French-Italian Alps Research Articles

Simplified assessment of the seismic vulnerability of small earth dams

The seismic performance of earth dams is usually assessed based on the expected crest displacements induced by the soil densification and the triggering of sliding mechanisms. Nevertheless, a proper evaluation of the seismic response of the dams generally involves the use of advanced constitutive models able to reproduce the dynamic soil response. The calibration of the constitutive parameters is however a nontrivial task, as it requires a deep understanding of the mechanical response of the materials. When dealing with small earth dams, budget constraints often prevent a reliable geotechnical characterization of the soils, limiting in the common practice the applicability of dynamic numerical simulations. The performance of the dams is therefore assessed, at least at a preliminary level, by employing simplified empirical relationships that link a seismic intensity measure to the expected crest settlement. This study fits within this framework, presenting the results of the ReSba European project for the French-Italian Alps area. Two small earth dams, object of extensive geophysical and geotechnical surveys, are selected based on a first-level screening methodology. Advanced fully-coupled numerical simulations are performed to investigate the seismic response of the dams. The results of the analyses are then compared to predictions obtained by employing empirical relationships to show the abilities, and the potential drawbacks, of the simplified relationships.

The Production of a Landscape by and for Skiing – A History of Winter Sports Resorts in the French-Italian Alps through the Work of the Architect and Town Planner Laurent Chappis

La présente contribution interroge, à travers un regard historique, les interrelations entre la conception des stations touristiques nouvelles et la transformation des paysages de haute montagne. En effet, la création des stations de ski ne s’est pas uniquement concrétisée par l’implantation d’édifices et d’infrastructures en haute altitude. Tout au contraire, diverses composantes de l’environnement telles que la forêt, la morphologie du sol, l’hydrographie ont été modifiées. Par ailleurs, les caractères à la fois biophysiques et historiques des sites d’implantation ont influencé les processus de conception et de construction des stations de haute altitude. Nous adoptons comme angle d’observation et comme fil conducteur le parcours professionnel de l’urbaniste et architecte Laurent Chappis (1915-2013), qui permet d’explorer divers cas d’étude dans les Alpes franco-italiennes, à partir des années 1940 et jusqu’aux années 1980. Nous voulons comprendre les méthodes et les outils empruntés par l’architecte dans la définition des plans des stations, les éléments qui participent à la construction d’un paysage, l’évolution à la fois de l’approche de l’architecte et des plans. Par une relecture de l’histoire, nous parvenons à une réflexion sur les rapports entre projet et environnement dans les terres de haute altitude.

Environmental History, The History of Tourism in the Mountains and the Construction of New Knowledge: A Study of the Architecture of Winter Sports Resorts in the French-Italian Alps

Environmental history is a rapidly developing field of study. In keeping with the ecological, energy and health issues that affect contemporary societies, it is important to understand the past by examining the interactions between human and natural factors. This interest is particularly evident in work on the Alps and mountains in general. Our contribution relates and adds to studies focused on the history of tourism in the Alps and assesses the capacity of environmental history to produce a renewed knowledge. Moreover, it investigates the specificity of the Alps and the mountains as a privileged field of study for environmental history. After outlining recent scientific output from around the world based on environmental history, we present the results obtained through a research experiment on the history of winter sports resorts in the French-Italian Alps. Understanding the relationships between the evolution of the projects and the natural and historical components of the sites where they are located and extending the spatial and temporal frameworks of the analyses and the use of multiple sources will clarify how tourism develops in high-altitude areas. Our work invites researchers to move beyond the image of infrastructure built “ex nihilo” or on so-called “virgin” sites and a narrative limited to the period of the “Trente Glorieuses” to reveal the dynamics of how a territory transforms over time.

‘Along Footpaths over Snow-Covered Mountains…’ Historical Perspectives on Migration Journeys across the France–Italy Border (1945-1960)

The goal of this article is to examine the processes that (both legal and illegal) migration flows across the French-Italian Alps entailed between 1945 and 1960, a period that covers the last big wave of Italian emigration to France. Beyond the analysis of public policies aimed at selecting and managing “desirable migrants”, the study of individual journeys made through a cross-border micro-area – that is, the Aosta and Suse valleys, Beaufortain, Brianconnais and Maurienne – enriches our understanding of mobility phenomena. Special care is taken to show, through eyewitness accounts, the experiences of people involved in the migration.

