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High-MgO lamproite and lamproite-like (i.e. lamprophyric) ultrapotassic rocks are recurrent in the Mediterranean and surrounding regions. They are associated in space and time with ultrapotassic shoshonites and high-K calc-alkaline rocks. This magmatism is linked with the geodynamic evolution of the westernmost sector of the Alpine–Himalayan collisional margin, which followed the closure of the Tethys Ocean. Subduc- tion-related lamproites, lamprophyres, shoshonites and high-K calc-alkaline suites were emplaced in the Medi- terranean region in the form of shallow level intrusions (e.g. plugs, dykes and laccoliths) and small volume lava flows, with very subordinate pyroclastic rocks, starting from the Oligocene, in the Western Alps (northern Italy), through the Late Miocene in Corsica (southern France) and in Murcia-Almeria (southeastern Spain), to the Plio- Pleistocene in Southern Tuscany and Northern Latium (central Italy), in the Balkan peninsula (Serbia and Mac- edonia) and in the Western Anatolia (Turkey). The ultrapotassic rocks are mostly lamprophyric, but olivine latitic lavas with a clear lamproitic affinity are also found, as well as dacitic to trachytic differentiated products. Lamp- roite-like rocks range from slightly silica under-saturated to silica over-saturated composition, have relatively low Al2O3, CaO and Na2O contents, resulting in plagioclase-free parageneses, and consist of abundant K-feldspar, phlogopite, diopsidic clinopyroxene and highly forsteritic olivine. Leucite is generally absent, and it is rarely found only in the groundmasses of Spanish lamproites. Mediterranean lamproites and associated rocks share an extreme enrichment in many incompatible trace elements and depletion in High Field Strength Elements and high, and positively correlated Th/La and Sm/La ratios. They have radiogenic Sr and unradiogenic Nd iso- tope compositions, high 207Pb over 206Pb and high time-integrated 232Th/238U. Their composition requires an originally depleted lithospheric mantle source metasomatized by at least two different agents: (1) a high Th/ La and Sm/La (i.e. SALATHO) component deriving from lawsonite-bearing, ancient crustal domains likely hosted in mélanges formed during the diachronous collision of the northward drifting continental slivers from Gondwana; (2) a K-rich component derived from a recent subduction and recycling of siliciclastic sediments. These metasomatic melts produced a lithospheric mantle source characterized by network of felsic and phlogo- pite-rich veins, respectively. Geothermal readjustment during post-collisional events induced progressive melt- ing of the different types of veins and the surrounding peridotite generating the entire compositional spectrum of the observed magmas. In this complex scenario, orogenic Mediterranean lamproites represent rocks that charac- terize areas that were affected by multiple Wilson cycles, as observed in the Alpine–Himalayan Realm.

We report on results from anisotropy of magnetic susceptibility (AMS) analyses carried out on weakly deformed fine-grained sediments from the Northern Apennine orogenic system (Italy). We sampled 63 sites from preorogenic, synorogenic, and postorogenic sequences, which differ in age, composition, depositional environment, degrees of deformation, and tectonic regimes. The magnetic fabric is typical of weakly deformed sediments, with a magnetic foliation subparallel to the bedding plane and a magnetic lineation well defined in this plane. Northern Apennine chain deposits are characterized by strongly oblate magnetic susceptibility ellipsoids, indicating that the magnetic fabric is the result of both compaction process and tectonic load experienced by the sediments during diagenesis and orogenic events. The orientation of magnetic lineation is significantly different depending whether the studied sites underwent extensional or compressional tectonic regimes. In the Northern Apennine chain, the magnetic lineation is mostly oriented NNW-SSE, parallel to the main compressional structures. It suggests a tectonic origin of the magnetic lineation with an acquisition related to the Apennines compressional phases. In the extensional Tuscan Tyrrhenian margin, magnetic lineation is oriented ENE-WSW, almost perpendicular to the main extensional faults, which represent the main deformation elements of the area. Our results demonstrate a close relationship between the shape and orientation of magnetic fabric and the tectonic history of rocks, confirming that AMS represents a valuable tool to investigate the tectonic history of weakly deformed sedimentary rocks.

During the past few decades, palaeomagnetism has been used as a powerful tool for constraining kinematic models of curved orogenic systems, because of its great potential in quan- tifying vertical axis rotations and in discriminating between primary and secondary (orocline s.l.) arcs. The Mediterranean area has represented an attractive region to apply palaeomagnetic analysis, as it shows a large number of narrow arcs, defining an irregular and rather diffuse plate boundary. This paper is intended to be an updated review on the contribution of palaeomag- netism to the reconstruction of the Neogene geodynamic evolution of the arc-shaped orogenic belts in the Western and Central Mediterranean Basin. The Gibraltar Arc, the Northern Apennines and the Calabria Arc are here described, underlining the common and the different features that char- acterize these arcuate mountain chains. In particular, the mechanisms that lead to the present-day shape of these arcs (the subduction process) will be discussed, in the general framework of the geometry and space–time evolution of the Mediterranean subduction system.

The Miocene Cabo de Gata volcanic arc in SE Spain comprises a wide variety of volcanic facies and eruptive styles in subaqueous to subaerial environments. In the SW sector of the area, 5–100 m-thick, NNW–SSE-orientated dykes feed and intrude submarine hyaloclastite deposits. We analysed the anisotropy of magnetic susceptibility (AMS) of six dykes and five hyaloclastite sites from three volcanic units: the Cerro Can˜adillas, Los Frailes, and El Barronal formations. The main magnetic minerals are primary low-Ti titanomagnetite and magnetite. The AMS ellipsoids in the dykes are generally oblate-triaxial in shape, with magnetic foliations subparallel to the dyke walls. Kinematic field evidence supports the inferred flow directions deduced from magnetic lineation and imbrication of magnetic foliation. The geometric relationships between dyke margins and AMS axes indicate that dykes at El Barronal were emplaced via prevalent subvertical upward magma flow. The inferred flow directions are reproduced well by analogue models of AMS simulating magma migration in dykes with a diapiric geometry. The other dykes were emplaced by lateral magma propagation. Conversely, hyaloclastite shows a large scatter of the AMS axes reflecting different degrees of fragmentation. We observe a gradual increase in scatter in the AMS from confined dykes to fragmented hyaloclastite.

