Gianfranco Fioraso

Geology of Piemonte region (NW Italy, Alps–Apennines interference zone)

ABSTRACT The geological map of Piemonte Region (Italy) is a graphic representation of the geology of the region, grounded on a large geodatabase, that can be also browsed as an interactive scalable map (GeoPiemonte Map) using a WebGIS application. The Map, produced at 1:250,000 scale, is the first original release of the ‘GeoPiemonte Map’ project. The geological data represented on the map derive from a thorough revision of available geological maps and literature, integrated with unpublished original data. The revision and harmonisation of existing and new data have been based on explicit criteria used for the classification of geologic units and their representation on the Map. These criteria firstly aimed at providing a lithostratigraphic, hierarchic subdivision of Piemonte geologic units and describing them using shared concepts and vocabularies, consistent with IUGS Descriptive Standards for the Geosciences.

Geological map of the Monviso massif (Western Alps)

The 1:25,000 scale geological map of the Monviso massif encompasses an area of 61 km2, where different tectonic units of the Monviso Meta-ophiolite Complex (i.e. the Basal Serpentinite Unit, the Lago Superiore Shear Zone, the Viso Mozzo Unit, the Forciolline Unit and the Vallanta Unit) and different Quaternary deposits (i.e. alluvial, gravitative, glacial and periglacial deposits) have been distinguished. The Monviso Meta-ophiolite Complex is an important remnant of the Mesozoic Tethyan lithosphere stacked in the Western Alps, and consists of various sequences of serpentinized peridotites, metagabbros, metabasalts and metasediments, that are deformed by syn- to late-metamorphic folds and displaced by syn- to post-metamorphic faults. The geological map presented here provides new detailed lithological, structural and morphological data regarding (i) the tectonostratigraphy of the central sector of the Monviso Meta-ophiolite Complex and (ii) the Quaternary glacial and post-glacial evolution of the Monviso massif.

Geological map of the upper Pellice Valley (Italian Western Alps)

Abstract Please click here to download the map associated with this article. The 1:25,000 scale geological map of the upper Pellice Valley (Italian Western Alps) encompasses an area of roughly 60 km2 where a composite stack of both oceanic and continental Alpine units crops out. The four units distinguished in the map correspond, from bottom to top, to the Dora Maira Unit, a slice of the Paleozoic European crust, the Giulian-Sea Bianca Unit, a succession of Triassic to Lower Jurassic carbonate metasediments, the Monviso Unit, an ophiolitic remnant of the Mesozoic Tethyan Ocean, and the Bucie-Seilliere Unit, a carbonate metasedimentary succession of Upper Jurassic to Upper Cretaceous age. Each unit is bounded by syn-metamorphic faults (i.e. tectonic contacts) and is displaced by a postmetamorphic fault network, then discontinuously covered by heterogeneous alluvial, gravitative, glacial and periglacial Quaternary deposits. The map gives new and updated information about the structural and geological setting of the Pellice Valley through a detailed representation of the main lithological, structural and morphological features.

Little Ice Age and contemporary glacier extent in the Western and South-Western Piedmont Alps (North-Western Italy)

Glaciers are widely recognized as the best terrestrial indicators of climate change. Nevertheless, changes that have occurred since the end of the Little Ice Age (LIA) are often poorly understood. In Italy, glacier front variations in the last 100 years have been well documented, thanks to the efforts of the Italian Glaciological Committee (Comitato Glaciologico Italiano, CGI), which coordinates annual surveys on all glaciers, since 1927, in order to measure their front positions. However, although front variations are the easiest measurements to take in the field, they only partially describe changes that occur on the entire glacial mass. Moreover, the last national glacier inventory dates back to 1957–1958, which was promoted by the CGI on the occasion of the International Geophysical Year. Authors of the present work herein provide an updated inventory of present-day (2006) glaciers in the Western and South-Western Piedmont Alps (situated in the provinces of Turin and Cuneo). Along with the present-day glacial outlines, the map also includes a reconstruction of the extent of the glaciers during the Little Ice Age, inferred from morphological features such as LIA and post-LIA moraine ridges as well as the aid of historical archive data. Some basic glacier morphometric parameters (surface, length, width, mean slope, highest and lowest altitude, exposure) were computed for the two specified time periods (LIA and 2006). This study was carried out under the framework of the project ‘GlaRiskAlp – Glacial Risks in Western Alps’, project n.° 56 under the 2007–2013 ALCoTra programs.

Climate variability and Alpine glaciers evolution in Northwestern Italy from the Little Ice Age to the 2010s

In this work, we analyze climate variability and glacier evolution for a study area in the Northwestern Italian Alps from the Little Ice Age (LIA) to the 2010s. In this area, glacier retreat has been almost continuous since the end of the LIA, and many glaciers are now extinct. We compared glaciological and climatic data in order to evaluate the sensitivity of glaciers to temperature and precipitation trends. We found that temperatures show significant warming trends, while precipitation shows no clear signal. After the 1980s, the total number of positive trends in temperature increased, particularly minimum temperature. The latter does not seem to be the only cause of glacier shrinkage but rather on acceleration of an ongoing trend documented since the end of the LIA. In some rare cases, the effects of warming trends on glacier dynamics have been accentuated by a concomitant decrease in precipitation. We hope that this study will contribute to increase the knowledge of the relationships between climate variation and glacier evolution in the Greater Alpine Region.