The SuperNEMO demonstrator double beta experiment

The SuperNEMO experiment will study 82Se to look for neutrinoless double beta decays (0νββ), proof of the Majorana nature of neutrinos. SuperNEMO inherits the tracking-calorimetry technique of NEMO-3, allowing for a clear determination of event kinematics, while aiming for an improved background suppression and 0νββ sensitivity. A demonstrator module is currently starting operation. The ββ emitting source, ∼7 kg of 82Se in thin foils, is surrounded by a 0.5 meter long helium tracking chamber with 2000 Geiger cells. A 4π gamma catcher and electron calorimeter, made of plastic scintillators with an energy resolution of 7.8% (FWHM) at 1 MeV, surrounds the tracker. The ultra low radioactivity demonstrator is constructed and installed in the Modane Underground Laboratory in the Frejus Tunnel under the French–Italian Alps.

Long-term changes in alpine pedogenetic processes: Effect of millennial agro-pastoralism activities (French-Italian Alps)

Human activities are known to modify soil properties; however, the associated modifications to soil processes are poorly documented, as they must be studied over long time scales. Lake Verney, which is on the Italian side of the Petit Saint-Bernard Pass in the French-Italian Alps (2188ma.s.l.) provides a sediment record of the last 11,000cal.yrs BP. Analysis of multiple proxies within this sediment sequence, including sedimentological characteristics, mineral geochemistry (as determined using XRF and extractable Fe fractions), pollen and non-pollen palynomorphs (NPPs) and sediment DNA (sedDNA) analysis, is compared with analyses of current soils and paleosols within this mountain ecosystem in order to understand the main drivers of long-term pedogenesis. We performed principle component analysis on both the sediment proxies and the soil geochemical properties to identify different sediment endmembers that reflect different types of soil horizons, mainly stagnic and spodic. These horizons are characteristic of specific soil processes and their associated land uses.During the first part of the Holocene, a decrease in the carbonate fraction in the sediment reflects the loss of carbonate material from soils that occurred as early as postglacial vegetation became established. The migration of Fe-complexes until 6000cal.yrs BP indicates the development of Podzols in the catchment. The first signs of human land use are detected at 4300cal.yrs BP according to analyses of sedDNA and NPPs. Increases in the input of terrestrial organic matter, associated with forest clearance suggests degradation of the surface horizons of the Podzols. Erosion increased during the Roman Period due to sheep grazing. Then, while erosion was still increasing, Podzols developed into Stagnosols after the Middle Ages with cow grazing which is consistent with the current functioning of the soils. The history of the paleosols and archaeological stratigraphy within the study area confirm the model of soil evolution inferred from the lake sediments and allow us to characterize the human-induced “metapedogenetic phase” of the evolution of the soil cycle. Anthropo-pedogenesis may define the development of soils during the Anthropocene. The main consequence of this change in the functioning of the soils is a reduced sequestration of soil carbon.

Fault mechanics at the base of the continental seismogenic zone: Insights from geochemical and mechanical analyses of a crustal-scale transpressional fault from the Argentera crystalline massif, French–Italian Alps

Faulting mechanics is examined by combining geochemical and mechanical analyses from a key exposure of a major fault zone crossing the Argentera crystalline massif (French–Italian Alps). The analyses are carried out on co-genetic and syn-tectonic quartz and chlorite extension veins and shear veins associated with late stage deformation in the fault zone. Paleothermometry based on chlorite compositions gives formation temperatures of 300 °C ± 20 °C, that is near the base of the seismogenic zone. δ18O values of quartz and δD and δ18O values of chlorite indicate that veins crystallized from a metamorphic fluid. In parallel, a mechanical analysis based on the Mohr-Coulomb theory shows that the pore fluid factor λv required to simultaneously reactivate the studied fault and to open the extension veins was close to a lithostatic value (λv ∼ 1).Comparisons with the 2003–2004 Ubaye seismic swarm, having occurred in the continuity of the studied fault zone, suggest that the base of the seismogenic zone may act as a limit separating an upper permeable reservoir saturated with meteoric waters under hydrostatic to supra-hydrostatic pressures from a lower low-permeability reservoir containing metamorphic waters under lithostatic pressure. This study suggests that overpressured fluids can be released upwards in the brittle crust by shear-enhanced permeability and can trigger earthquakes.