In this study we use the anisotropy of magnetic susceptibility (AMS) and paleomagnetic data for deciphering the origin of magnetic lineation in weakly deformed sedimentary rocks and for evaluating oroclinal processes within the Arabia-Eurasia collision zone. In particular, we have analyzed the Miocene Upper Red Formation (URF) from the outer curved front of the southern Central Alborz Mountains of north Iran, to test for the first time with paleomagnetic data the origin (primary versus secondary) of this orogenic arc. AMS data document the existence of a magnetic lineation parallel to the orientation of the major tectonic structures, which vary along strike from WNW to ENE. These directions are highly oblique to the paleoflow directions and hence suggest that the magnetic lineation in the URF was produced by compressional deformation during layer-parallel shortening. In addition, our paleomagnetic data document clockwise and anticlockwise rotations along vertical axis for the western and eastern sectors of the Central Alborz Mountains, respectively. Combined, our results suggest that the orogen represents an orocline, which formed not earlier than circa 7.6Ma most likely through bending processes caused by the relative motion between the rigid crustal blocks of the collision zone. Moreover, our study provides new insights into the Iran-Southern Caspian Basin kinematic evolution suggesting that the present-day SW motion of the South Caspian Basin with respect to Central Iran postdates oroclinal bending and hence cannot be as old as late Miocene to early Pliocene but a rather recent configuration (i.e., 3 to

Anisotropy of magnetic susceptibility (AMS) data reveal heterogeneous pyroclastic flow processes and variable flow directions within the intra-caldera setting of the Permian rhyolitic welded Ora ignimbrite. Magnetic fabric is primary, orientated during the pyroclastic flow emplacement, and is controlled by paramagnetic and ferromagnetic mineral phases. The ignimbrite has typically weak mean magnetic susceptibilities (1.32–21.8 × 1024 SI) but with a large spread and low anisotropy degrees (1.003–1.023), which vary in different parts of the caldera. The intracaldera magnetic fabric provides significant information on the dynamics of the intra-caldera setting, relating to changing vertical and lateral flow emplacement processes.AMSshape ellipsoids range from oblate to prolate; these are interpreted to reflect the heterogeneous nature of the flow resulting from the influence of underlying topography, constraints of the caldera walls, primary welding and post-emplacement mineral growth. We have identified different depositional units and possible eruptive source regions, indicating that more than one source fissure vent was active during eruption within this caldera system. The lateral variations demonstrate a meandering of flow pulses. The caldera margin acts as an obstacle in preventing and rebuffing certain flows from scaling the caldera margin.

We report on an extensive paleomagnetic study (36 sites) of the Tuscan Nappe succession from the Northern Apennines Arc, aimed to reconstruct the tectonic evolution of the internal sector of this chain. We analyzed Eocene pelagic foreland ramp deposits (Scaglia Toscana Formation) and Oligocene–lower Q1 Miocene siliciclastic turbidites (Macigno and Falterona Formations). Paleomagnetic results show that the internal sector of the Northern Apennines underwent large counterclockwise (CCW) rotations with respect to the Adria-Africa foreland. A decrease in the rotation magnitude was observed from the southern to the northern sector of the arc (from 91 to 36°). This trend is opposite to that observed in the more external units of Northern Apennines and demonstrates that the oroclinal bending model, which has been proposed for the external units of the chain, is not appropriate to explain the evolution of the internal sector of the arc. On the basis of the observed paleomagnetic pattern, we propose a new tectonic model in which the Tuscan and Falterona-Cervarola units in the southern area were first rotated CCW along with the Corsica-Sardinia block during its lower Miocene rotational drifting and were later involved in the main phases of rotational emplacement and translation toward the outermost sector (Umbria domain), thus yielding the final curved shape of the Northern Apennines chain. Data from this study represent the first paleomagnetic evidence of the influence of the Corsica-Sardinia CCW rotation in the Apennines orogenic wedge deformation, in the general framework of the geodynamic evolution of the Central Mediterranean subduction system.

La ricostituzione della filiera produttiva e la tracciabilità dell’intero percorso degli alimenti dalla produzione alla vendita sono divenuti una parte essenziale della ricerca nel campo dell’agroalimentare, soprattutto per gli alimenti di pregio. Tra questi il vino è sicuramente il prodotto che è stato oggetto di maggiore attenzione, anche in considerazione del progressivo sviluppo dei marchi DOC e DOCG e dell’importanza economica assunta dal concetto di Terroir, che ne definisce l’inscindibile legame con il territorio come elemento determinante per la sua valorizzazione economica. La comunità scientifica e gli organismi internazionali hanno dedicato grande attenzione alla messa a punto di metodologie scientifiche e tecnologie idonee alla certificazione di qualità dei vini di pregio. Le analisi dei rapporti isotopici di elementi leggeri (idrogeno, carbonio e ossigeno) sono diffusamente utilizzate per il controllo dell’autenticità del vino e sono state inserite in regolamenti CEE e nazionali. Quest’analisi non è tuttavia risolutiva per il riconoscimento e la tracciabilità geografica del vino a causa della loro forte dipendenza da fattori climatici locali e dall’andamento atmosferico stagionale. Per questo motivo la ricerca si è indirizzata verso lo studio di elementi caratteristici del sistema substrato/suolo di provenienza con l’obiettivo di risalire dalla composizione chimico-fisica del prodotto vino al suo areale (territorio) d’origine. Infatti la composizione chimica e isotopica della matrice inorganica è legata alla natura del suolo di impianto della vigna, che eredita le proprie caratteristiche composizionali e qualitative direttamente dal substrato geologico e dunque può rappresentare la sua impronta digitale e fornire uno strumento efficace per la sua tracciabilità.