Geology of the Villalvernia – Varzi Line Between Scrivia and Curone valleys (NW Italy)

The External Ligurian and Epiligurian Units in the Northern Apennines of Italy are tectonically juxtaposed with the Tertiary Piedmont Basin along the Villalvernia – Varzi Line, which represents a regional scale fault zone, E-striking. Our map, at the 1:20,000 scale, describes the tectono-stratigraphic evolution of this sector that resulted from multistage faulting along that fault zone. Four main tectonic stages are defined on the basis of the crosscutting relationships between mapped faults and stratigraphic unconformities: late Priabonian – Rupelian, Chattian – early Miocene, late Serravallian – Tortonian, and late Messinian – early Pliocene. Our results demonstrate that since the late Burdigalian, the Villalvernia – Varzi Line was sealed by the gravitational emplacement of a chaotic rock body. The deposition of the late Serravallian – early Messinian succession is controlled by NW-striking strike-slip faults that crosscut to the west the Villalvernia – Varzi Line. Extensional tectonics related to regional scale N-dipping tilting characterized the late Messinian – early Pliocene time interval.

The Classification Scheme of the Piemonte Geological Map and the OntoGeonous initiative

The OntoGeonous initiative has the goal of modeling a number of interconnected computational ontologies of geological concepts in order to exploit (i) the expressive power of ontological systems to merge several geological concepts (ii) the reasoning capabilities of the ontological systems to check the consistency of the currently existing knowledge stored in the Data Base of the Piemonte Geological Map at 1:250.000 scale and to infer novel knowledge.The prospect application of this initiative is the intelligent data collection and compilation of geological data base and the provision of sound semantic foundations for a modern cartographic project that provides a basis for a synthesis of geological data at the regional scale.

Sharing data and interpretations of geological maps via standardised metadata and geoportals

The so-called “Informatics-revolution” and related Information Technology (IT) are a chance to increase spreading of geoscientific knowledge and transfer of information represented in geological maps, but, in order to actually take advantage of systems-aided communication, geological information has to be specifically harmonized and standardized. New methodological and technological approaches in the representation and communication of geological maps are enabled by widespread use of Geographic Information Systems (GIS) and web mapping services (e.g. the WMS standard protocol) that i ) allow sharing and spatially discovering maps, and ii ) support interchange of data amongst different systems, experts and communities. Since sharing and retrieving of geological maps through geoportals and spatial data infrastructures spread, problems about semantic heterogeneity and different structures of geological databases (DB) come out. A strategy to meet needs of interoperability consists of integrating geological map DB by standard languages and meta-information, and is carried out by the INSPIRE (Infrastructure for Spatial Information in Europe) European directive that defines two relevant guidelines (the “Data Specification on Geology” and the “Metadata Implementing Rules”) usable to encode and share standardised geological information. An example of application of these standards is the Geoportal of the Torino Unit of the Institute for Geosciences and Earth Resources, where field data, map features and peculiar geological interpretations, extracted from GIS DB of geological maps, are given as single datasets and homogeneously described through specific metadata classes such as the Abstract sub-element and the Lineage sub-element. The two given examples of metadata compilations, referring to the Lis-Trana Fault and to the block stream deposits occurring in the “Torino Ovest” geological map (sheet n.155 of the Geological Map of Italy at 1:50,000 scale), highlight that standardisation is an opportunity i ) to better organize geological information, ii ) to give information about quality of data, and iii ) to specify intended meaning of interpreted features. Since metadata allow bringing out in an explicit format geological concepts and interpretations, reading of maps is improved and geoportals are actually a new method for encoding and sharing geological maps.

Geology of the Curone and Staffora Valleys (NW Italy): field constraints for the Late Cretaceous – Pliocene tectono-stratigraphic evolution of Northern Apennines

ABSTRACT In the northwestern part of Northern Apennines, between Curone and Staffora Valleys, the tectonic superposition between the External Ligurian Units (i.e. the ophiolitic-bearing chaotic complex of the Groppallo Unit and the non-ophiolitic Cassio Unit), the Middle Eocene – Miocene wedge-top basin Epiligurian Units succession, and the Late Messinian – Pliocene Po Plain succession, records the multistage tectono-stratigraphic evolution from subduction to continental collision. Our geological map, at the 1:20,000 scale, allows us to define 6 main tectonic stages on the basis of (i) the crosscutting relationships between main faults and local to regional stratigraphic unconformities and (ii) the differentiation among different types of chaotic rock unit (olistostromes and broken formations) deposited since Late Cretaceous to late Messinian. This approach provides a new understanding on the tectono-stratigraphic evolution of this sector, and its meaning in the evolution of the northwestern part of Northern Apennines.

Impact of massive deep-seated rock slope failures on mountain valley morphology in the northern Cottian Alps (NW Italy)

ABSTRACT Deep-seated rock slope failures represent effective mechanisms of natural rock mass-wasting, able to radically change mountain-valley morphology. In the northern Cottian Alps, an extraordinary concentration of instability phenomena occurs in extensive areas of the Susa and Chisone valleys. In the Main Map, at a scale of 1:30,000, a new representation of these deep-seated rock slope failures is proposed. Major effort has been invested in properly distinguishing between sackung-type deep-seated gravitational slope deformations and large landslides. Gravitational phenomena have affected the mountain landscape, with the development of impressive morphostructural features such as multiple-crested ridges and ridge top depressions. In the middle and distal portions of the slopes, sagging and toe bulging impose a marked change in the valley-slope profiles, in turn inducing secondary slope instabilities. Furthermore, mature deep-seated gravitational deformations and large landslides have, in some cases, made a significant impact on valley bottom morphology due to a partial or complete valley dam.