Search

Geological mapping, stratigraphic observations, and U/Pb dating allow reconstructing the pre-orogenic setting of the transition zone between the distal European passive margin and the Alpine Tethys in the southwestern Alps. Although convergent tectonics overprinted the syn-rift Jurassic tectonic features, our data document an articulated Jurassic physiography. From the distal European passive margin oceanward, we distinguished: the Dronero Unit (the southernmost Dora Maira massif), represents a continental margin composite basement wherein monometamorphic metasediments are interlayered with Late Permian (253.8 ± 2.7 Ma) metavolcanic rocks; the Sampeyre Unit, represents a structural high consisting of Lower Triassic Verrucano-facies siliciclastic metasediments unconformably sealed by Cretaceous calcschist bearing Globotruncana sp.; the Maira Unit, corresponds to a Middle Triassic platform succession detached from the Sampeyre Unit; the Grana Unit, corresponds to a Late Triassic–Late Jurassic platform to basin succession; the Queyras Schistes Lustrès Complex, represents the ocean basin succession. Tectonic slices of Cambrian (513.9 ± 2.7 Ma) metadiorite hosted in the Valmala Shear Zone, separating the Dronero Unit from the underlying (U)HP units of the Dora Maira massif, suggests a potential pre-Alpine activation of the shear zone. [ABSTRACT FROM AUTHOR]

The Jurassic ophiolites in the Northern Apennines and the Western Alps represent fossil mid-ocean ridge (MOR) oceanic lithosphere that formed in the Mesozoic Ligurian-Piedmont Ocean Basin (LPOB). Their sedimentary covers include chaotic rock units containing ophiolite-derived material. The processes of formation and the lithostratigraphic position of these chaotic units in the Western Alps remain a matter of debate, unlike their counterparts in the Northern Apennines. This is because of pervasive tectonic deformation and high-pressure metamorphism that affected their internal structure during collisional tectonics. A comparative analysis of these chaotic units in both mountain belts reveals the nature of processes involved in their formation. Chaotic deposits of gravitational origin occur both below and above the extrusive sequences in the ophiolites. They represent synextensional, hyperconcentrated deposits associated with the seafloor-spreading evolution of the LPOB lithosphere during Middle and Late Jurassic times. Mass transport deposits (MTDs) occur as intercalations within turbiditic sequences above the ophiolites. They represent syncontractional submarine slides that occurred on frontal accretionary prism slopes during the Late Cretaceous–Paleocene closure of the LPOB. The results of our comparative analysis imply that (1) the structure-stratigraphy of the chaotic deposits and MTDs of the Northern Apennines can be used as a proxy to better identify their metamorphosed and highly deformed counterparts in the Western Alps, (2) sedimentological processes associated with slow-spreading MOR tectonics and accretionary prism development in convergent-margin tectonics contributed to the sediment budgets of the cover sequences, and (3) magmatic, tectonic, and sedimentological processes that occurred during the formation of the Jurassic oceanic lithosphere and its sedimentary cover in the LPOB were remarkably uniform and synchronous. [ABSTRACT FROM AUTHOR]

The eclogite-facies Monviso meta-ophiolite Complex in the Western Alps represents a well-preserved fragment of oceanic lithosphere and related Upper Jurassic – Lower Cretaceous sedimentary covers. This meta-ophiolite sequence records the evolution of an oceanic core complex formed by mantle exhumation along an intra-oceanic detachment fault (the Baracun Shear Zone), related to the opening of the Ligurian–Piedmont oceanic basin (Alpine Tethys). On the basis of detailed geological mapping, and structural, stratigraphic and petrological observations, we propose a new interpretation for the tectonostratigraphic architecture of the Monviso meta-ophiolite Complex, and discuss the role played by structural inheritance in its formation. We document that subduction- and exhumation-related Alpine tectonics were strongly influenced by the inherited Jurassic intra-oceanic tectonosedimentary physiography. The latter, although strongly deformed during a major Alpine stage of non-cylindrical W-verging folding and faulting along exhumation-related Alpine shear zones (i.e. the Granero–Casteldelfino and Villanova–Armoine shear zones), was not completely dismembered into different tectonic units or subduction-related mélanges as suggested in previous interpretations. The present-day architecture of the Monviso meta-ophiolite Complex results from nappe-scale folding with a significant component of shearing, and strain partitioning of the Alpine deformation, which were controlled by the inherited occurrence of (i) lateral and vertical variations of facies and thickness of sediments, (ii) an intra-oceanic fault-rock assemblage, which acted as weak horizons in concentrating deformation, and (iii) remnants of a volcanic ridge, which consists of massive metabasalt. Thus, the recognition of pre-collisional, intra-oceanic, tectonostratigraphic inheritance represents an important step in reconstructing the tectonic evolution of meta-ophiolite units in orogenic belts. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM PUBLISHER]

The terms "bimrocks", "bimsoils" and "soil-rock mixtures" indicate different and very common types of geological units with a block-in-matrix fabric that are also "geotechnically complex formations" and are characterized by an internal heterogeneity, and spatial variability of mechanical parameters and lithological compositions. Due to this internal complexity, the understanding of their geomechanical behavior presents a key challenge in geotechnical engineering. However, the lack of a standardized and clear terminology complicates the discrimination of different types of complex formations and their internal mechanical properties, which leads to inconsistency in the literature and research studies. This inconsistency causes misunderstandings, with possible practical implications for the characterization, analysis, design and construction of engineering works. By a combination of geological and geotechnical observations, we propose a new classification for geotechnically complex formations, with particular attention to those with a block-in-matrix internal fabric. Four properties are at the base of this new classification and have a primary role in controlling the geotechnical behavior of block-in-matrix units (bimunits): (i) the composition (i.e., lithology, degree of lithification/consolidation, nature, and rheology) of blocks and the matrix that affects the water sensitivity, (ii) the degree of internal anisotropy (DA) of the block-in-matrix fabric, (iii) the degree of stratal disruption and mixing, and (iv) the volumetric block proportion (VPB). As a result, we classified bimunits in those with "anisotropic", "isotropic", and "mixed" (i.e., different behavior depending on the DA of the matrix) textures and, each of these types, into block-in-matrix rocks and block-in-matrix soils (bimrocks and bimsoils in the following). According to the water sensitivity of the matrix, bimrocks are also differentiated into "hard" and "soft". The novelty of the classification is that it is not limited to few types of geotechnically complex formations (e.g., flysch) but it can be easily applied to all field-based investigations of the different types of complex formations, regardless of their internal degree of stratal disruption, composition, and mechanical response to water sensitivity. [Display omitted] • Bimrocks and bimsoils are geotechnically complex formations. • Understanding their internal complexity is challenging for geotechnical engineers. • We propose a new practical classification of complex formations to aid comprehension. • Properties presented are composition, anisotropy/disruption degree, and block content. [ABSTRACT FROM AUTHOR]