""The geological mapping of the sheets 366 “Palombara Sabina” and 375 “Tivoli” (1: 50.000 scale; CARG Project; in preparation) allowed the revision of the structural setting of the westernmost portion of this part of the Neogene fold-and-thrust belt of the Central Apennines.. The area comprises the Cornicolani, Lucretili, eastern Sabini, Tiburtini, Ruffi and Prenestini Mts (Latium region). Most of the area (Cornicolani, Lucretili and Tiburtini Mts) is made of the pre-orogenic deposits (Upper Triassic-Serravallian) referred to the calcareous-marly-siliceous Sabina Succession, that were accumulated in the southern part of the Umbria-Marche-Sabina Pelagic Basin (Sabina Domain), proximal to the Latium-Abruzzi Carbonate Platform. In general, in the eastern areas, more proximal to the platform, coarser lithofacies crop out. Moreover, in the Cornicolani and western Lucretili Mts (Castelvecchio Mt) areally restricted outcrops of condensed pelagic carbonates (Bugarone Group and calcari dolomitici di S. Angelo Romano) document the occurrence of Jurassic intrabasinal structural highs evolved into Pelagic Carbonate Platforms. These structural highs were generated after the Early Jurassic rifting, that broke-up the pre-existing carbonate platform (Calcare Massiccio).. In the mapped area, the Latium - Abruzzi Platform is represented in the hangingwall of the Olevano-Antrodoco line only in the southern Prenestini Mts (Rocca di Cave), by upper Cretaceous shelf carbonates. Whereas in the footwall of the Olevano-Antrodoco line it crops out along the Aniene River valley.. Both Sabina and Latium - Abruzzi successions are overlain by upper Tortonian - lower Messinian marls and siliciclastic syn-orogenic deposits, best observed in the easternmost areas and inbetween the Ruffi and Prenestini Mts.. In their turn, the syn-orogenic deposits are unconformably overlain by post-orogenic Plio-Pleistocene marine clastic deposits and Quaternary volcanic and alluvial sediments. From a structural point of view, the Sabina Domain is arranged into several thrust sheets verging toward the east, developed in middle-late Miocene-early Pliocene times. The early Pliocene Olevano-Antrodoco out-of-sequence thrust marks the eastern tectonic boundary of this structural domain where the pelagic and slope sediments overthrust the Latium - Abruzzi Carbonate Platform and its associated syn-orogenic deposits. In late Miocene-early Pliocene extensional tectonics down-threw the western border of this imbricated structure enhancing the marine ingression along the peri-Tyrrhenian margin. The western border of the region was also reactivated by N-S right-lateral strike-slip fault dissecting the earlier structures in Pleistocene times.. From top of the orogenic edifice three main tectonic units have been identified:. - Unit 1 (Morra Mt) made up of Upper Triassic to Lower Jurassic dolomite limestones (Dolomia Principale) and Calcare Massiccio, overthrust onto unit 2.. - Unit 2 (comprising Cornicolani Mts, western Lucretili Mts) made up of Dolomia Principale, Calcare Massiccio, Corniola detritica and, in the Cornicolani and western Lucretili Mts, Bugarone Group. Long wavelength upright folds mainly characterize this unit and faults with high angle cuts-offs prevail, and Jurassic structural highs occur (Cornicolani Mts, Castelvecchio Mt).. - Unit 3 (comprising Elci Mt, eastern Lucretili Mts and Tiburtini Mts) made up of most of the Sabina basin stratigraphic succession - from Corniola detritica Fm. to the Guadagnolo Member (marly lithofacies); the unit is characterized by NW to NE verging overturned to recumbent folds. - Unit 4 (comprising Prenestini Mts, Ruffi Mts and eastern Sabini Mts) made up of the upper portion of the basin succession between the Marne a Fucoidi and Upper Miocene siliciclastics and the Rocca di Cave carbonate platform succession.. This unit is made up by two sub-units, based on the deformation-style and stratigraphy: the sub-unit 4A (Granaro Mt, Colle Serviano and Arzillo Mt in the western Prenestini Mts), is mainly characterized by east-verging packed asymmetrical folds with sub-vertical axial-planes, and N-S striking dextral-transpressive faults. The sub-unit 4B (Castel Madama area, eastern and central Prenestini Mts, Ruffi Mts and eastern Sabini Mts) is characterized by a wide symmetrical anticline in the western portion, and by folds with very steep axial planes, and N-S to NNW-striking dextral transpressional faults.. The units are separated by low-angle thrusts or by high-angle transpressive faults: the stratigraphic successions characterizing each unit rejuvenate eastward.. The innermost unit 1 and unit 2, where massive or poorly stratified deposits are exposed, are mainly deformed by high angle faults. Whereas the more external unit 3 and unit 4 are composed by alternating carbonate, marls and siliciclastics, and are mostly characterized by east-verging slightly to strongly asymmetrical and overturned folds.. A new geometric and kinematic scenario for the Neogene evolution of the units preserved in the hangingwall of the Olevano-Antrodoco thrust is here outlined.. The revision of the stratigraphy and structural data put in evidence the presence of paleo-structures of the Tethyan passive margin not evidenced in the past cartography, their influence on Neogene compressive structures and the coexistence of non-coaxial structural trends in areas of limited extension."" ""Il rilevamento dei fogli geologici 366 “Palombara Sabina” e 375 “Tivoli” (Progetto CARG) ha comportato la revisione dell’interpretazione dell’assetto strutturale della porzione più occidentale dell’Appennino Centrale. L’area esaminata comprende i Monti Cornicolani, Lucretili, Sabini orientali, Tiburtini, Ruffi e Prenestini, caratterizzati dall’affioramento di depositi meso-cenozoici pre-orogenici di piattaforma carbonatica annegata, di bacino, di transizione (Dominio paleogeografico Sabino) e di piattaforma carbonatica persistente (Piattaforma Laziale-Abruzzese), e di depositi sin-orogenici silicoclastici miocenici. Le unità tettoniche del Dominio Sabino si accavallano su quelle della Piattaforma Laziale-Abruzzese lungo la Linea Olevano-Antrodoco Auctorum.. Il Dominio Sabino è stato suddiviso in quattro Unità tettoniche (partendo da quella superiore):. Unità 1 (M. Morra);. Unità 2 (Monti Cornicolani, Monti Lucretili occidentali);. Unità 3 (M. degli Elci, Monti Lucretili orientali, Monti Tiburtini);. Unità 4 (Monti Sabini orientali, Monti Ruffi, Monti Prenestini), in cui si distinguono la sub-unità 4A (Monti Prenestini occidentali) e la sub-unità 4B (Monti Sabini orientali, di Castel Madama, Ruffi e Prenestini centro orientali).. In questo assetto strutturale, le principali novità riguardano l’individuazione di paleostrutture giurassiche (in particolare un alto strutturale nei Monti Lucretili occidentali), la loro influenza sullo sviluppo della deformazione compressiva, e una più dettagliata definizione di trend compressivi non-coassiali già evidenziati nella presistente cartografia.""

