2,248 research outputs found
Foredeep turbidites of the Miocene Marnoso-arenacea Formation (Northern Apennines)
No full textThe Marnoso-arenacea Formation (MAF, Langhian-Tortonian) was deposited in an elongate, NW-stretched
foredeep basin formed in front of the growing Northern Apennines orogenic wedge (Figs. 2, 3A). These types
of deposits have always had a fundamental role in the hystory of turbidites, because a great part of the models
and facies schemes proposed in the literature have often been developed on these types of deposits. Among
foredeep turbidites, the MAF is probably the most famous, the best exposed and less structurally deformed,
due to its relatively external position within the Apenninic orogen. These characteristics have often favoured
detailed physical stratigraphy studies, such as the pioneering ones by Ricci Lucchi and his co-workers (see for
example Ricci Lucchi & Valmori, 1980).
As indicated in figure 3, an idealized transect oriented perpendicularly to the main structural axes shows that
sedimentation of a foreland region takes place in three distinct and coeval basins including: a) wedge-top
basins, characterized by alluvial, deltaic and mixed depositional systems; b) a foredeep basin,
characteristically in-filled with deep-water basinal turbidites; c) an outer and shallower ramp developed on
the passive foreland plate. The progressive thrust propagation toward the outer margin of the basin produces
a vertical superimposition of three depositional systems that, from base to top, are: (1) highly efficient
basinal turbidite systems and associated hemipelagic deposits; (2) mixed depositional systems, in which
turbidite-like bodies are deposited by poorly efficient gravity flows in a structurally confined basin. They can
be associated to prodeltaic sediments, both vertically and laterally; (3) flood-dominated deltaic systems (see
Mutti et al., 2003).
The vertical stacking pattern of the MAF, illustrated in figures 4 and 33, is characterized by same vertical
stratigraphic evolution in which at least three main depositional systems can be recognized and are represented
by Langhian to Serravallian high-efficiency basinal turbidites, Tortonian low-efficiency mixed turbidites and
shallow water Messinian euxinic shales and evaporites (Ricci Lucchi, 1978, 1981, 1986; Mutti et al., 2002a;
Roveri et al., 2003; Tinterri & Muzzi Magalhaes, 2011). The MAF, therefore, consists of a shoaling-up
stratigraphic succession, which results from the progressive closure of the foredeep due to the north-eastward
propagation of the main thrust front of the MAF. Consequently, this eastward thrust propagation has produced
a progressive uplift of the inner portions of the foredeep and a subsequent shifting in the same direction of themain depocentres. For this reason, Ricci Lucchi (1986) introduced the concepts of inner stage or basin
(Langhian-Serravallian in age) and outer stage or basin (Tortonian in age). The first one is characterized by deep
water high efficiency basinal turbidites, while the second one consists of low-efficient mixed turbidites in a
shallower and more confined basin. The passage between inner and outer stages is recorded by an important
tectonic phase (upper Serravallian in age) characterising the basal part of Unit V by Muzzi Magalhaes & Tinterri
(2010), which is time equivalent to the Firenzuola and Paretaio systems (Figs. 4 and 33).
The MAF stratigraphic succession, therefore, can be described in three stages: 1) a Langhian-Serravallian
inner basin; 2) an Upper Serravallian phase that records the transition between inner and outer basins and
3) a Tortonian outer basin (see Fig. 33). These three stages or basins are characterized by three different
facies associations related to the progressive increase, over time, of the structural control and the associated
morphologic confinement. This fact, influencing especially the erosive degree and the deceleration rate of
the turbidity currents, induces the formation of different bed types. The MAF foredeep can be considered as
a complex foredeep (as meant by Ricci Lucchi, 1986) characterized by sin-sedimentary structural highs and
depocenters related to the main thrust fronts within the MAF foredeep, which significantly control the lateral
and vertical distribution of turbidite facies (see Muzzi Magalhaes & Tinterri, 2010; Tinterri & Muzzi
Magalhaes, 2011).