In the Inner Western Alps, three different types of block-in-matrix structures (BIMs) formed sequentially through time at a convergent plate margin. These show the superposition of progressive deformation from (i) subduction to eclogite-facies depths, (ii) collision, accretion, and exhumation of oceanic crust, represented by the Monviso Meta-ophiolite Complex, to (iii) collision, accretion, and exhumation of the continental Dora Maira units. The Type 1 occurs in the metasedimentary cover of the Dora Maira Unit and consists of a map-scale broken formation with boudinaged ‘native’ blocks of marble (Early Jurassic) in a calcschist matrix. It results from the tectonic overprinting of exhumation-related folding (D2-stage) on an earlier subduction-related dismembered succession (D1-stage). Type 1 also includes ‘non-mappable’ BIMs with ‘exotic’ blocks, resulting from the gravitational collapse of the Triassic carbonate platform of European Continental Margin, triggered by the Early Jurassic rifting. In the Monviso Meta-ophiolite Complex, Types 2 and 3 represent tectonically induced broken and dismembered formations, respectively. They differ from each other in the degree of stratal disruption of primary interbedded horizons of mafic metabreccia (Type 3) and mafic metasandstone (Types 2 and 3) sourced by the Late Jurassic–Early Cretaceous denudation of an oceanic core complex. Dismembered interbeds (Type 2) and isolated blocks were mixed together (Type 3) by the overlap of D2 tectonics and late- to post-exhumation extensional shearing (D3-stage). Development of these types of BIMs may be common in many exhumed convergent plate margins, where severe tectonics and metamorphic recrystallization under high-pressure conditions normally prevent the reconstruction of BIMs or mélange-forming processes. Our findings show that documenting the mode and time of the processes forming BIMs is highly relevant in order to reconstruct the oceanic seafloor morphology and composition of associated stratigraphic successions, and their control in the evolution of those convergent plate margins. [ABSTRACT FROM AUTHOR]

In the Northern Apennines of Italy, mud-rich olistostromes (sedimentary mélanges) occur at different stratigraphic levels within the late Oligocene–early Miocene sedimentary record of episutural/wedge-top basins. They are widely distributed along the exhumed outer part of the Ligurian accretionary complex, atop the outer Apenninic prowedge, over an area about 300 km long and 10–15 km wide. Olistostromes represent excellent examples of ancient submarine mass-transport complexes (MTCs), consisting of stacked cohesive debris flows that can be directly compared to some of those observed in modern accretionary wedges. We describe the internal arrangement of olistostrome occurrences in the sector between Voghera and the Monferrato area, analysing their relationships with mesoscale liquefaction features, which are commonly difficult to observe in modern MTCs. Slope failures occurred in isolated sectors along the wedge front, where out-of-sequence thrusting, seismicity, and different pulses of overpressured tectonically induced fluid flows acted concomitantly. Referring to the Northern Apennines regional geology, we also point out a gradual lateral rejuvenation (from late Oligocene to early Miocene) toward the SE and an increasing size and thickness of the olistostromes along the strike of the frontal Apenninic prowedge. This suggests that morphological reshaping of the outer prowedge via mass-transport processes balanced, with different pulses over a short time span, the southeastward migration and segmentation of accretionary processes. The latter were probably favoured by the occurrence in the northwestern part of the Northern Apennines of major, inherited palaeogeographic features controlling the northward propagation of the prowedge. Detailed knowledge of olistostromes, as ancient examples of MTCs related to syn-sedimentary tectonics and shale diapirism, and of their lateral variations in term of age and size, provides useful information in regard to better understanding of both the tectono-stratigraphic evolution of the Apenninic prowedge and the submarine slope failures in modern accretionary wedges. [ABSTRACT FROM AUTHOR]

We investigated the recent evolution of the Po Plain-Alps system by integrating subsurface geophysical data from the Po Plain with new stratigraphic and structural observations from the Southern Alps margin. Inversion of structural data and chronology provided by stratigraphic constraints led to the definition of three tectonic events since the Pliocene, namely, the intra-Zanclean, the Gelasian, and the Middle Pleistocene, driven by an axis of maximum compression formerly oriented NE (intra-Zanclean) and then to the NNW (Gelasian and Middle Pleistocene). The associated deformation has been accommodated by two sets of faults consisting of NNE-trending thrust faults, mostly represented in the western sector of Lake Garda, and NW-trending strike-slip faults, observed in the southern and eastern sectors. The interplay between these two sets of faults is interpreted to produce short (<10 km length) thrust ramps activated in left transpression, bounded by longer (30-60 km) transfer faults activated in a right-lateral strike-slip motion. Based on this structural model, we infer moderate seismicity (Mw < 6) associated with the NNE-directed thrusts and stronger earthquakes (also Mw > 6.5) along the NW-trending strike-slip faults. In this framework, the newly defined Nogara fault and the Sant'Ambrogio fault, all pertaining to the NW-trending system, are regarded as potential candidates for the seismogenic source of the January A.D. 1117 event, the most destructive earthquake in the Po Plain. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM PUBLISHER]

