (6) the biodiversity of lichens, microfungi and cyanobacteria colonizing the ophiolites, which can give additional value for the environmental assessment and evaluation of the MM outcrops. Following geodiversity identification, further stages will be devoted to develop appropriate plans for geodiversity conservation in this area.

The Gosainkund–Helambu region in central Nepal occupies a key area for the development of Himalayan kinematic models, connecting the well-investigated Langtang area to the north with the Kathmandu Nappe (KN), whose interpretation is still debated, to the south. In order to understand the structural and metamorphic architecture of the Greater Himalayan Sequence (GHS) in this region, a detailed petrological study was performed, focusing on selected metapelite samples from both the Gosainkund–Helambu and Langtang transects. The structurally lowest sample investigated belongs to the Lesser Himalayan Sequence; its metamorphic evolution is characterized by a narrow hairpin P–T path with peak P–T conditions of 595 ± 25 °C, 7.5 ± 1 kbar. All of the other samples here investigated belong to the GHS. Along the Langtang section, two tectono-metamorphic units have been distinguished within the GHS: the Lower Greater Himalayan Sequence (L-GHS), characterized by peak P–T conditions at 728 ± 11 °C, 10 ± 0.5 kbar (corresponding to a T/depth ratio of 22 ± 1 °C km−1), and the structurally higher Upper Greater Himalayan Sequence, with peak metamorphic conditions at 780 ± 20 °C, 7.8 ± 0.8 kbar (corresponding to a T/depth ratio of 31 ± 4 °C km−1). This confirms the existence of a main tectono-metamorphic discontinuity within the GHS, as previously suggested by other authors. The results of petrological modelling of the metapelites from the Gosainkund–Helambu section show that this region is entirely comprised within a sub-horizontal and thin L-GHS unit: the estimated peak metamorphic conditions of 734 ± 19 °C, 10 ± 0.8 kbar correspond to a uniform T/depth ratio of 23 ± 3 °C km−1. The metamorphic discontinuity identified along the Langtang transect and dividing the GHS in two tectono-metamorphic units is located at a structural level too high to be intersected along the Gosainkund–Helambu section. Our results have significant implications for the interpretation of the KN and provide a contribution to the more general discussion of the Himalayan kinematic models. We demonstrate that the structurally lower unit of the KN (known as Sheopuri Gneiss) can be correlated with the L-GHS unit; this result strongly supports those models that correlate the KN to the Tethyan Sedimentary Sequence and that suggest the merging of the South Tibetan Detachment System and the Main Central Thrust on the northern side of the KN. Moreover we speculate that, in this sector of the Himalayan chain, the most appropriate kinematic model able to explain the observed tectono-metamorphic architecture of the GHS is the duplexing model, or hybrid models which combine the duplexing model with another end-member model.

Metamorphic degassing from active collisional orogens supplies a significant fraction of CO2 to the atmosphere, thus playing a fundamental role even in today's Earth carbon cycle. Appealing clues for a contemporary metamorphic CO2 production in active orogens are represented by the widespread occurrence, along the whole Himalayan belt, of CO2 rich hot-springs mainly localized along major tectonic discontinuities. In contrast to these well-studied hot-springs, almost no chemical and isotopic data are actually available for cold-springs, especially for those located at high-altitude and in remote areas of the Himalayas. In the framework of the Ev-K2-CNR SHARE (Stations at High Altitude for Research on the Environment) Project, we have started a preliminary chemical and isotopic study on high-altitude cold-springs located at different structural levels in the eastern Nepal Himalayas. Chemical and isotopic data obtained from the high-altitude cold-springs are compared with those obtained by previous authors from hot-springs located along the MCT. The isotopic signature of stable isotopes of hydrogen and oxygen could help to identify the waters sources in the investigated Himalayan sectors, to individuate mixing phenomena between waters of different provenience and possible connection with different circulation nets. These first measurements on high-altitude springs from remote areas of eastern Nepal represent a first step towards a better definition of a reliable scenario of water resources availability and will contribute to the understanding of the water cycle in the studied area.