New insight into late glacial vegetation with sedimentary ancient DNA (sedaDNA)

Human activities are known to modify soil properties; however, the associated modifications to soil processes are poorly documented, as they must be studied over long time scales. Lake Verney, which is on the Italian side of the Petit Saint-Bernard Pass in the French-Italian Alps (2188 m a.s.l.) provides a sediment record of the last 11,000 cal. yrs BP. Analysis of multiple proxies within this sediment sequence, including sedimentological characteristics, mineral geochemistry (as determined using XRF and extractable Fe fractions), pollen and non-pollen palynomorphs (NPPs) and sediment DNA (sedDNA) analysis, is compared with analyses of current soils and paleosols within this mountain ecosystem in order to understand the main drivers of long-term pedogenesis. We performed principle component analysis on both the sediment proxies and the soil geochemical properties to identify different sediment endmembers that reflect different types of soil horizons, mainly stagnic and spodic. These horizons are characteristic of specific soil processes and their associated land uses.During the first part of the Holocene, a decrease in the carbonate fraction in the sediment reflects the loss of carbonate material from soils that occurred as early as postglacial vegetation became established. The migration of Fe-complexes until 6000 cal. yrs BP indicates the development of Podzols in the catchment. The first signs of human land use are detected at 4300 cal. yrs BP according to analyses of sedDNA and NPPs. Increases in the input of terrestrial organic matter, associated with forest clearance suggests degradation of the surface horizons of the Podzols. Erosion increased during the Roman Period due to sheep grazing. Then, while erosion was still increasing, Podzols developed into Stagnosols after the Middle Ages with cow grazing which is consistent with the current functioning of the soils. The history of the paleosols and archaeological stratigraphy within the study area confirm the model of soil evolution inferred from the lake sediments and allow us to characterize the human-induced “metapedogenetic phase” of the evolution of the soil cycle. Anthropo-pedogenesis may define the development of soils during the Anthropocene. The main consequence of this change in the functioning of the soils is a reduced sequestration of soil carbon.

Reappraisal of the 1887 Ligurian earthquake (western Mediterranean) from macroseismicity, active tectonics and tsunami modelling

Early in the morning of 1887 February 23, a damaging earthquake hit the towns along the Italian and French Riviera. The earthquake was followed by a tsunami with a maximum run-up of 2 m near Imperia, Italy. At least 600 people died, mainly due to collapsing buildings. This ‘Ligurian earthquake’ occurred at the junction between the southern French—Italian Alps and the Ligurian Basin. For such a historical event, the epicentre and the equivalent magnitude are difficult to characterize with any degree of precision, and the tectonic fault responsible for the earthquake is still under debate today. The recent MALISAR marine geophysical survey allowed the identification of a large system of active faults. We propose that the rupture of some of the segments belonging to this 80-km-long northern Ligurian Faults system connected to a shallow-dipping major thrust plane at depth was the source of the 1887 Ligurian earthquake. We investigated the macroseismic data from the SISFRANCE-08 and DBMI-04 historical databases using several models of intensity attenuation with distance and focal depth. The modelling results are consistent with the off-shore location, with an epicentre around 43.70°–43.78°N and 7.81°–8.07°E, and with a magnitude Mw in the range of 6.3–7.5. Numerous earthquake source scenarios have been tested on the tide gauge record at Genoa harbour. As a result, we present seven characteristic source earthquake scenarios for a shallow strong earthquake occurring below the northern Ligurian margin. The modelled tide gauge records were analysed with the help of basic statistical tools and a simple harmonic analysis, to extract the wave spectrum characteristics. This analysis indicates that scenarios of a magnitude Mw of 6.8–6.9 along a reverse N55°E striking fault are the best candidates to explain the known characteristics of the tsunami that followed. The best-fitting scenarios comprise a 70°-dipping southward fault plane with Mw 6.8 and a 16°-dipping northward fault plane with Mw 6.9, both with reverse kinematics. Taking into account the geometry of the active faults, the location of the macroseismic epicentre and the morphotectonic evolution of the continental slope, we propose that the 1887 Ligurian earthquake corresponded to the reverse faulting of a N55°E striking fault plane dipping to the north with a coseismic slip of 1.5 m.

Dating the Tethyan Ocean in the Western Alps with radiolarite pebbles from synorogenic Oligocene molasse basins (southeast France)

For the first time in the Western Alps, radiolarite pebbles collected from Tertiary foreland molasse conglomerates are treated for microfossil extraction and dated. Among forty pebbles collected in the field, seven of them released diagnostic radiolarian assemblages ranging in age from Late Bajocian–Early Callovian to Middle Oxfordian–Early Tithonian. These ages overlap previous biochronological data obtained from in situ localities of the Schistes Lustrés Piemont zone of the French-Italian Alps and triple the number of diagnostic radiolarite samples known so far in this segment of the chain. The diagnostic pebbles are characterized by low grade metamorphism, showing that some eroded thrust-sheets from the oldest parts of the ocean escaped any tectonic burial during the Alpine convergence. Mixing of low and high-grade radiolarites, mafics and ultramafics pebbles implies that various ocean-derived units were exposed. This tectonic scenario involves tight refolding and severe uplift of the Eocene subduction wedge in the Early Oligocene.