The Apenninic fold-and-thrust belt in Italy represents one of several interconnected circum-Mediterranean orogens developed after the Late Cretaceous – early Cenozoic closure of Tethys and convergence between the European and African plates. The Geological Map of the Aventino River Valley, at 1:25,000 scale, provides original mapping of the outermost sector of Central Apennines in the Abruzzi region. Focusing on detailed mapping of the crosscutting relationships between the main regional thrust faults and tectonically driven stratigraphic unconformities, the map describes the complex structural and stratigraphic relationships between the Outer Abruzzi units (i.e. Porrara Unit), Apulia – Adriatic deformed units (i.e. Majella and Casoli Units), and the allochthonous Molise and Sicilide units. These tectono-stratigraphic relationships result from four main tectonic stages that occurred sequentially over a short time interval from late Messinian to early Pliocene. [ABSTRACT FROM AUTHOR]

We document in this study the internal structure of the Late Cretaceous-late Oligocene Ligurian accretionary wedge in northwestern Italy, and the occurrence in this exhumed wedge of broken formation and three different types of mélanges that formed sequentially through time. The broken formation is the oldest unit in the accretionary wedge and shows bedding-parallel boudinage structures, which developed as a result of layer-parallel extension at the toe of the internal part of the Alpine wedge front during the Late Cretaceous-middle Eocene. This broken formation experienced an overprint of tectonic, diapiric, and sedimentary processes as a result of continental collision in the late Oligocene. The NE-vergent thrusting and associated shortening produced a structurally ordered block-in-matrix fabric through mixing of both native and exotic blocks, forming the tectonic mélange. The concentration of overpressurized fluids along the thrust fault planes triggered the upward rise of shaly material, producing the diapiric mélange, which in turn provided the source material for the downslope emplacement of the youngest, late Oligocene sedimentary mélange. The sedimentary mélange units unconformably cover the collisional thrust faults, constraining the timing of both this episode of contractional deformation related to continental collision and the combination and overlap of tectonic, diapiric, and sedimentary processes. Our multiscale structural analysis of the Ligurian accretionary wedge shows that tectonic, diapiric, and sedimentary processes played a significant role in its evolution, and that the interplay between and the superposition of these different processes strongly controlled the dynamic equilibrium of the accretionary wedge in the NW Apennines-western Alps. This kind of polygenetic mélange development may be common in many modern and ancient accretionary complexes, and the processes involved in their formation are likely to be responsible for major tsunamic events in convergent margins. [ABSTRACT FROM AUTHOR]

The geological term "mélange" is used to indicate a vast group of "chaotic rock" units with a block-in-matrix internal arrangement exhumed in orogenic belts. Geotechnically such units are often defined as "complex formations", and are commonly associated with flysch-type formations. Such units range from coherent, bedding-concordant broken-formations to fully disrupted, discordant block-in-matrix rock assemblages. Mélanges derive from the progressive disruption and mixing of flysch-type successions from their earliest phases of development to their complete lithification and exhumation. They are the product of sedimentary (submarine mass transport), tectonic (thrust-related shearing) and mud-diapiric (fluid/gas driven remobilization of mud/shales) processes. Throughout a review of geological data, we show that the different intrinsic anatomical features and relationships with the host rocks shown by these various units allow differential internal anisotropy of the lithological properties, and, depending on their origin, size and distribution, they can variably influence the overall mechanical behavior of the host flysch-type formation. The review of geological data thus provides useful observations to distinguish different types of "complex formations" and block-in-matrix rocks with different geotechnical and mechanical characteristics, and then potentially suggesting the application of different rock or soil mechanics procedures. • Mélanges can be sedimentary, tectonic or diapiric in origin, or a combination thereof • These 3 types of mélanges are characterized by different internal architectures and relationships with the host flysch formation • Such characteristics deeply impact on their overall geotechnical behavior at different scales, for instance in controlling the orientation of the mechanically weak zones [ABSTRACT FROM AUTHOR]

The External Ligurian Units in western Monferrato (NW-Italy) have been always described as an undifferentiated chaotic complex. This map, at 1:10,000 scale, describes in detail the tectono-stratigraphic setting of these Units in the sector of the Alps–Apennines junction. Here, the External Ligurian Units represent the northwestern prolongation of the Northern Apennines and consist of a Late Cretaceous chaotic succession represented by theArgille varicoloriand the overlaying Monte Cassio Flysch. The late Eocene–Miocene episutural succession of the Tertiary Piedmont Basin rests unconformably on the External Ligurian Units. The mapped crosscutting relationships between stratigraphic unconformities and faults allow us to describe a complex tectono-stratigraphic setting that is the product of four tectonic stages. Layer-parallel extension related to Late Cretaceous–early Eocene deformation occurred in the internal sector of the Alpine accretionary wedge and is preserved within the External Ligurian Units which is sealed by the late Eocene deposits of the Tertiary Piedmont Basin. The unconformity at the base of the Oligocene succession records the drowning of shelf sediments controlled by NW-striking left-lateral transtensive faulting. A WNW-striking and NE-verging thrust superposes the External Ligurian Units onto the late Eocene–Oligocene deposits and it is sealed by the gravitational emplacement of late Oligocene Polygenetic argillaceous breccias. Both the WNW-striking thrust and the Polygenetic argillaceous breccias are cut by NW-striking right-lateral transpressive faults that are, in turn, sealed by the Tortonian unconformity. [ABSTRACT FROM AUTHOR]

Abstract: The Hamburg Klippe of the Central Appalachian orogenic belt exposed in eastern Pennsylvania displays a complex record of poly-phase mélange and broken formation development in a convergent margin setting. It includes an imbricate stack of tectonic slices, which consist of upper Cambrian to Upper Ordovician deep-water and continental slope sedimentary rocks, emplaced by gravity sliding onto the Laurentian passive margin during deposition of the Upper Ordovician Martinsburg Formation. Based on their internal structure and stratigraphy, the block-matrix ratios and relations, and the inferred tectonic settings of origin, we have differentiated the following mélanges and broken formations, whose evolutionary stages coincide with specific deformational phases in a complete orogenic cycle from subduction to collision: (i) sedimentary broken formations without exotic blocks, formed by in situ and local down-slope remobilization during the early stages of closure of the Octoraro Sea basin in the Early Ordovician; (ii) two types of sedimentary mélanges with exotic blocks, formed at the front of the advancing accretionary wedge during the Middle Ordovician subduction of the Laurentian continental margin beneath a microcontinent–magmatic arc tectonic assembly; (iii) layer-parallel, extensional broken formation and a diapiric mélange, formed in the outer trench and at the toe of the accretionary wedge, respectively, during the early–Late Ordovician; (iv) precursory olistostromes, formed during the Late Ordovician collisional episodes as the Hamburg Klippe was emplaced in the Martinsburg Formation on the downgoing Laurentian continental margin; and, (v) contractional deformation-related broken formations, formed at the base of main thrust faults overprinting the previously formed mélanges and broken formations. This sequential development of different mélange types in the Central Appalachians was strongly controlled by the degree of consolidation of the layered strata and their rheological differences, the structural level of mélange formation within the accretionary wedge, and the kinematics of deformational processes. [Copyright &y& Elsevier]

