Silvio Di Nocera

Stratigraphy and Detrital Modes of Upper Messinian Post-evaporitic Sandstones of the Southern Apennines, Italy: Evidence of Foreland-Basin Evolution during the Messinian Mediterranean Salinity Crisis

During the Messinian, the southern Apennines thrust belt experienced a period of strong tectonic rearrangement and accretion, activation of overthrusts, and consequent migration of depocenters. The upper Miocene successions cropping out in the northern segment of the southern Apennine thrust belt have good potential for improving our understanding of the interplay between Messinian salinity-crisis events and foreland-basin evolution. The local Messinian stratigraphy includes: (1) pre-evaporitic thin-bedded euxinic marly clay, interbedded with diatomaceous marls; (2) evaporitic limestone, crystalline gypsum, and reworked gypsum; (3) post-evaporitic deposits subdivided into two main units: the Torrente Fiumarella unit and the Anzano Molasse Formation that grade upward into ostracod-rich deposits (Lago-Mare facies). The evaporitic and post-evaporitic sequences are separated by an angular unconformity. This paper deals with the stratigraphic and petrographic study of the post-evaporitic deposits. The Torrente Fiumarella unit includes lacustrine and alluvial conglomerates, quartzolithic sandstones containing abundant carbonate detritus, shale, and reworked clastic gypsum. The Anzano Molasse Formation includes thick-bedded deltaic to turbiditic conglomerates and sandstones passing upward to thin-bedded turbidite sandstones and marlyclayey siltstones. Sandstones are quartzofeldspathic with variable proportions of sedimentary (both carbonate and siliciclastic) and plutonic detritus. In particular, two populations are present, plutonic-rich and mixed plutonic-sedimentary. Volcaniclastic layers, composed of dominantly vitric particles (shards and pumice), are also interbedded within Anzano Molasse sandstones. The Anzano succession includes rare freshwater ostracods that increase in abundance in the uppermost Lago-Mare facies. The Lago-Mare facies deposits are represented by silty-marly clay with abundant Ostracoda shells (Ilyocypris gibba, Cyprideis torosa and Candona sp.) and intrarenite having abundant intrabasinal carbonate particles (ooids, peloids, and bioclasts) and subordinate extrabasinal noncarbonate and carbonate particles. The post-evaporitic sequences represent an infilled foredeep basin, with a lacustrine environment progressively deepening and experiencing gravity resedimentation. Detrital modes document complex provenance relations from upper Messinian accreted terranes of the southern Apennines thrust belt. Post-evaporitic sandstones in the Irpinia-Daunia sector of the southern Apennines foreland-basin system record both the effects of the foreland tectonic evolution and the Messinian Mediterranean salinity crisis. They may represent alternative models for foreland-basin evolution during a restricted time in late Messinian, which can be applicable also in other portions of the circum-Mediterranean orogen.

Soil depth reconstruction for the assessment of the susceptibility to shallow landslides in fine-grained slopes

This paper proposes a methodology aimed at reconstructing the maximum thickness mobilized by shallow landslides in fine-grained soils with the aid of geological and geotechnical analyses. The methodology, implemented within a geographic information system (GIS) environment, is composed of two stages for map reconstruction and two stages for map validation. The first stage of map reconstruction is aimed at individuating the soil thickness on the basis of only topographical and geological analyses; the second stage improves the previously obtained map with the aid of morphological and geotechnical analyses that provide a thickness map usable for shallow landslide susceptibility assessment. This map is validated with the aid of both in situ investigations (stage I), and geotechnical models able to back-analyse shallow precipitation-induced landslides over a wide area (stage II). An application of the proposed methodology is provided for a test area of the Calabria region (southern Italy) that is representative of the Catanzaro Strait, where widely diffused shallow landslides in fine-grained soils systematically occur. The results highlight the usefulness and reliability of the geotechnical models when implemented with the aid of a database representative of fine-grained soils while a secondary role is played by in situ investigations that in the test site have been performed only in a few representative and accessible areas.

Geology, slow-moving landslides, and damages to buildings in the Verbicaro area (north-western Calabria region, southern Italy)

ABSTRACT This paper presents a mass movement inventory map at 1:5000 scale of the Verbicaro area (about 13 km2) located in the Calabria region (southern Italy). The Main Map results from the visual interpretation of aerial photographs, multi-temporal geomorphological field surveys, and field investigations of damage suffered by buildings. Some 53% of the study area is affected by a total of 252 landslides, comprising different types, state of activity, and size. The mapped landslides, mainly complex type, involve low-grade metamorphic rocks; among these, 15% are active and slow-move on pre-existing sliding surfaces. Moreover, out of 492 surveyed buildings, 347 are located on landslide-affected areas and experienced damages covering a broad range of severity levels. The Main Map can represent a useful tool for authorities in charge of land-use planning and urban management and can be used to pursue landslide risk analyses.

Hyperconcentrated Flow Susceptibility Analysis and Zoning at Medium Scale: Methodological Approach and Case Study

A methodological approach for the susceptibility analysis and zoning, at medium scale, of hyperconcentrated flows is presented. The adopted procedure comprises the following steps: (1) collection of data useful to acquire detailed knowledge of the slope processes leading to flow-like mass movements in the site; (2) hyperconcentrated flow susceptibility analyses via heuristic and statistic procedures; (3) hyperconcentrated flow susceptibility zoning (1:25,000 scale) at a preliminary/intermediate level. The procedure is applied to the test site of Monte Albino, (southern Italy), which extends over an area of around 400 ha. The obtained results emphasize the potential of an approach which moves from preliminary to intermediate level of susceptibility zoning. The results also highlight the important role played by the combined use of different procedures, based on heuristic and statistical models, in defining a standardised criterion to be adopted in problems dealing with the analysis and zoning of susceptibility to hyperconcentrated flows.