Southern Apennines is characterized by active extensional tectonics with NE–SW stretching direction. The seismicity of the region is very well understood and continuously monitored. In contrast, the onset of extensional tectonics is chronologically poorly constrained. The aim of this study is that to give important constraints on the development of extensional regime and the onset of the continental deposition during Quaternary in Southern Apennines. We report the results of palaeomagnetic and rock magnetic analyses from four Quaternary small intramontane basins in the PicentiniMountains (Southern Apennines). The sedimentary sequences are located at different altitudes, from 600 to 1200 m a.s.l., and were deposited in fluvial-lacustrine environments. We sampled 29 sites in clays and lacustrine limestones from Tizzano, Piano del Gaudo and Acerno basins and in red palaeosoils and matrix-supported conglomerates from the Iumaiano basins. In the clay and limestones samples magnetite, titano-magnetite, hematite and iron-sulphide have been recognized as the main magnetic carriers, whereas magnetite and hematite characterize the Iumaiano conglomerates and red soils. Palaeomagnetic results have been integrated with published radiometric data in order to constrain the age of each sedimentary basins. Sites from the Iumaiano basin, which represents the substrate of the Tizzano and Piano del Gaudo basins, show a reverse polarity and therefore have been attributed to the lower Matuyama chron. In contrast, palaeomagnetic data from Tizzano basin show a transition from reversed to normal polarity along the exposed section, which has been interpreted as the Matuyama/Brunhes transition. Sites from Acerno and Piano del Gaudo basins show a normal polarity, which, according to radiometric and pollen data, have been correlated to the Brunhes epoch. On the base of such results we discuss the tectonostratigraphic evolution of the basins and the role of extensional tectonics in this portion of the Southern Apennine during the Quaternary.

The Colli Albani volcano has been active since c. 600 ka and is presently quiescent. Rock stratigraphy indicates that the activity of the volcano has undergone major changes in terms of eruption style, average eruption rate and location of active vents. The chemistry of the Colli Albani products is remarkably mafic, K-rich and silica undersaturated. Nevertheless, the volcano has experienced all types of eruption styles, from plinian explosive paroxysms, to milder strombolian and hawaiian eruptions, to effusive, including large- and small-scale phreatomagmatism. The first period of activity of the volcano is termed the ‘Vulcano Laziale’ period, and lasted from c. 600 ka to c. 355 ka. During this period, the volcanism was predominantly explosive, with an average eruption rate of 1 km3 ka21. At least seven intermediate- to large-volume ignimbrites (VEI 5–7) were erupted and emplaced over an area larger than 1600 km2, forming an extensive ignimbrite shield around the central, continuously forming c. 8 8 km2 caldera. The caldera complex and the ignimbrite shield are named the ‘Vulcano Laziale edifice’. The Vulcano Laziale edifice can in turn be subdivided into a lower ‘Pisolitic Tuffs succession’ (c. 600– 500 ka), in which ignimbrites are dominated by large-scale phreatomagmatism associated with the likely presence of an early caldera lake, and an overlying ‘Pozzolane Tuffs succession’, in which ignimbrites show a dominantly magmatic fragmentation style, probably in response to progressive exhaustion of the caldera lake. The typical succession of these mafic ignimbrites is composed of a sub-plinain to plinian basal scoria fall deposit covered by the main dark scoria and ash tabular ignimbrite sheet found as far as.30 km from the caldera rim and across ridges several hundreds metres in elevation, and is characterized by co-ignimbrite breccias at proximal locations. Major ignimbrites erupted with an average interval of c. 40 ka. After each paroxysmal ignimbrite eruption, volcanic activity was predominantly effusive to mild explosive, and was concentrated along peri-caldera fissure systems, forming continuous scoria cone and lava ridges, together with more explosive eruptions from intracaldera vents. The last major caldera-forming eruption of the Vulcano Laziale period occurred at c. 355 ka, emplacing the ignimbrites of the Villa Senni formation. Following this eruption, the complex Tuscolano-Artemisio peri- and extracaldera fissure system, predominantly composed of scoria cones and lavas, formed in response to the deflation of the caldera and peri-caldera area, together with formation of the intracaldera Faete stratovolcano. These edifices were emplaced between c. 355 and c. 180 ka, an interval termed the ‘Tuscolano–Artemisio–Faete period’. Although similar peri-caldera and intracaldera activity occurred earlier, that is, after each major caldera-forming eruption during the Vulcano Laziale period, the Tuscolano–Artemisio–Faete period was subject to a significant reduction in average eruption rate, by one order of magnitude, of 0.1 km3 ka21, which can be related to a consistent reduction in the deep recharging of the plumbing system, and suggesting why no further ignimbrite eruptions occurred after 355 ka. Peri-caldera activity began along the northern and eastern peri-caldera ring fractures (Tuscolano and Artemisio sections, respectively) and after c. 300 ka progressively migrated outwards to extracaldera positions (Pantano Borghese section) and to the western peri-caldera fractures (S. Maria delle Mole section). The activity of these latter fracture systems ended almost simultaneosly, together with that of the Faete intracaldera stratovolcano, between c. 280 and c. 250 ka. After 250 ka, activity migrated to the south (Monte Due Torri section). The most recent activity along this latter peri-caldera area interfingers (between c. 200 ka and c. 180 ka) with phreatomagmatic products, which instead became dominant in the most recent activity of the Colli Albani volcano. Beginning from c. 200 ka (Via dei Laghi period), the western section of the pericaldera area has been the site of repeated very small- to small-volume, maar-forming phreatomagmatic eruptions, which formed both monogenetic and polygenetic maars, collectively named the Via dei Laghi maar field. The most recent of these maars is the polygenetic Albano maar, which was formed after c. 70 ka by at least seven eruptions migrating along a NW–SE-trending, 3.5-km-long fracture. The last eruption of the maar occurred at ,23 ka. Subsequent phreatic activity occurred throughout the Holocene, with lahars originating from dramatic withdrawals of the deep maar lake, at least up to the Eneolithic time (6000–5000 years ago) and probably up to Roman times (fourth century BCE), when the Romans dug a tunnel drain to keep the lake at a constant low level. The Albano area is currently the site of volcanic gas emissions, ground uplift and periodic seismic swarms, which may indicate persistent activity of a magmatic body at depth.