Therefore, after a short and general introduction to the geology and stratigraphy of the northern Apennines,
the main targets of this field trip will be the stratigraphy, facies and processes of foredeep turbidites of the
MAF outcropping in the north-eastern Apennines, focusing especially on two specific aspects of the MAF
sedimentation: 1) the synsedimentary structural control affecting the MAF turbidites deposited in an elongate,
NW-stretched complex foredeep basin formed in front of the growing Northern Apennines orogenic wedge and
2) the vertical facies changes of the MAF stratigraphic succession (more than 4000m thick) in relation to the
progressive closure, uplift and consequent fragmentation of the foredeep due to the north-eastward
propagation of the Apennine orogenic wedge (Fig. 33)
Progressing in cable-in-conduit for fusion magnets: From ITER to low cost, high performance DEMO
No full textThe performance of ITER toroidal field (TF) conductors still have a significant margin for improvement because the effective strain between -0.62% and -0.95% limits the strands' critical current between 15% and 45% of the maximum achievable. Prototype Nb3Sn cable-in-conduit conductors have been designed, manufactured and tested in the frame of the EUROfusion DEMO activities. In these conductors the effective strain has shown a clear improvement with respect to the ITER conductors, reaching values between -0.55% and -0.28%, resulting in a strand critical current which is two to three times higher than in ITER conductors. In terms of the amount of Nb3Sn strand required for the construction of the DEMO TF magnet system, such improvement may lead to a reduction of at least a factor of two with respect to a similar magnet built with ITER type conductors; a further saving of Nb3Sn is possible if graded conductors/windings are employed. In the best case the DEMO TF magnet could require fewer Nb3Sn strands than the ITER one, despite the larger size of DEMO. Moreover high performance conductors could be operated at higher fields than ITER TF conductors, enabling the construction of low cost, compact, high field tokamaks. © 2018 IOP Publishing Ltd
Two novel approaches to study arthropod anatomy by using dualbeam FIB/SEM. Corresponding author
No full textTransmission Electron Microscopy (TEM) has always been the conventional method to study arthropod ultrastructure, while the use of Scanning Electron Microscopy (SEM) was mainly devoted to the examination of the external cuticular structures by secondary electrons. The new generation field emission SEMs are capable to generate images at sub-cellular level, comparable to TEM images employing backscattered electrons. The potential of this kind of acquisition becomes very powerful in the dual beam FIB/SEM where the SEM column is combined with a Focused Ion Beam (FIB) column. FIB uses ions as a nano-scalpel to slice samples fixed and embedded in resin, replacing traditional ultramicrotomy. We here present two novel methods, which optimize the use of FIB/SEM for studying arthropod anatomy
Il mobbing e il sistema organizzativo: processi, struttura e cultura
No full textIl capitolo affronta il tema della rilevanza del contesto organizzativo nel rischio di insorgenza di fenomeni di mobbing in azienda. I principali fattori analizzati riguardano il grado di gerarchizzazione della struttura organizzativa e, di conseguenza, anche la lunghezza delle catene decisionali; l’identità, la cultura ed i valori organizzativi, il ruolo della comunicazione interna, la leadership ed il processo di performance management. In quanto scenario all’interno del quale si possono sviluppare situazioni a rischio, l’organizzazione, in base a diverse configurazioni degli elementi sopra indicati, può essere definita più o meno trasparente, nel senso che può essere strutturata in modo da rendere più o meno facile la prevenzione e l’individuazione degli episodi di mobbing
Le tecnologie di rete a supporto del marketing e dell’identità del territorio nei distretti industriali
No full textThe Miocene turbidite deposits of the Marnoso-arenacea Formation (northern Apennines, Italy)
No full textIn the northern Apennines, thick and laterally
extensive terrigenous turbidite successions were
deposited during the late Oligocene and Miocene, as
the fill of elongated, NW-stretched foredeeps formed
in front of the growing Apennine orogenic wedge.