Abstract: The Argille varicolori (Varicolored scaly clays) of the External Ligurian Units of the Northern Apennines have been widely described as a typical unmetamorphosed broken formation (i.e., a chaotic unit without exotic blocks), produced by offscraping and tectonic imbrication during the evolution of the Ligurian accretionary wedge. Geological mapping and integrated structural and stratigraphic observations show that the Argille varicolori consist of diverse types of small-scale mélanges (non-mappable at a 1:25,000 scale) forming a composite chaotic unit, in which the superposition of tectonic, sedimentary and diapiric processes resulted in the occurrence of polygenetic chaotic bodies at different scales. These mélange units record the evolution of the Ligurian accretionary wedge from subduction to collision and intracontinental deformation. Tectonically Disrupted Body 1 (TDB1) comprises boudinage and pinch-and-swell structures formed by layer-parallel extension/contraction at the wedge front of the Ligurian accretionary complex during the late Cretaceous–middle Eocene. It is interleaved with non-mappable Gravity-driven Chaotic Bodies (GCB) developed during alternating episodes of accretion and removal of material at the wedge front. The late Oligocene–early Miocene out-of-sequence thrusting related to the collisional episodes in the Apennines overprinted the previously formed chaotic bodies and formed a polygenetic tectonic mélange (Tectonically Disrupted Body 2, TDB2). This unit is characterized by a structurally ordered block-in-matrix fabric and by the gradual decrease of stratal disruption away from the regional thrust. Overpressurized fluids concentrated along the shear surfaces, and the scaly cleavage planes facilitated the diapiric upward movement of unconsolidated sediments in the early Miocene. This process produced non-mappable shale dike injections (DDB1) and mappable Diapirically Disrupted Bodies (DDB2), which show an internal zonation of deformation. This deformation reworked the previously formed chaotic bodies. Although some of these polygenetic mélanges cannot be mapped at a 1:25,000 scale, their careful documentation provides a better understanding of time-progressive, scale-independent mélange-forming processes. [Copyright &y& Elsevier]

Melanges represent a significant component of collisional and accretionary orogenic belts and occur widely around the world. Since its first introduction and use, the term has evolved to cover both processes (tectonic, sedimentary, and diapiric) and tectonic settings of melange formation. The meaning and significance of various terms referring to the origin of 'block-in-matrix chaotic rocks' are still subject to debate. This study presents a historical overview of the evolving melange concept and investigates the relationships between melange types and their tectonic settings of formation. We investigate the contribution of mass-transport versus contractional deformation processes at the onset of melange formation and throughout the evolution of different melange types, and the nature of the continuum and transition from broken formations to true tectonic melanges. A melange is a mappable chaotic body of mixed rocks with a block-in-matrix fabric whose internal structure and evolution are intimately linked to the structural, sedimentary, magmatic, and metamorphic processes attending its origin. On the basis of a comparative analysis of exhumed, ancient on-land melanges and modern tectonic environments, where melange-forming processes are at work, such units are classified into those related to extensional tectonics, passive margin evolution, strike-slip tectonics, subduction zones, collisional tectonics, and intracontinental deformation. Sedimentation and contractional deformation contribute significantly to melange formation in all these tectonic environments, although the internal structure of deposits is strongly controlled and overprinted by processes that prevail during the last stages of melange formation in a single tectonic setting. Tectonic melanges are commonly subordinate to broken formations and are restricted to narrow, elongated-to-coalescent fault zones, large-scale fault zones, and plate boundaries. [ABSTRACT FROM AUTHOR]

In the peri-Adriatic region, melanges represent a significant component of the Apennine and Dinaride-Albanide-Hellenide orogenic belts as well as ancient and present-day accretionary wedges. Different melange types in this broad region provide an excellent case study to investigate the mode and nature of main processes (tectonic, sedimentary, and diapiric) involved in melange formation in contrasting geodynamic settings. We present a preliminary subdivision and classification of the peri-Adriatic melanges based on several years of field studies on chaotic rock bodies, including detailed structural and stratigraphic analyses. Six main categories of melanges are distinguished on the basis of the processes and geodynamic settings of their formation. These melange types are spatially and temporally associated with extensional tectonics, passive margin evolution, strike-slip tectonics, oceanic crust subduction, continental collision, and deformation. There appears to have been a strong interplay and some overlap between tectonic, sedimentary, and diapiric processes during melange formation; however, in highly deformed regions, it is still possible to distinguish those melanges that formed in different geodynamic environments and their main processes of formation. This study shows that a strong relationship exists between melange-forming processes and the palaeogeographic settings and conditions of melange formation. Given the differences in age, geographic location, and evolutionary patterns, we document the relative importance of melanges and broken formations in the tectonic evolution of the peri-Adriatic mountain belts. [ABSTRACT FROM AUTHOR]