In this paper we describe the structural architecture of the Colli Albani from the sedimentary cover to the upper mantle. The regional stratigraphy, deep wells and sedimentary xenoliths embedded in the pyroclastic deposits have been considered in order to constrain the composition and structure of the sedimentary substratum, whereas the lithospheric structure of the volcano has been investigated using seismic tomography and receiver function analyses. The main features at depth are a sub-horizontal Moho located at 20 – 24 km and a low velocity in the uppermost mantle. The Moho separates two anisotropic regions, one located in the uppermost mantle and a second in the lower crust. The anisotropic fabric can be interpreted as being due to a sub-vertical flux in the mantle coherent with the magma uprise from a mantle source. Seismolo- gical analyses do not discriminate velocity reductions ascribable to melt in the shallow crust. An intrusive body, which up-domed the limestone layer, is present beneath the central part of the volcano at depths greater than 5 km. These data are in agreement with the position of the magma chamber deduced by the presence of thermo-metamorphic xenoliths related to dolostone and limestone protolithes, which represent the lowermost portion of the Mesozoic – Cenozoic sedimentary sequence

The Colli Albani volcano belongs to the Roman Magmatic Province and is character- ized by strongly silica undersaturated leucite-bearing ultrapotassic rocks. Melilite-bearing leuciti- tic lavas, beside tephritic to tephritic phonolitic ignimbrites, were erupted during the pre-caldera (Vulcano Laziale) period. The post-caldera phase opened with magmas erupted from different feeding systems, with melilite-bearing leucitites in the early phases followed by tephritic and pho- nolitic tephritic lavas. The late-stage activity (i.e. the Via dei Laghi period) is characterized by hydromagmatic tuffs with small juvenile fragments that prevent a clear compositional definition of the magma triggering the eruptions. Despite their mineralogical and compositional similarities, the Vulcano Laziale period (pre-caldera) has significantly higher levels of incompatible trace elements and 87Sr/86Sr isotopes than found in magmatic rocks erupted after the caldera formation. Pre- and post-caldera parental magmas are considered to be significantly different from each other and generated within a metasomatized upper mantle under different degrees of partial melting. Crustal-derived carbonate-rich metasomatism is thought to have affected the mantle wedge of the Italian peninsula. Melting of pelitic sediments with different amounts of CaCO3 is considered the source of the metasomatic agents, which are able to re-fertilize the lithospheric upper mantle. Partial melting of this modally metasomatized lithospheric mantle under high XCO 2 produced the strongly silica undersaturated ultrapotassic magmas observed at the Colli Albani volcano. A second-order differentiation process occurs at shallow levels, with fractional crystallization and crustal assimilation of wall rock (AFC), locally changing the compositions of magmas and pro- ducing several differentiation pathways that have given rise to the geochemical and petrological complexity of the Colli Albani volcano. Assimilation of carbonate sediments and silicoclastic sedimentary lithologies also occurred coevally, suggesting the existence of several separate magmatic reservoirs at shallow levels, possibly at different depths and surrounded by different sedimentary formations.