These turbidites, which are the classic sandy flysch
formations (Macigno, Cervarola,Marnoso-arenacea)
upon which Migliorini (1943) elaborated his
fundamental concept of resedimentation, were
progressively incorporated into the frontal part of the
orogen during its propagation towards the NE (see
also Kuenen & Migliorini, 1950). Among these
turbidite units, the Marnoso-arenacea Formation
(Langhian to Tortonian in age) is the best exposed and
less structurally deformed due to its relatively external
position within the Apennine orogen.
Thanks to the early works by Ricci Lucchi (1969, 1975,
1978, 1981, 1986),Mutti & Ricci Lucchi (1972), Ricci
Lucchi & Pignone (1979) and Ricci Lucchi & Valmori
(1980), the Langhian to Tortonian Marnoso-arenacea
Formation (MAF) is probably the most famous among
the clastic units, which record the structural evolution
of the Apennine thrust belt. However, recent studies
have shown that the MAF’s stratigraphy and
depositional settings are more complex than
previously thought, due to the accompanying
structural deformation that exerted a control over
basin geometry, facies distribution patterns and
emplacement of mass-transport complexes (de Jager,
1979; Ricci Lucchi, 1986; Argnani & Ricci Lucchi,
2001; Mutti et al., 2002a, 2003; Roveri et al., 2002;
Lucente & Pini, 2002, 2003; Lucente, 2004; Bonini,
2006).As a result, the vertical stacking pattern of the
Marnoso-arenacea records a close interaction
between thrust propagation towards the NE and
deposition from turbidity currents flowing towards the
SE, i.e. parallel to the thrust fronts.
This view has prompted a re-examination of the
MAF’s stratigraphy and facies starting with the
Turbidite Workshop held in Parma in 2002 (Mutti et
al., 2002a). The main intent of this field trip is to
present the preliminary results of the continuation of
this study, illustrating the sedimentary characteristics
of the stratigraphic succession of MAF (about 4000m
thick) that records the progressive closure of the
foredeep due to the NE propagation of thrust fronts.
In particular, this guide will present a detailed
stratigraphic cross-section (with bed-by-bed
correlations) of the upper Langhian to Serravallian
stratigraphic succession of MAF outcropping in
Romagna Apennines (Muzzi Magalhaes, 2009; see also
Muzzi Magalhaes and Tinterri, 2009). This interval
covers a thickness of about 2,500m and a distance of
about 60km in a SE direction, i.e. parallel to the
paleocurrents. It has well-exposed outcrops with good
lateral continuity and numerous key beds - many of
which are mapped on the geological maps of the
Emilia-Romagna region (Cerrina Feroni et al., 2002;
Martelli et al., 1994).These characteristics have proved
fundamental for many MAF field studies attempting
high-resolution stratal correlations over significant
distances.The pioneering work in this sense was Ricci
Lucchi & Valmori (1980), which took into account a
stratigraphic interval of 200m around the Contessa
key bed, for a horizontal distance of 120km. More
recently, Amy et al. (2005), Amy and Talling (2006)
presented correlations of a high number of
stratigraphic logs covering an interval of about 25m
comprised between the Contessa and Colombina 1
key beds
A new meshless approach to map electromagnetic loads for FEM analysis on DEMO TF coil system
No full textDemonstration fusion reactors (DEMO) are being envisaged to be able to produce commercial electrical power. The design of the DEMO magnets and of the constituting conductors is a crucial issue in the overall engineering design of such a large fusion machine. In the frame of the EU roadmap of the so-called fast track approach, mechanical studies of preliminary DEMO toroidal field (TF) coil system conceptual designs are being enforced. The magnetic field load acting on the DEMO TF coil conductor has to be evaluated as input in the FEM model mesh, in order to evaluate the stresses on the mechanical structure. To gain flexibility, a novel approach based on the meshless method of radial basis functions (RBF) has been implemented. The present paper describes this original and flexible approach for the generation and mapping of magnetic load on DEMO TF coil system. © 2015 Elsevier B.V. All rights reserved
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