Geologic mapping and integrated stratigraphic and structural observations of a gypsum quarry from northwestern Italy allow evaluation of the relative contributions, the time relationships, and the causative links between tectonic, sedimentary, and diapiric processes in the genesis of chaotic sediments of Messinian age. Three chaotic units are exposed in the quarry: together, they make up a composite chaotic unit that is unconformably overlain by post-chaotic sediments. Unit 1 is composed of blocks of primary evaporites that are juxtaposed to marine marls by subvertical transpressive faults and are parallel to the fault surfaces. Unit 2 unconformably overlies Unit 1, and consists of a lenticular sedimentary body containing both angular and rounded blocks, randomly distributed in a fine-grained matrix. Unit 3 consists of a 10-m-wide body bounded by transpressive faults, and pierces both Units 1 and 2. It is composed of strongly deformed muddy deposits that envelop blocks of gypsum and carbonate rocks. Between the core and the margins, various zones have been defined based on the increasing amount of deformation toward the margins. The post-chaotic sediments unconformably overlie both Units 1 and 2, sealing the main fault systems. The composite chaotic unit is related to thrust propagation during a regional phase of deformation, and is the result of different evolutionary stages, in each of which a single genetic mechanism prevailed. Tectonic faulting prevailed during stage 1 and was responsible for the formation of a tectonically disrupted assemblage (Unit 1). During stage 2, gravity-driven sedimentary phenomena, related to slope oversteepening triggered by ongoing thrust propagation, resulted in the deposition of Unit 2. Gravity sliding was favored by the mechanical weakening of sediments caused by tectonic faulting. Overpressure conditions resulting from the rapid deposition of Unit 2 triggered the rise of a diapir (Unit 3) that pierced Units 1 and 2. The involvement of methane-rich fluids in the formation of the diapir is suggested by the occurrence of blocks of methane-derived carbonates, found not in the quarry, but just outside it. [ABSTRACT FROM AUTHOR]

Paleogeographic reconstructions show that the Ligurian‐Piedmont Ocean (LPO) was a relatively narrow oceanic basin but the actual amount of oceanic lithosphere generated and the timing of magmatic accretion are still subjects of debate. New U–Pb dating of zircon from two pairs of FeTi‐oxide metagabbro and metaplagiogranite s.l. of the Susa and Lanzo Valleys Ophiolites (Western Alps) yields Late Jurassic magmatic ages (~150 Ma), 10–15 Ma younger than most of the magmatism in the LPO. The potential significance of the geochronological data presented are discussed in relation to the structural architecture of the LPO, emphasizing that the investigated ophiolites represent the youngest oceanic lithosphere accreted in the Western Alps. [ABSTRACT FROM AUTHOR]

The topmost Argille Azzurre (beds 1-2) and the basal Sabbie di Asti (beds 3-9) formations in the Villalvernia area are analysed in terms of palaeoecological and taxonomic features; the succession is 6 m thick and dates back to the middle Piacenzian within the Globorotalia bononiensis acme. The upper boundary of the clayey Bed 2 corresponds to an unconformity reflecting Pliocene tectonic activity. The study is focused on the fossil assemblages of beds 3, 4 and 9. The sandy Bed 3 yields 362 mollusc taxa; the assemblage is allochthonous and mixes infra- to circalittoral species accumulated by hyperpycnal mass-transport. The same mechanism is responsible for the origin of the overlying fossil unit (Bed 4) with numerous specimens of the Entobia-Gastrochaenolites ichnofacies. The autochthonous fossil assemblage of Bed 9 yields 308 molluscs, plus three brachiopods and ten fish taxa; most of them refer to the Posidonia meadow (HP), and their autochthony is shown by taphonomic features as skeletal integrity, mixing of successive generations or the limitation to juvenile ontogenetic stages of vagile and temporarily byssate species for which the HP performs a nursery function. Three brachiopods and 52 molluscs are here reported for the first time from the Pliocene of Piedmont. In the final chapter "Systematic Palaeontology" four brachiopods and 29 molluscs are described, among which there are eight new gastropod species: Crepidula bellardii n. sp., Conus dellabellai n. sp., Conus villalvernensis n. sp., Odetta chirlii n. sp., Ondina curta n. sp., Ondina elongata n. sp., Ondina pseudovitrea n. sp., Anisocycla subcylindrica n. sp. [ABSTRACT FROM AUTHOR]

The strong morphological similitude of the block-in-matrix fabric of chaotic rock units (mélanges and broken formations) makes problematic the recognition of their primary forming-processes. We present results of the comparison between magnetic fabric and mesoscale structural investigations of non-metamorphic tectonic, sedimentary, and polygenetic mélanges in the exhumed Late Cretaceous to early Eocene Ligurian accretionary complex and overlying wedge-top basin succession in the Northern Apennines (northwest Italy). Our findings show that the magnetic fabric reveals diagnostic configurations of principal anisotropy of magnetic susceptibility (AMS) axes orientation that are well comparable with the mesoscale block-in-matrix fabric of mélanges formed by different processes. Broken formations and tectonic mélanges show prolate and neutral-to-oblate ellipsoids, respectively, with magnetic fabric elements being consistent with those of the mesoscale anisotropic "structurally ordered" block-in-matrix fabric. Sedimentary mélanges show an oblate ellipsoid with a clear sedimentary magnetic fabric related to downslope gravitational emplacement. Polygenetic mélanges show the occurrence of a cumulative depositional and tectonic magnetic fabric. The comparison of field and laboratory investigations validate the analysis of magnetic features as a diagnostic tool suitable to analytically distinguish the contribution of different mélange forming-processes and their mutual superposition, and to better understand the geodynamic evolution of subduction-accretion complexes. [ABSTRACT FROM AUTHOR]

Background: Preschool children with clinically-diagnosed asthma have a higher rate of emergency department visits and consume more resources for management than older children. However, no clinical trials have yet been performed measuring the impact of a combined diagnostic, therapeutic and educational pathway regimen for evaluation of wheezing control in children aged less than 6 years. The purpose of the present study was to assess the impact of a pediatric program developed in Italy, the Diagnostic Therapeutic Educational Pathway (DTEP), for asthma management in children less than 6 years old attending an asthma referral center. Methods: This is a retrospective population-based cohort study performed in children with asthma aged 0–5 years, attending at "Io e l'Asma center", Brescia, Italy between September 2007 and December 2014. The incidence rates (IRs) of hospitalization, emergency room visits, use of outpatient services and drug usage for dyspnea, wheezing, or respiratory symptoms were evaluated for time periods prior to and after DTEP intervention. Results: A total of 741 patients, aged 0–5 years completed the DTEP, including 391 and 350 children aged 0–2 and 3–5 years, respectively. The percentage of children aged 0–2 and 3–5 years showing improved control of wheezing symptoms during the 1st to 3rd visit interval as a result of the DTEP intervention increased from 39.5 to 60.9% and from 25.5 to 75.5%, respectively. During these periods, the IRs showed a significant decrease for all outcomes, from-8.6% to − 80.4%. Although specific IRs for drug prescriptions declined, particularly for LABA plus corticosteroids, antibiotics, and systemic corticosteroids, they increased for SABA, inhaled corticosteroid and leukotriene receptor antagonist usage. Conclusions: The results suggest that a real-world assessment of the integrated DTEP program for preschool children provides evidence for improved wheezing control and reduction of adverse therapeutic related outcomes. [ABSTRACT FROM AUTHOR]