We present an up-to-date review of the existing data on the evolution of the Apennine– Tyrrhenian basin system and of the tectonic models developed to interpret the complex evolution of magmatism and volcanism along the Tyrrhenian margins of peninsular Italy from Miocene to the Present. The Tyrrhenian margin volcanic belt lies within a back-arc basin located on top of the NW-dipping Adriatic–Ionian slab, active along the convergent boundary between the Africa and Eurasia plates. It is characterized by significant crustal thinning, high thermal flow and huge production of mantle fluids. Seismic activity is very low and clusters in geothermal and volcanic areas. The structural architecture of the extensional Tyrrhenian margin is mainly controlled by NW–SE oriented normal faults, which are presently active along the Apennine water shade. This volcanism can be divided on the basis of time–space and petrographic criteria into four different provinces: the Corsica Magmatic Province, the Tuscan Magmatic Province, the Roman Magmatic Province and the Lucanian Magmatic Province. Inside each of these magmatic regions, igneous rocks with different petrochemical affinities are found in the same timespan beside the main magmatic association. The structural control over the Roman Magmatic Province volcano locations and spacing can be divided into two main components: the geometry of the mantle source, which defines the general trend of the volcanic chain, and the structure of the crust, which defines zones of preferential permeability to magmatic fluids. On a crustal scale, the localization of volcanoes is ubiquitously related to cross-cutting NW-trending and NE-trending transverse extensional structures. Volcanoes of the Tyrrhenian margin show a variety of morphologies and eruption styles. In particular, Middle–Upper Pleistocene volcanoes of the Roman Magmatic Province display both effusive and explosive activity. Highly explosive volcanoes have erupted several intermediate- to large-volume ignimbrites and are characterized by large, polyphased calderas and vast ignimbrite plateaus. Volcanoes characterized by intermittent effusive and explosive activity have formed stratovolcanoes and also erupted intermediate-volume ignimbrites that generally formed small summit collapse composite calderas.

High-MgO ultrapotassic rocks are found in four different areas of the Western Mediterranean basin associated in space and time with shoshonitic and calc-alkaline rocks. They represent different magmatic events at the active continental plate margin from Oligocene to Pleistocene. These rocks are found within the Western Alps (Northern Italy), in Corsica (France), in Murcia-Almeria (South-Eastern Spain), and in Southern Tuscany (Central Italy). Ultrapotassic terms are mostly lamprophyres, but olivine latitic lavas with a clear lamproitic affinity are also found. Lamproite-like rocks range from slightly silica under-saturated to silica over-saturated, and they are characterised by low Al2O3, CaO, and Na2O contents. They are plagioclase-free rocks, but K-feldspar is abundant beside other K-bearing phases. Shoshonitic and calc-alkaline rocks are invariably space associated to lamproites, and they either precede or follow them. High-Mg ultrapotassic rocks are characterised by strong enrichment of incompatible elements, which prevent further enrichment due to shallow level crustal contamination. K2O and incompatible element contents decrease passing from high-Mg ultrapotassic to high-Mg shoshonitic and calc-alkaline rocks suggesting that K and incompatible trace elements enrichments are a primary characteristic. Ultrapotassic to calc-alkaline rocks from Western Mediterranean regions, in spite of their different age of emplacement, are characterised by similar incompatible trace elements distribution. Depletion of High Field Strength elements with respect to Large Ion Lithophile elements is observed. Positive spikes at Th, U, and Pb, with negative spikes at Ba, Nb, Ta, Sr, P, and Ti, are common characteristics of ultrapotassic (lamproitic) to high-K calc-alkaline rocks. Ultrapotassic rocks are extremely enriched in radiogenic Sr and unradiogenic Nd with respect to the associated shoshonitic and calc-alkaline rocks. Different isotopic values are distinctive of the different magmatic provinces irrespective of magmatic affinities. 87Sr/86Sri ranges between 0.71645 and 0.71759 for Western Alps lamproites, between 0.71226 and 0.71230 for Corsica lamproite, between 0.71642 and 0.72259 for Murcia-Almeria lamproites, and between 0.71578 and 0.71672 for Tuscany lamproites. Radiogenic Sr decreases along with K2O through shoshonitic to calc-alkaline rocks. Conversely 143Nd/144Ndi values increase with decreasing K2O, with the highest value of 0.51243 found for the one samples from Murcia-Almeria. Contrasting trends are observed among initial values of lead isotopes, but all falling well within the field of upper crustal rocks. Different trends of 207Pb/204Pbi and 208Pb/204Pbi vs. 206Pb/204Pbi for samples from the different provinces are observed. Several evidences indicate that most of the magmas of the different provinces have been generated in a depleted upper mantle (i.e., lithospheric) modified by metasomatism, but an asthenospheric component is also recognised in Corsica. At least two different subduction-related metasomatic agents re-fertilised the depleted original upper mantle source. Carbonate-free siliciclastic sediments and carbonate-rich sediments have been recycled within the upper mantle through subduction and partial melting. Assuming that metasomatic component is concentrated in a vein network, in Tuscany and Corsica, time relationships indicate that low degree of partial melting of the pure vein produced lamproitic-like magmas, whereas an increase in the partial melting involve the surrounding upper mantle, then diluting the alkaline component and produced the entire spectra of magma observed. In South-Eastern Spain calc-alkaline magmatism preceded lamproitic ones, and might be generated by partial melting of mantle wedge metasomatised by fluids from oceanic slab prior to collision. Lamproitic magmas followed after melt-dominated metasomatic agents invaded the lithospheric upper mantle domain. Migration of the magmatism with time is the result of eastward migration of subduction with subsequent opening of Balearic, Ligure-Provençal, and Tyrrhenian basins.

Paleomagnetic, rock magnetic and micro-textural analyses from a Middle Pleistocene lacustrine sequence in the southern Apennines (Italy) indicate the presence of greigite and magnetite as the main magnetic minerals at different stratigraphic levels. In all cases a normal polarity characteristic remanent magnetization (ChRM) was observed, in agreement with an 40Ar–39Ar age of 0.712 ± 0.018 Ma from volcaniclastic sanidine. After correction for bedding tilt, ChRM directions carried by greigite do not coincide with the expected geocentric axial dipole field direction at the site latitude, whereas the magnetite ChRMs directions do. The data indicate that the greigite magnetization was acquired after tilting and after lock-in of the magnetite ChRM. The estimated delay for the remanence carried by greigite with respect to deposition is 300 ka. Scanning electron microscope analyses indicate that alteration of detrital volcanic minerals has occurred and that authigenic greigite is generally present in agglomerates and around volcanic grains. This observation is consistent with a late diagenetic origin of greigite due to anoxic conditions and availability of dissolved sulfide associated with decomposition of organic matter in the paleolake. Documentation of a late diagenetic magnetization confirms that care should be taken when using greigite-bearing sediments for magnetostratigraphic and tectonic studies. Citation: Porreca, M., M. Mattei, and G. DiVincenzo (2009), Post-deformational growth of late diagenetic greigite in lacustrine sediments from southern Italy