Reactivation of a strike-slip fault by fluid overpressuring in the southwestern French-Italian Alps

A crustal-scale N130°E strike-slip fault in the Ubaye-Argentera area, southwestern French-Italian Alps, was the locus of a seismic swarm in 2003-2004. Its reactivation is examined by a 2-D frictional fault analysis. The regional stress tensor in the vicinity of the fault is determined by inversion of focal mechanisms of the 38 events with largest magnitudes of the 2003-2004 swarm. Inversion shows that the axis of the maximum principal stress σ1 is oriented nearly horizontal and at 63° from the fault plane and that the intermediate principal stress σ2 is almost parallel to the fault plane. A 2-D analysis with a static coefficient of friction of 0.4 (consistent with the presence of phyllosilicate-rich gouges at depth) shows that the N130°E fault is unfavourably oriented and that its reactivation is possible only with pore fluid pressure excess in the hypocentral region (6-7 km below surface). A calculation based on a pore fluid factor-differential stress failure mode diagram shows that the required excess pressure is comprised between 7 and 26 MPa. The presence of thermal springs in the Argentera area indicates that the pore fluid is water. The pore water overpressure is likely achieved by fault zone compaction and hydraulic barriers. The hydraulic barriers can be provided by hydrothermal sealing of the fault damage zone and by the 1-2-km-thick sedimentary lid (marl-rich autochtonous sedimentary cover and Embrunais-Ubaye sedimentary nappes) whose permeability is lower than that of the underlying crystalline rocks.

Alpine ocean seafloor spreading and onset of pelagic sedimentation: new radiolarian data from the Chenaillet-Montgenèvre ophiolite (French-Italian Alps)

Radiolarians of Middle Jurassic age (tentatively middle Bathonian) provide the first direct age determination from oceanic sediments associated with the Chenaillet-Montgenèvre ophiolite (Piemonte zone, French-Italian Alps). This datum obtained from radiolarites of the Lago Nero- Replatte thrust sheet is older than those previously established on ophiolite sedimentary covers from this segment of the western Alps. It also shows that Lago Nero-Replatte basal radiolarites are anterior to the youngest intrusives from the overlying Chenaillet s.s. thrust sheet. This chronological relationship implies either a late seafloor spreading-related magmatic activity in places younger than adjacent initial pelagic sedimentation, or more likely that the Lago Nero-Replatte and the Chenaillet s.s. thrust sheets are distinct and distant pieces of lithosphere that were eventually stacked together: the Lago Nero-Replatte unit was trapped within the accretionary wedge while the Chenaillet s.s., of a younger age and in a more distal position with regards to the European margin, was obducted. Regionally, the Lago Nero-Replatte sediments appear to be coeval to other Bathonian supraophiolitic radiolarites exposed in the western Alps. These results strengthen the Bathonian correlation of widespread seafloor spreading in both western Tethys and the central Atlantic ocean.

Drainage network geometry versus tectonics in the Argentera Massif (French–Italian Alps)

The Argentera Massif (French–Italian Alps), with its uniform lithology, was selected to evaluate how known Plio–Pleistocene tectonics have conditioned the drainage network geometry. The drainage network was automatically derived and ordered from a 10 m-resolution DEM. On hillshade images, alignments of morphological features were identified. The Massif was subdivided into 22 domains of 50 km 2 within which the directions of every river channel segment and the direction of the aligned morphological features were compared and contrasted with the strike of tectonic structures measured in the field. Results suggest that the Argentera drainage system is variously controlled by recent tectonics, depending on the Massif sector taken into account. In the NW sector, the vertical uplift is less because the strain has been accommodated in an oblique direction along a lateral thrust. In the SE sector, strain in a predominantly vertical direction along a frontal thrust has resulted in a major vertical displacement. Accordingly, the NW sector is characterized by (i) a strong geometric relationship between the main tectonic structures and the directions of river channels, (ii) longitudinal main rivers bordering the Massif, and (iii) a general trellis pattern within the domains. In the SE sector, the prolonged uplift has forced an original longitudinal drainage system to develop as a transverse system. This change has occurred by means of fluvial captures that have been identified by the presence of windgaps, fluvial elbows and knickpoints. At the domain scale, intense uplift of the SE sector has prompted the drainage pattern to evolve as a dendritic type with no clear influence of structure in the channel orientations.