Depending on its chemical and mineralogical composition, the serpentinite represents a peculiar rocky material, which plays a significant role in influencing pedogenetic weathering, vegetation ecology, geo-mechanical and tectonic processes, as well as gravitational slope failure. In serpentinite-bearing environments the response to gravitational stress is more effective than in other rock types. In the Monviso meta-ophiolite Complex (Western Alps), a close relation between landsliding and serpentinite rock occurrences is particularly evident. Our geological map (), at a scale 1:10,000, illustrates the geology and geomorphological features of the Pui-Orgiera giant (2.98 km2) complex landslide, located on the southern slope of the Monviso Massif. This map clearly documents that the characteristics and kinematics of the landslide are closely associated to the anomalous thickening and widening increase of the Baracun Shear Zone, a remnants of an intra-oceanic detachment fault which separates serpentinite and meta-intrusives from metabasalt and metasediments of the Monviso meta-ophiolite Complex. [ABSTRACT FROM AUTHOR]

Abstract: Background: In spite of some evidence for positive effects of patient's education to asthma self‐management by randomized clinical trials, there are few studies on the impact of patient’ s educational programs in the real world. We aimed to assess the impact of a diagnostic therapeutic educational pathway (DTEP) on asthma control of children and adolescents by comparing frequency of outcomes indicative of asthma control before and after attending the pathway. Methods: This is a retrospective cohort study including all patients aged 6‐11 and 12‐17 years who attended the DTEP in 2007‐2014. The DTEP includes 3 specialist's evaluations at 8‐ to 12‐week intervals and two follow‐up visits. Patients and their parents receive an educational course concerning prevention measures, early recognition of symptoms, and appropriate use of drugs and devices. The rates of hospitalizations, outpatient services, emergency room visits, and drug prescriptions were considered as outcomes and computed as number of events divided by person‐time. Results: A total of 806 patients were enrolled. A statistically significant decrease in rates from before to after DTEP was observed for almost all outcomes, in both age groups, with relative risks ranging from 0.12 to 0.60. The rates of drug prescription showed a statistically significant decrease, from before to after DTEP, for each type of medicine for asthma, in both age groups, from percent difference of −66% to −24.3%. Conclusions: The positive impact of this program on the outcomes indicative of asthma control in both children and adolescents suggests that it may be valuable for asthma management. [ABSTRACT FROM AUTHOR]

Ophiolites of the Alpine belt derive from the closure of the Mesozoic Tethys Ocean that was interposed between the palaeo-Europe and palaeo-Adria continental plates. The Alpine orogeny has intensely reworked the oceanic rocks into metaophiolites with various metamorphic imprints. In the Western Alps, metaophiolites and continental-derived units are distributed within two paired bands: An inner band where Alpine subduction-related high-pressure (HP) metamorphism is preserved, and an outer band where blueschist to greenschist facies recrystallisation due to the decompression path prevails. The metaophiolites of the inner band are hugely important not just because they provide records of the prograde tectonic and metamorphic evolution of the Western Alps, but also because they retain the signature of the intra-oceanic tectono-sedimentary evolution. Lithostratigraphic and petrographic criteria applied to metasediments associated with HP metaophiolites reveal the occurrence of distinct tectono-stratigraphic successions including quartzites with marbles, chaotic rock units, and layered calc schists. These successions, although sliced, deformed, and superposed in complex ways during the orogenic stage, preserve remnants of their primary depositional setting constraining the pre-orogenic evolution of the Jurassic Tethys Ocean. [ABSTRACT FROM AUTHOR]

In the Valmala sector of the southern Dora Maira Massif (Western Alps), two different eclogite- and blueschist-facies units (i.e. the Rocca Solei and Dronero units, respectively), are separated by a shear zone (i.e. the Valmala Tectonic Unit), which peculiarly consists of mixed slices of ophiolitic and continental rocks. A detailed geological map at 1:10,000 scale allowed to point out that the tectonic slices within the Valmala Tectonic Unit consist of 'native' rock slices wrenched from the overlying Dronero Unit, and 'exotic' rocks likely sourced from other units of the Dora Maira and from a continental margin and an oceanic basin. On the contrary, rock slices sourced from the underlying Rocca Solei Unit are lacking. The overall tectonic stack results after an early subduction-related deformation phase (i.e. the D1), and the pervasive overprinting of two subsequent exhumation-related deformation phases (i.e. the D2 and D3). The Valmala Tectonic Unit is inferred to have played a role in decoupling the southern Dora Maira Massif during subduction, and/or in driving exhumation of the ultra-high pressure rocks occurring in the adjoining Brossasco-Isasca Unit. [ABSTRACT FROM AUTHOR]

The Sestola Vidiciatico tectonic Unit (SVU) accommodated the early Miocene convergence between the subducting Adriatic plate and the overriding Ligurian prism, and has been interpreted as a field analogue for the shallow portion of subduction megathrusts. The SVU incorporated sediments shortly after their deposition and was active down to burial depth corresponding to temperatures around 150 °C. Here, we describe the internal architecture of the basal thrust fault of the SVU through a multi-scale structural analysis and investigate the evolution of the deformation mechanisms with increasing burial depth. At shallow depth, the thrust developed in poorly lithified sediments which deformed by particulate flow. With increasing depth and lithification of sediments, deformation was accommodated in a meter scale, heterogeneous fault zone, including multiple strands of crack-and-seal shear veins, associated with minor distributed shearing in clay-rich domains and pressure solution. In the last stage, slip localized along a sharp, 20 cm thick shear vein, deactivating the fault zone towards the footwall. The widespread formation of crack-and-seal shear veins since the first stages of lithification indicates that failure along the thrust occurred at high fluid pressure and low differential stress already at shallow depth. Progressive shear localization occurs in the last phases of deformation, at temperatures typical of the transition to the seismogenic zone in active megathrusts. [ABSTRACT FROM AUTHOR]