The “Colli Albani” composite volcano is made up of strongly silica-undersaturated leucite-bearing rocks. Magmas were erupted during three main periods, but a complex plumbing system dominated by regional tectonics channelled magmas into different reservoirs. The most alkali-rich magmas, restricted to the caldera-forming period (pre-caldera), are extremely enriched in incompatible trace elements and display more radiogenic Sr (87Sr/86Sr = 0.71057–0.71067), with slightly less radiogenic Pb with respect to those of the post-caldera period. Post-caldera volcanic activity was concentrated in three different volcanic environments: external to the caldera, along the caldera edge and within the caldera. The post-caldera magmas produced melilite- to leucitite-bearing, plagioclase-free leucitites. In contrast to the pre-caldera lavas, they are characterised by lower incompatible trace element abundances and less radiogenic Sr ( 87 Sr / 8 6Sr = 0. 71006–0. 71039) . Magmas evolved through crystal fractionation plus minor crustal assimilation in a large magma chamber during the pre- caldera period. The multiple caldera collapses dissected and partially obliterated the early magma chamber. During the post-caldera stage, magmas were channelled through several pathways and multiple shallow-level magma reservoirs were established. A lithospheric mantle wedge previously depleted in the basaltic component and subsequently enriched by metasomatic slab-derived component is suggested as the mantle source of Colli Albani parental magmas. Two different parental magmas are recognised for the pre- and post-caldera stages. The differences may be related to the interplay between smaller degrees of melting for the pre-caldera magmas and more carbonate-rich recycled subducted lithologies in the post-caldera magmas.

A pattern of shifting current direction is revealed by the anisotropy of magnetic susceptibility (AMS) in the quartz latite ignimbrite associated with the Pleistocene Cimini dome complex in central Italy. High-field AMS documents that both paramagnetic and ferrimagnetic minerals contribute to the magnetic fabric of the ignimbrite. The results of low field AMS studies suggest that the pyroclastic density current changed both direction and character during deposition of each flow unit that makes up the ignimbrite. The meandering behaviour of the currents can be observed on the scale of 15-cm increments in the fine-grained basal ‘layer 2a’ of one flow unit in an area lacking significant palaeotopography. AMS data from 1-, 2-, and 4-metre increments through the flow units also show complex changes in flow direction throughout the deposition of each unit studied. The most closely aligned AMS fabrics occur near the bases of flow units, and dispersion increases upward. This trend may represent decreased shear between the flow and the substrate or increased turbulence in the upper depositional zone of the pyroclastic density current, or both, suggesting a progressively waning current (in terms of capacity or particle concentration). The phenomena observed in this study have broad implications for the general methodology of AMS studies. Detailed vertical profiles made up of several individual sample sites within 1-metre thickness intervals can reveal small-scale current ow variations that may not be evident if sampling is done more sparsely.

A pattern of shifting current direction is revealed by the anisotropy of magnetic susceptibility (AMS) in the quartz latite ignimbrite associated with the Pleistocene Cimini dome complex in central Italy. High-field AMS documents that both paramagnetic and ferrimagnetic minerals contribute to the magnetic fabric of the ignimbrite. The results of low field AMS studies suggest that the pyroclastic density current changed both direction and character during deposition of each flow unit that makes up the ignimbrite. The meandering behaviour of the currents can be observed on the scale of 15-cm increments in the fine-grained basal ‘layer 2a’ of one flow unit in an area lacking significant palaeotopography. AMS data from 1-, 2-, and 4-metre increments through the flow units also show complex changes in flow direction throughout the deposition of each unit studied. The most closely aligned AMS fabrics occur near the bases of flow units, and dispersionincreases upward. This trend may represent decreased shear between the flow and the substrate or increased turbulence in the upper depositional zone of the pyroclastic density current, or both, suggesting a progressively waning current (in terms of capacity or particle concentration). The phenomena observed in this study have broad implications for the general methodology of AMS studies. Detailed vertical profiles made up of several individual sample sites within 1-metre thickness intervals can reveal small-scale current flow variations that may not be evident if sampling is done more sparsely.

Paleomagnetic data collected in the last 30 years indicate that a simple orocline model is not sufficient to describe the complex evolution of the Calabrian Arc. Present-day curvature of the Calabrian Arc is the result of a different tectonic history between the edges of the arc, namely the Southern Apennines and Sicily, and its core, the Calabria-Peloritani Domain. These differences mirror the structural architecture and deep lithospheric configuration of the Calabrian Arc, which are related to the geometry and evolution of the Ionian subduction system. In particular, the presence of lateral heterogeneities in the subducting lithosphere and the subsequent progressive decrease in width of the trench during subduction are likely the main causes of Calabrian Arc formation and of its present-day narrow tight shape

The Hyblean Plateau in southeastern Sicily, Italy, consists of an isolated and elevated forebulge structure formed since the early Miocene time by bending the foreland lithosphere below the advancing Maghrebian thrust-fold belt. The Hyblean forebulge is presently located in front of an orogenic recess and partly surrounded by two orogenic salients. We analyzed magnetic (anisotropy of magnetic susceptibility) and structural (joints, faults, slickenside lineations, and bed attitudes) fabric data from Neogene carbonate rocks exposed atop the Hyblean forebulge. Results showed unidirectional fabrics developed in response to a NW-SE extension at the end the of early Miocene time and beginning of middle Miocene time, and duple-to-multiple fabrics developed in response to major NW-SE and NE-SW extensions from the Langhian time onward. We interpreted these results as the evidence for the growth of a doubly plunging forebulge due to the presence of foreland crustal heterogeneities, which enhanced differential retreating processes of the foreland along the subduction zone and the subsequent formation of orogenic salients and recesses. A semianalytical model shows that the observed brittle deformations potentially involved a significant thickness of the carbonate sedimentary cover, thereby reducing the lithosphere flexural rigidity and enhancing its bending aptitude.