The Eocene unconformity of the Briançonnais domain in the French—Italian Alps, revisited (Marguareis massif, Cuneo); a hint for a Late Cretaceous—Middle Eocene frontal bulge setting

The tectonic significance of the Eocene unconformity in the Briançonnais domain, classically regarded as recording a compressional event, is re-evaluated, based on field studies in the Marguareis massif, Maritime-Ligurian Alps. In this external, weakly metamorphic Briançonnais unit, we describe N-trending, folded paleo-normal faults. These paleofaults operated during the Late Cretaceous-Late Eocene, and control both the thickness of the Senonian-Paleocene calcschists and the distribution of the disconformable Middle Eocene-Early Priabonian formations, i.e. the channelised, resedimented Nummulitic limestones, associated with sandy turbidites, and the sandy- calcareous Lower Flysch Noir. The chaotic Upper Flysch Noir (Priabonian), which includes olistoliths from the Helminthoid Flysch nappes, disconformably overlies the Late Cretaceous-Middle/Late Eocene levels. At the scale of the whole Briançonnais domain of the French-Italian Alps, the superimposed Senonian-Eocene disconformities would indicate extensional faulting and block tilting, associated with a regional uplift which caused emersion of part of the domain (most internal Briançonnais, Corsica). Extension and coeval uplift would record the crossing of the frontal flexure (external bulge) of the European/Briançonnais lower plate situated west of the Alpine subduction zone between 80–70 Ma and ∼40 Ma, i.e. before the subduction of the Briançonnais plateau around 38–35 Ma. © 2002 Éditions scientifiques et médicales Elsevier SAS. All rights reserved.

The Eocene unconformity of the Briançonnais domain in the French–Italian Alps, revisited (Marguareis massif, Cuneo); a hint for a Late Cretaceous–Middle Eocene frontal bulge setting

The tectonic significance of the Eocene unconformity in the Briançonnais domain, classically regarded as recording a compressional event, is re-evaluated, based on field studies in the Marguareis massif, Maritime–Ligurian Alps. In this external, weakly metamorphic Briançonnais unit, we describe N-trending, folded paleo-normal faults. These paleofaults operated during the Late Cretaceous–Late Eocene, and control both the thickness of the Senonian–Paleocene calcschists and the distribution of the disconformable Middle Eocene–Early Priabonian formations, i.e. the channelised, resedimented Nummulitic limestones, associated with sandy turbidites, and the sandy-calcareous Lower Flysch Noir. The chaotic Upper Flysch Noir (Priabonian), which includes olistoliths from the Helminthoid Flysch nappes, disconformably overlies the Late Cretaceous–Middle/Late Eocene levels. At the scale of the whole Briançonnais domain of the French–Italian Alps, the superimposed Senonian–Eocene disconformities would indicate extensional faulting and block tilting, associated with a regional uplift which caused emersion of part of the domain (most internal Briançonnais, Corsica). Extension and coeval uplift would record the crossing of the frontal flexure (external bulge) of the European/Briançonnais lower plate situated west of the Alpine subduction zone between 80–70 Ma and ∼40 Ma, i.e. before the subduction of the Briançonnais plateau around 38–35 Ma.

Post-World War II uranium changes in dated Mont Blanc ice and snow.

Recent controversies concerning the possibility of environmental contamination due to the use of uranium in classical weaponry have led us to realize that there is a lack of time series for this metal from environmental archives. We have therefore performed analysis of a dated 140 m-long ice/snow core that was drilled in 1994 at a cold high altitude site (4250 m) near the summit of Mont Blanc in the French-Italian Alps. Ultraclean analytical procedures were employed in our analyses. Uranium concentrations were determined by inductively coupled plasma sector field mass spectrometry. In ice dating from before the 1940s, uranium concentrations are found to have remained fairly constant and can be explained simply by a crustal contribution. For the post-World War II layers, on the other hand, the data show large excesses above crustal contributions. These uranium excesses are attributed to tropospheric transport of dust emitted during extensive mining and milling operations which took place in the GDR and to a smaller extent in France at that time. There is no enhancement in uranium concentrations in the ice layer in which fallout from the 1986 Chernobyl accident was previously identified from a gross beta activity vs depth profile.