The aim of this population-based study was to assess the incidence rates of infectious diseases in native- (Italian) and foreign-born (immigrants) populations in a North Italy area, in 2006-2010. Crude, age-specific incidence rates (IRs) and age-standardised rate ratios (SRRs) between foreign- and native-born subjects and their 95 % confidence intervals (95 % CI) were estimated. A total of 32,554 cases of infectious diseases were found (9.9 % in foreign-born subjects). The highest SRRs between foreign- and nativeborn subjects were found for tuberculosis (SRR = 27.1; 95 % CI 21.3-34.3), malaria (SRR = 21.1; 14.6-30.4), scabies (SRR = 8.5; 7.6-9.4), AIDS (SRR = 2.5; 1.8-3.4) and viral hepatitis B (SRR = 3.3; 2.1-5.2). The highest IR was found for AIDS in people from the Americas (IR = 4.57; 95 % CI 2.2-8.4), for malaria and tuberculosis in people from Africa (IR = 13.89; 11.6-16.5 and IR = 11.87; 9.8-14.3 respectively). Therefore immigrants are at a higher risk of acquiring some common infectious diseases compared to the native population in Western European countries. [ABSTRACT FROM AUTHOR]

Rossi E, Villanacci V, Bassotti G, Donato F, Festa A, Cengia G, Grisanti S & Cestari R (2010) Histopathology 57, 81–89 TOPOIIα and HER-2/neu overexpression/amplification in Barrett’s oesophagus, dysplasia and adenocarcinoma Aims: Topoisomerase IIα ( TOPOIIα) and HER-2/neu are chromosome 17q genes coamplified in various cancers; no data exist for Barrett’s oesophagus (BO) and BO adenocarcinoma (ADC). The aim was to investigate gene amplification and protein overexpression of TopoIIα and Her-2/neu in non-dysplastic BO, dysplastic BO, Barrett ADC, and chromosome 17 aneusomy. Methods and results: Forty-four patients [18 BO, 13 BO with dysplasia (five low-grade dysplasia, eight high-grade dysplasia) and 13 ADC in BO] were evaluated by immunohistochemistry and fluorescence in situ hybridization (FISH). Genes ( HER-2/neu and TOPOIIα) and chromosome 17 were evaluated by FISH. Patients with BO, dysplasia and ADC were compared. A significant association was found between TOPOIIα protein overexpression and TopoIIα gene amplification, chromosome 17 aneusomy, HER-2/neu gene amplification and HER-2 protein overexpression as well as between HER-2 protein and HER-2/neu gene, TopoIIα gene and aneusomy for chromosome17, and between the genes TOPOIIα and HER-2/neu. Gene amplification ( HER-2/neu, TOPOIIα), protein overexpression (HER-2/TOPOIIα), and chromosome 17 aneusomy were associated with dysplasia or ADC. Most BO patients showed no amplification/overexpression/aneusomy for the above genes, proteins and chromosome, with no differences between dysplasia and ADC. Conclusions: HER-2/neu and TOPOIIα amplification/overexpression might discriminate between BO and dysplasia/ADC. Chromosome 17 aneusomy is associated with dysplasia or ADC in BO. [ABSTRACT FROM AUTHOR]

We present a detailed description of the tectono-stratigraphic architecture of the eclogite-facies Internal Piedmont Zone (IPZ) metaophiolite, exposed in the Lanzo Valleys (Western Alps), which represents the remnant of the Jurassic Alpine Tethys. Seafloor spreading and mantle exhumation processes related to the Alpine Tethys evolution strongly conditioned the intra-oceanic depositional setting, which resulted in an articulated physiography and a heterogeneous stratigraphic succession above the exhumed serpentinized mantle. "Complete" and "reduced" successions were recognized, reflecting deposition in morphological or structural lows and highs, respectively. The "complete" succession consists of quartzite, followed by marble and calcschist. The "reduced" succession differs for the unconformable contact of the calcschist directly above mantle rocks, lacking quartzite and gray marble. The serpentinite at the base of this succession is intruded by metagabbro and characterized at its top by ophicalcite horizons. Mafic metabreccia grading to metasandstone mark the transition between the "complete" and "reduced" successions. The character of the reconstructed succession and basin floor physiography of the IPZ metaophiolite is well comparable with the Middle Jurassic–Late Cretaceous succession of both the Queyras Complex (External Piedmont Zone) and the Internal Ligurian Units (Northern Apennines) and with modern slow-spreading mid-ocean ridges. [ABSTRACT FROM AUTHOR]

• 3 component gasoline surrogates are usually made from toluene, isooctane and n - heptane. • Gasoline surrogates with toluene, isopentane and n-heptane (THIP) are proposed. • THIP surrogates capture RON/ MON and Ignition Delay (measured in RCM) of a real fuel. • THIP surrogates are better able to represent a realistic DVPE and density. • Chemical kinetic mechanisms exist to model THIP surrogates with reasonable accuracy. Simple surrogate formulations for gasoline are useful for modelling purposes and for comparing experimental results using a carefully designed fuel. Simple three component surrogate fuels based on toluene, n-heptane and isooctane, called toluene primary reference fuels (TPRF), are frequently used to match the RON and MON of actual gasoline fuels. In this work the main advantages of using an alternative three-component surrogate formulation, based on toluene, n-heptane and isopentane (THIP) are presented. Given a reference gasoline, good representations of RON and MON are achieved as well as better matching density, distillation properties and other volatility parameters associated with the lighter end of gasoline fuels. In particular, THIP surrogates can replicate Dry Vapour Pressure Equivalent (DVPE) values ranging from 10.4 kPa to 138.9 kPa, fully covering the EN228 Summer and Winter gasoline specifications. Moreover, Rapid Compression Machine (RCM) results demonstrate that THIP surrogates can reproduce the essential characteristics of the reference gasoline in terms of ignition delay time versus temperature. An existing chemical kinetic mechanism is shown to be able represent THIP surrogate well. [ABSTRACT FROM AUTHOR]

