In the Western Alps a steeply dipping km-scale shear zone (the Ferriere-Mollières shear zone) cross-cuts Variscan migmatites in the Argentera-Mercantour External Crystalline Massif.Structural analysis joined with kinematic vorticity and finite strain analyses allowed to recognize a high-temperature deformation associated to dextral transpression characterized by a variation in the percentage of pure shear and simple shear along a deformation gradient. U-Th-Pb dating of syn-kinematic monazites was performed on mylonites. The oldest ~340 Ma ages were obtained in protomylonites whereas ages of ~ 320 Ma were found in mylonites from the core of the shear zone. These ages indicate that the Ferriere-Mollières shear zone is a still preserved Variscan shear zone.Ages of ~320 Ma obtained in this work are in agreement with ages of the dextral transpressional shear zones occurring in the Maures-Tanneron Massif and Corsica-Sardinia. However, transpression in the Argentera-Mercantour Massif started earlier than in other sectors of the southern Variscan Belt. This is possibly caused by the curvature of the belt triggering the progressive migration of shear deformation. Our data allow a correlation between the Argentera-Mercantour Massif and other segments of the Southern European Variscan Belt, in particular with Maures-Tanneron Massif and Corsica-Sardinia and contribute to fill a gap in the age of activity and in the kinematics of the flow of the system of dextral shear zones of the southern portion of the EVSZ.
The Ferriere-Mollieres Shear Zone (FMSZ) is a regional shear zone cross-cutting the Argentera External Crystalline Massif (Western Alps). It shows a NW-SE striking dextral shear zone separating two Variscan migmatitic complexes: the Tinèe to the SW and the Gesso-Stura-Vesubiè to the NE. Geological-structural mapping at 1:10,000 scale focused on the characterization of mylonitic deformation. A deformation gradient has been observed towards the core of the shear zone marked by the occurrence of ultramylonites and rare phyllonitic layers. Protomylonites passing to unsheared migmatites occur in the outer zones. Low-angle shear zones with a top-to-the S and SW sense of shear cross-cut the previous mylonitic foliation. The FMSZ is a Variscan transpressive shear zone activated during the Late Carboniferous under amphibolite-facies metamorphic condition. The shear zone has been partially reactivated under greenschist-facies metamorphic conditions during Alpine Orogenesis.
Nowadays, the balance between incoming precipitation and stream or spring discharge is a challenging aspect in many scientific disciplines related to water management. In this regard, although advances in the methodologies for water balance calculation concerning each component of the water cycle have been achieved, the Thornthwaite–Mather method remains one of the most used, especially for hydrogeological purposes. In fact, in contrast to physical-based models, which require many input parameters, the Thornthwaite–Mather method is a simple, empirical, data-driven procedure in which the error associated with its use is smaller than that associated with the measurement of input data. The disadvantage of this method is that elaboration times can be excessively long if a classical MS Excel file is used for a large amount of data. Although many authors have attempted to automatize the procedure using simple algorithms or graphical user interfaces, some bugs have been detected. For these reasons, we propose a WebApp for monthly water balance calculation, called WaterbalANce. WaterbalANce was written in Python and is driven by a serverless computing approach. Two respective European watersheds are selected and presented to demonstrate the application of this method.
Carbonate aquifers are characterised by strong heterogeneities and their modelling is often a challenging aspect in hydrological studies. Understanding carbonate aquifers can be more complicated in the case of strong seismic events which have been widely demonstrated to influence groundwater flow over wide areas or on a local scale. The 2016–2017 seismic sequence of Central Italy is a paradigmatic example of how earthquakes play an important role in groundwater and surface water modifications. The Campiano catchment, which experienced significant discharge modifications immediately after the mainshocks of the 2016–2017 seismic sequence (Mmax = 6.5) has been analysed in this study. The study area is within an Italian national park (Sibillini Mts.) and thus has importance from a naturalistic and socio-economic standpoint. The research strategy coupled long-period artificial tracer tests (conducted both before and after the main earthquakes), geochemical and discharge analyses and isotope hydrology with hydrogeological cross-sections. This study highlights how the seismic sequence temporarily changed the behaviour of the normal faults which act predominantly as barriers to flow in the inter-seismic period, with water flow being normally favoured along the fault strikes. On the contrary, during earthquakes, groundwater flow can be significantly diverted perpendicularly to fault-strikes due to co-seismic fracturing and a consequent permeability increase. The interaction between groundwater and surface water is not only important from the point of view of scientific research but also has significant implications at an economic and social level.
This study wants to give a contribution to the semi-automatic evaluation of rock mass discontinuities, orientation and spacing, as important parameters used in Engineering. In complex and inaccessible study areas, a traditional geological survey is hard to conduct, therefore, remote sensing techniques have proven to be a very useful tool for discontinuity analysis. However, critical expert judgment is necessary to make reliable analyses. For this reason, the open-source Python tool named DCS (Discontinuities Classification and Spacing) was developed to manage point cloud data. The tool is written in Python and is based on semi-supervised clustering. By this approach the users can: (a) estimate the number of discontinuity sets (here referred to as “clusters”) using the Error Sum of Squares (SSE) method and the K-means algorithm; (b) evaluate step by step the quality of the classification visualizing the stereonet and the scatterplot of dip vs. dip direction from the clustering; (c) supervise the clustering procedure through a manual initialization of centroids; (d) calculate the normal spacing. In contrast to other algorithms available in the literature, the DCS method does not require complex parameters as inputs for the classification and permits the users to supervise the procedure at each step. The DCS approach was tested on the steep coastal cliff of Ancona town (Italy), called the Cardeto–Passetto cliff, which is characterized by a complex fracturing and is largely affected by rockfall phenomena. The results of discontinuity orientation were validated with the field survey and compared with the ones of the FACETS plug-in of CloudCompare. In addition, the algorithm was tested and validated on regular surfaces of an anthropic wall located at the bottom of the cliff. Eventually, a kinematic analysis of rock slope stability was performed, discussing the advantages and limitations of the methods considered and making fundamental considerations on their use.
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