An excursion in the French–Italian Alps: the ‘Atlantic’‐type ophiolite at Mont Chenaillet

In his famous address to the Geological Society of America in 1957, H. H. Read concluded that ‘there are granites and granites’. This is equally true for ophiolites, slices of oceanic lithosphere produced by sea‐floor spreading and preserved by obduction during plate collision. Although they form in similar ways, it is clear that there are different types of ophiolite which originate under different conditions. Compared to the ‘classic’ ophiolites of Oman, many, such as those in the Alps, lack a sheeted dyke complex and were for a long time considered abnormal. Analogues for this type have now been found forming today and they occur when the rate of spreading is slow.

SIGNIFICANCE OF SANDSTONES INTERBEDDED IN THE JURASSIC BASALTS OF THE BALAGNE OPHIOLITIC NAPPE (CORSICA, FRANCE)

The Balagne Nappe which includes a thick ophiolitic succession, has an isolated external western position and is underlain by Eocene rocks over the autochthonous Corsican basement. The nappe consists, from base to top, of: 1) basaltic pillow lavas up to 1 km thick, 2) oceanic sediments (radiolarites, limestones showing diverse facies, particularly pelagic, pelites with interbeds of “Palombini”-type limestones, and 3) detrital formations ranging from the Albian- Cenomanian to Middle Eocene. The trace element content of the basalts of the Balagne Nappe s.l. is characteristic of enriched mid-oceanic ridge basalts (EMORB). In contrast, lavas of the more eastern Ligurian Units, such as the Inzecca Unit (Upper ‘Schistes lustres’), have an N-MORB character. We can thus define a marginal “Balagne-Ligurian domain”. In their lower part close to the gabbroic substratum, near Piana di Castifao, the Jurassic basalts have a level of feldspathic and micaceous quartzitic sandstone with calcareous cement (Baud, 1975). This level, 3 m thick, is intercalated within two 8-m layers of basaltic breccia (exploded pillows), sandwiched between flows of pillow lavas in places showing normal polarity. This rules out a tectonic hypothesis for the contacts at the base and top of the sandstones, as both contacts are clearly stratigraphic. The top of the sandstones is coarse grained, with lithic debris of continental origin and basalt fragments. The heavy minerals originate either from the oceanic or continental material. Zircons are particularly abundant and well preserved, which indicates limited transport. The typological study, according to Pupin’s diagram (1980), reveals that zircons plot in the field overlapping that of zircons from calc-alkaline granites (s.l.), highly abundant in the Corsican-Sardinian batholith. The Piana di Castifao sandstone interbed is the only known example in the Corsican Ligurian ophiolites. A similar thin bed has been described from the top of the ophiolitic sequence of the “Lago Nero-Replatte Nappe” to the east of Briancon in the French-Italian Alps. Similarly, in the Queyras region West of Mount Viso were reported sands and gravels with granite clasts, here there are underlying pillow basalts extruded over a serpentinite substratum. In both cases (east of Briancon and Queyras), no geological nor geochemical indications were found to constrain the position of the continent that supplied the detrital material. The detrital material originated from a continental source similar to that of Piana di Castifao. The Balagne-Ligurian domain of the Ligurian Ocean must therefore have been situated, during the Jurassic, relatively close to the Western European continental margin, as indicated by the geochemical facies of the EMORB, the basement fragments within the San Colombano supra-ophiolitic limestones, and the Piana di Castifao quartzitic interbed. The eastern margin of the Ligurian Ocean was also characterized by continental detritus as shown in the Cretaceous External Ligurides in the Northern Apennines.

Relief distribution, morphology and cenozoic differential uplift in the Argentera Massif (French-Italian Alps)

Relief distribution, morphology and cenozoic differential uplift in the Argentera Massif (French-Italian Alps)

A two hundred years record of atmospheric cadmium, copper and zinc concentrations in high altitude snow and ice from the French‐Italian Alps

Cd, Cu and Zn have been measured using ultraclean procedures in snow and ice deposited at a high altitude location in the French/Italian Alps during the past two centuries. These data provide the first time series of changes in the occurrence of heavy metals in ice and snow from temperate regions since the Industrial Revolution. Concentrations are constant until the end of the nineteenth century. Then they increase by 10, 15 and 30 fold for Cu, Cd and Zn, respectively till the 1970s. During the following two decades Cd and Zn concentrations then decrease whilst Cu continues to increase. These temporal changes are compared with changes in emissions in Western Europe.