Faulting of a turbidite sandstone-siltstone successions: the case study of the Macigno Formation, Tuscany, Italy

Faults in siliciclastic rocks are characterized by a great variability of fault zone architecture and relative permeability properties. This is because siliciclastic rocks (i.e turbidites) are often represented by alternating beds of various thickness and grain size forming a succession of strata with contrasting mechanical properties. For example, the presence of sandstone and clay-rich layers is responsible for the simultaneous occurrence of brittle and ductile deformation, known as “clay smear structures”. Moreover, numerous studies have identified grain size as one of the main influencing factors for fault nucleation processes and fracture intensity in the damage zone. In this work, we present the results of field and laboratory analyses performed on the Macigno Formation cropping out along the coast of western Tuscany. Here, the Macigno Formation is represented by Late Oligocene foredeep siliciclastic succession dominated by turbiditic sandstones with minor siltstones, mudstones, marls and shales. Thin section and 3D analyses, performed by X-ray Synchrotron tomography, allowed us to characterize the grain size and grain and cement composition of studied rocks. Grain size varies from channelized fine-grained sandstones to granule-conglomerates beds (0.006 mm to 4 mm) alternating with heterolithic levee strata of siltstones to fine-grained sandstones (0.0035-0.008 mm). The lithic components consist of metamorphic rocks by 70-80%, magmatic rocks by 15-20% and sedimentary rocks by 5-15%. The turbidite beds are normally well-cemented (by quartz and calcite) and heavily faulted and fractured. Investigated faults show dip-, oblique- and and strike-slip motion and their displacement range from 10s of centimetres to 10s of metres. We documented how both the grain size and the mechanical properties of the alternating beds strongly control the fault zone architecture, in particular in terms of damage zone thickness and fracture frequency. The fault rock types (i.e. breccia vs. gauge) are strictly related to the amount of displacement as well as to the grain size and the cementation of the sandstone. Furthermore, the development of clay smear structures are enhanced by the presence of interbedded thin clay-rich layers

Guest or pest? Spatio-temporal occurrence and effects on soil and vegetation of the wild boar on the Elba island

In areas where allochthonous large mammals, such as the wild boars (Sus scrofa), occur in high density, human-wildlife conflicts may arise. In these contexts, assessing spatio-temporal patterns of the introduced population is paramount to its management. Here, we studied wild boars in the Elba island, Italy, where they have been introduced and are perceived as pests. While crop-raiding has been documented, no studies addressed the spatio-temporal occurrence, nor the impact of foraging on natural habitat. We surveyed the Western part of the island with three camera trapping surveys within one year. We found that the species' estimated occupancy probability was higher in summer-autumn (0.75±0.14) and winter-early spring (0.70±0.10) than in late spring-summer (0.53±0.15), whereas detection probability did not vary. Occupancy was significantly associated with elevation and vegetation cover, with preference for lower elevation and woodland. The lower site use of wild boars during spring-summer might reflect lower food availability in this season, and/or movements towards landfarms outside the sampled area. Detectability increased with proximity to roads during spring-summer and decreased with humans' relative abundance in the other periods. Moreover, boars were mainly nocturnal, with an overlap with human activity that decreased when human presence was higher. Combined, these suggest behavioural avoidance of human disturbance by boars. We also evaluated the impact of boars' foraging on the soil and vegetation and found that it was higher in pine plantations than other covers, however, it was not associated with variation in boars' occupancy across habitats. Our results indicate that the spatio-temporal activity of wild boars on Elba island appears driven by seasonal preferences for food-rich cover and avoidance of human disturbance. The lowered site use in months with lower resources could partially reflect increased proximity to settled and farmed areas, which may, in turn, trigger crop-raiding and hence the negative perception by residents

Biodegradation of porous calcium phosphate scaffolds in an ectopic bone formation model studied by X-ray computed microtomograph

Three types of ceramic scaffolds with different composition and structure [namely synthetic 100% hydroxyapatite (HA; Engipore), synthetic calcium phosphate multiphase biomaterial containing 67% silicon stabilized tricalcium phosphate (Si-TCP; Skelite™) and natural bone mineral derived scaffolds (Bio-oss®)] were seeded with mesenchymal stem cells (MSC) and ectopically implanted for 8 and 16 weeks in immunodeficient mice. X-ray synchrotron radiation microtomography was used to derive 3D structural information on the same scaffolds both before and after implantation. Meaningful images and morphometric parameters such as scaffold and bone volume fraction, mean thickness and thickness distribution of the different phases as a function of the implantation time, were obtained. The used imaging algorithms allowed a direct comparison and registration of the 3D structure before and after implantation of the same sub-volume of a given scaffold. In this way it was possible to directly monitor the tissue engineered bone growth and the complete or partial degradation of the scaffold.Further, the detailed kinetics studies on Skelite™ scaffolds implanted for different length of times from 3 days to 24 weeks, revealed in the X-ray absorption histograms two separate peaks associated to HA and TCP. It was therefore possible to observe that the progressive degradation of the Skelite™ scaffolds was mainly due to the resorption of TCP. The different saturation times in the tissue engineered bone growth and in the TCP resorption confirmed that the bone growth was not limited the scaffold regions that were resorbed but continued in the inward direction with respect to the pore surface