Dikes provide important information on the structure, state of stress and activity of a volcano. Mt. Somma borders part of the Vesuvio cone (Italy), displaying ~100 dikes emplaced between ~18-30 ka. Field, AMS (Anisotropy of Magnetic Susceptibility) and thin section analyses are used to characterize their geometry and kinematics (direction and sense of flow). The dikes mostly have a NNW-SSE to NE-SW strike. Approximately 57% are radial to the older Somma edifice, ~27% are oblique and ~16% tangential. Among the latter two groups, ~32% are outward dipping and ~11% inward dipping. The dike thickness varies between 0.2-3 m, with a mean value of 1.17 m. The kinematics of 19 dikes is determined through a combination of field (8 dikes), AMS (16 dikes) and thin section analyses (15 dikes). Thirteen dikes have a vertical upward flow, whereas six have an oblique-subhorizontal flow, suggesting a lateral propagation from the summit or eccentric vents of the former Somma edifice. These propagation paths differ from those deducible from the recent activity, as all the 7 major fissure eruptions between 1631-1944 were related to the lateral propagation of radial dikes. We propose that these different behaviours in dike propagation may be mainly related to the opening conditions of the summit conduit. The laterally propagating dikes in 1631-1944 formed with an open conduit. Conversely, the vertically propagating dikes may have formed, between 18-30 ka, with a closed conduit.

An integrated approach was used to detect tectonic effects in apparently undeformed fine-grained clay sediments filling extensional basins in Southern Italy. Results from low and high field anisotropy of magnetic susceptibility and mineral fabric, deduced by neutron texture analysis, show penetrative deformation on a grain-scale. The well-defined tectonic magnetic lineation is parallel to the stretching direction and located at the intersection of the basal planes of phyllosilicates, forming grain-scale folds and crenulations. This spatial configuration reflects basin scale deformation processes and suggests the existence of a nearly uniaxial stress field during the incipient extensional phases. The integrated approach of magnetic and mineral fabric investigations is a valid tool to detect grain scale and regional deformation pattern in weakly deformed extensional basins, where macroscopic evidence of deformation is not visible.

An integrated structural, anisotropy of magnetic susceptibility (AMS) and paleomagnetic study was carried out on Plio-Pleistocene sedimentary basins in eastern Sicily. These basins belong to three main tectonic domains: the Tyrrhenian hinterland domain, the Catania foredeep domain, and the Hyblean foreland domain. We sampled 329 oriented samples from 25 sites in selected areas from the different tectonic domains. The AMS is typical for weakly deformed sediments, with a magnetic foliation sub-parallel to the bedding plane, and a well-defined magnetic lineation. The orientation of the magnetic lineation is strongly controlled by the main tectonic deformation recorded in the basins. Structural and AMS data define a transition fromNW–SE extension in the Tyrrhenian hinterland domain, to E–Wcompression in the Catania foredeep domain, to E–W extension in the Hyblean foreland domain, respectively. Reliable paleomagnetic results have been obtained in 12 out of 25 sampled sites. Data show that no significant rotations occurred in any of the studied basins at least since the middle Pleistocene. These results allow us to define an upper limit to the large rotations about vertical axes that have been previously found in the Calabria and Sicily regions.

In this paper we present geological and geophysical data which constrain the Tertiary and Quaternary evolution of the Italian region, relevant to the interpretation of the genesis of magmatism in the frame of the geodynamic processes. GPS results show that, at the longitude of Sicily, the African approaches the Eurasian plate at a velocity of about 5 mm/yr in a NW direction. Furthermore, data show that the Adriatic foreland presently moves independently from the African plate. Geodetic and seismic data show that NW-SE oriented extension is the main active tectonic process in the Apennine chain. Relative and absolute motions of the Africa and the Eurasia plates indicate several hundred kilometers of convergence since the early Tertiary, in the central Mediterranean. This convergence has been achieved by northwestward dipping subduction of the African plate. The main present-day geodynamic feature of the Italian region is represented by seismicity on a well defined Benioff zone, which reveals a still active process of subduction from the Ionian foreland below the Calabrian Arc and Tyrrhenian Sea. This slab is the result of a NW directed long running subduction process active since the Tertiary, which consumed the Ligure oceanic basin first, then a small fragment of the Apulian continental lithosphere, and finally most of the present-day Ionian lithosphere, whose subduction is still ongoing. We also suggest that the lateral break-off of the Ionian subducting lithosphere could allow lateral astenospheric flow above the subducted plate either from the Apulian plate and from the Sicily Channell

In this paper, new paleomagnetic and anisotropy of magnetic susceptibility (AMS) data from Miocene continental units of the Cankiri Basin are presented, with the main goal of providing additional constraints on its deformational and rotational history during the Late Cenozoic. AMS data indicate a tectonic origin for the magnetic fabric, suggesting that Upper Miocene units were still involved in the deformation processes. Paleomagnetic data show that tectonic rotations in the Cankiri Basin do not show a symmetrical distribution along the opposite edges of the basin, as expected from the observed Omega-shape. In particular, by combining our data with those already published, we observe that tectonic rotations increase from the southern portion of the basin toward the north and from the central part toward the basin margins. This distribution reasonably matches with a post-Late Miocene reactivation of the Cankiri Basin margin fault systems, possibly related to the activity of the right-lateral North Anatolian strike-slip fault. In this tectonic interpretation, the complex pattern of paleomagnetic rotations appears to be connected with a local block rotation mechanism due to the activity of faults with strike-slip components of motion along the tectonic margins of the Cankiri Basin.