This paper describes a 11-days field trip along the Numbur Cheese Circuit (NCC), running along the Khimti Khola and Likhu Khola valleys in central-eastern Nepal Himalaya. The purpose of this guide is to introduce the most interesting geological aspects of this sector of the Himalaya through observations of selected outcrops, samples and view-points along the NCC. The NCC trek crosses a thick portion of the Greater Himalayan Sequence (GHS), divided into a lower (GHS-L) and an upper (GHS-U) portion. Along this path, the GHS-L consists of Grt ± St ± Ky -bearing two-micas micaschist, associated to metric to decametric -thick levels of two-micas quartzitic gneiss, Grt + Zo granofels and small lenses of impure marble. In its lower structural levels, the GHS-L shows intercalations of phylladic Ank-bearing micaschist (+ greenish Bt), whereas in the uppermost structural levels evidence of partial melting are locally observed. Upwards, the GHS-U (corresponding to the Higher Himalayan Crystallines) consists of Grt + Bt + Kfs + Ky/Sil anatectic paragneiss (i.e. Barun Gneiss) and Kfs + Bt + Sil ± Grt paragneiss (i.e. Black Gneiss) characterized by Qtz + Sil nodules. Metric to plurimetric -thick layers of calc-silicate granofels and impure marble are locally intercalated. Networks of leucogranitic and pegmatitic dikes occur in the upper structural levels of the GHS-U, and are spectacularly exposed in the highest peaks. From a structural point of view, in the NCC area, the GHS is dominated by lithological boundaries and foliations dipping towards the north. The Main Central Thrust Zone, namely the shear zone related to the exhumation of the high-grade GHS on the lower Lesser Himalayan Sequence (LHS), is roughly centered on the intensively top-to-the-S sheared GHS-L. Locally, evidences of late top-to-the-NE extension has been observed in the GHS-L.

The Monviso Ophiolite (MO) in the Italian Western Alps is one of the best known relics of oceanic crust in the orogen. Moreover, it is one of the strategic areas chosen to represent the geodiversity of Piemonte Region (Rolfo et al. 2014). The MO gives the chance to see and appreciate different portions of the ancient ocean along a relatively short mountain trail; from the Po river springs at Pian del Re, a path from 2000 m up to about 2350 m a.s.l. shows all different ophiolitic lithologies - modified after the Alpine evolution - within few kilometers.

Cordierite-bearing anatectic rocks inform our understanding of low-pressure anatectic processes in the continental crust. This article focuses on cordierite-bearing lithologies occurring at the upper structural levels of the Higher Himalayan Crystallines (eastern Nepal Himalaya). Three cordierite-bearing gneisses from different geological transects (from Mt Everest to Kangchenjunga) have been studied, in which cordierite is spectacularly well preserved. The three samples differ in terms of bulk composition likely reflecting different sedimentary protoliths, although they all consist of quartz, alkali feldspar, plagioclase, biotite, cordierite and sillimanite in different modal percentages. Analysis of the microstructures related to melt production and/or melt consumption allows the distinction to be made between peritectic and cotectic cordierite. The melt productivity of different prograde assemblages (from two-mica metapelite/metagreywacke to biotite-metapelite) has been investigated at low-pressure conditions, evaluating the effects of muscovite v. biotite dehydration melting on both mineral assemblages and microstructures. The results of the thermodynamic modelling suggest that the mode and type of the micaceous minerals in the prograde assemblage is a very important parameter controlling the melt productivity at low-pressure conditions, the two-mica protoliths being significantly more fertile at any given temperature than biotite gneisses over the same temperature interval. Furthermore, the cordierite preservation is promoted by melt crystallization at a dry solidus and by exhumation along P-T paths with a peculiar dP/dT slope of about 15-18 bar °C-1. Overall, our results provide a key for the interpretation of cordierite petrogenesis in migmatites from any low-P regional anatectic terrane. The cordierite-bearing migmatites may well represent the source rocks for the Miocene andalusite-bearing leucogranites occurring at the upper structural levels of the Himalayan belt, and low-P isobaric heating rather than decompression melting may be the triggering process of this peculiar peraluminous magmatism.