One of the most compelling evidences that megathrust subduction interfaces are weak (e.g. Duarte et al., 2015), is the devastating 2011 Tohoku-Oki megaquake, whereby the megathrust accomplished a nearly complete stress drop (Hasegawa et al., 2011; Brodsky et al., 2017) and a co-seismic switching of the maximum and minimum stress orientations (Hasegawa et al., 2012).We studied the calcite veins of an exhumed thrust fault coming from the base of the Sestola Vidiciatico Tectonic Unit shear zone (SVU, Northern Apennines of Italy), interpreted as a field analogue of the shallow portion of subduction megathrusts (Tmax ̴ 100°-150° C) (Vannucchi et al., 2008). Observed crosscutting relationships suggest a cyclical formation of incompatible deformation features: extensional veins exploiting pre-existent cleavage planes at low-angle to the thrust, the main low-angle thrust faults associated with mixed hybrid-shear and implosion-breccia type veins and high-angle extension veins coupled with thrust-parallel pressure solution cleavage (Mittempergher et al., 2018).To characterize the type of fluids involved, we measured trace elements and Rare Earth Elements (REEs) concentrations by laser ablation-inductively coupled plasma-mass spectrometry (LA-ICPMS) in calcite veins and their wall rock, finding marked difference between REE patterns of extension and shear veins, suggesting different sources of fluid for each type of vein. In particular, a strongly positive Eu2+ anomaly recorded exclusively in the shear veins can derive from an exotic fluid, different in redox conditions and likely higher in temperature. To the contrary, extension veins REE patterns point out for a very local fluid circuit and source.All these microstructural and geochemical features suggest a cyclical shifting of the principal σ1 and σ3 stresses through time. This was controlled by interrelated changes in permeability, fluid pressure and composition and easily achieved thanks to the low differential stress, which represented a necessary condition for extension and hybrid veins formation.References:Duarte J. C., Schellart W. P. and Cruden A. R., 2015. How weak is the subduction zone interface? Geophysical Research Letters, 42, 2664-2673.Hasegawa A., Yoshida K. and Okada T., 2011. Nearly complete stress drop in the 2011 Mw 9.0 off the Pacific coast of Tohoku Earthquake. Earth Planets Space, 63, 703-70.Hasegawa A., Yoshida K., Asano Y., Okada T., Iinuma T. and Ito Y., 2012. Change in stress field after the 2011 great Tohoku-Oki earthquake. Earth and Planetary Science Letters 355-356, 231-243.Brodsky E., Saffer D., Fulton P., Chester F., Conin M., Huffman K., Moore J. C. and Wu H.-Y., 2017. The postearthquake stress state on the Tohoku megathrust as constrained by reanalysis of the JFAST breakout data. Geophysical Research Letters, 44, 8294-8302.Vannucchi, P., Remitti, F. and Bettelli, G., 2008. Geological record of fluid flow and seismogenesis along an erosive subducting plate boundary. Nature, 451, 699-03.Mittempergher S., Cerchiari A., Remitti F. and Festa A., 2018. From soft sediment to fluid assisted faulting at the base of the Sestola-Vidiciatico tectonic Unit in the Northern Apennines (Italy). Geological Magazine, 155(2), 438-450. [ABSTRACT FROM AUTHOR]

The primary stratigraphic fabric of a chaotic rock unit in the Zermatt Saas ophiolite of the Western Alps was reworked by a polyphase Alpine tectonic deformation. Multiscalar structural criteria demonstrate that this unit was deformed by two ductile subduction-related phases followed by brittle-ductile then brittle deformation. Deformation partitioning operated at various scales, leaving relatively unstrained rock domains preserving internal texture, organization, and composition. During subduction, ductile deformation involved stretching, boudinage, and simultaneous folding of the primary stratigraphic succession. This deformation is particularly well-documented in alternating layers showing contrasting deformation style, such as carbonate-rich rocks and turbiditic serpentinite metasandstones. During collision and exhumation, deformation enhanced the boudinaged horizons and blocks, giving rise to spherical to lozenge-shaped blocks embedded in a carbonate-rich matrix. Structural criteria allow the recognition of two main domains within the chaotic rock unit, one attributable to original broken formations reflecting turbiditic sedimentation, the other ascribable to an original sedimentary mélange. The envisaged geodynamic setting for the formation of the protoliths is the Jurassic Ligurian-Piedmont ocean basin floored by mostly serpentinized peridotites, intensely tectonized by extensional faults that triggered mass transport processes and turbiditic sedimentation. [ABSTRACT FROM AUTHOR]

The Paleogene "megabeds" of the Julian-Slovenian Basin are regional, basin-wide deposits, produced by catastrophic carbonate platform collapses. They record the emplacement of a bipartite slide mass behaving as a cohesive blocky/debris flow in the lower part, and as a grain to turbulent flow in the upper part. Several types of primary (sedimentary) soft sediment deformation structures testify fluid overpressure conditions during emplacement. Such structures are identified within a brecciated, fine grained matrix that encloses and intrudes slide blocks and clasts, characterized by NE-, NW- and SW-directed paleo-transport directions, indicating a depositional setting close to the basin margins. Here we present an updated review of some representative megabeds, exposed in the open-pit quarry outcrops of Anhovo (SW Slovenia). In particular, we here discuss new interpretations based on X-ray fluorescence spectrometry (XRF), thermo-gravimetry (TG) and electric resistivity tomography (ERT). Our results indicate that basal marly clasts of the megabeds are markedly different from the uppermost draping marls, suggesting two different coeval sources. The relationships with the underlying successions are strongly erosive, with deep localized scouring of the substrate and amalgamations between different megabeds, and the depositional units inside individual megabeds, supporting the geochemical differences. [ABSTRACT FROM AUTHOR]