Tyrrhenian Region Research Articles

Tornadoes in the Tyrrhenian regions of the Italian peninsula: The case study of 28 July 2019

On 28 July 2019 an EF2 tornado affected a small rural area in central Italy causing several damages and one casualty. The tornado was spawned by a thunderstorm embedded in a linear convective system that crossed the central Tyrrhenian regions of Italy. The environment was characterized by high values of convective available potential energy (CAPE) and deep layer wind shear (DLS). The severity of this type of events highlights the importance of carrying out multi-scale integrated analysis on tornado phenomena in the area, one of the most affected by these events in the Mediterranean and on which dedicated studies have not yet been carried out so far.Tornadoes in the area are identified in the years 1990–2021, allowing to perform a synoptic/mesoscale analysis of the main patterns associated to these events. The 32-year analysis is carried out using both radiosonde observations and ERA5 reanalysis.The average synoptic configuration is dominated by an upper level trough over the central Mediterranean Sea and by a low surface pressure area over northwestern Italy, with southwesterly upper-level winds over the Tyrrhenian Sea and higher-than-average northwesterly winds entering the western Mediterranean through the gulf of Lion. Moderate mean values of CAPE (about 700 J Kg−1) and DLS (about 15 m s−1) are found, and the linear shape of the hodograph indicates favorable conditions for multicell systems.High-resolution WRF (Weather Research and Forecasting) model simulations of the 28 July 2019 case study correctly reproduced the event and the structure of the storm. Extreme values of the typical instability parameters/indices denote an environment particularly favorable for tornado formation; some sensitivity tests permitted to evaluate the role of several forcing (Sea Surface Temperature, surface fluxes and orography) in the development and the trajectory of the storm.

Genetic and Phenotypic Characteristics of the Salmo trutta Complex in Italy

Salmonid fish have become ecological and research models of study in the field of conservation genetics and genomics. Over the last decade, brown trout have received a high level of interest in research and publications. The term Salmo trutta complex is used to indicate the large number of geographic forms present in the species Salmo trutta. In Europe, the S. trutta complex consists (based on mitochondrial DNA control region analysis) of seven major evolutionary lineages: Atlantic (AT), Mediterranean (ME), Adriatic (AD), Danubian (DA), Marmoratus (MA), Duero (DU) and Tigris (TI). In several nations, the difficulty of identifying some lineages derives from their wide phenotypic and geographic plasticity and the presence of mixed lineages (due to introgressive hybridization with domestic AT populations). In Italy, the S. trutta complex populations living in the Tyrrhenian area and on the main islands (Sicily, Sardinia and Corsica) showed high genetic diversity. Currently, on the Italian Red List, the protected (near threatened) populations are the AD and ME lineages. Recent studies based on traditional (mitochondrial and nuclear markers) and NGS (next-generation sequencing) analyses have clarified some genetic differences between the populations of the Tyrrhenian region, Sicily, Sardinia and Corsica. Native populations in Sardinia belong to the AD lineage, while those living in Corsica are mainly characterized by the AD, MA and ME haplotypes. In Sicily, in the area of the Iblei mountains, an AT lineage (North African) exists. According to some authors, the term Salmo macrostigma should only be used for populations in North Africa. The use of genotyping methods based on mtDNA and nuclear markers and the latest generation sequencing techniques can improve the study of populations and evolutionary lineages in areas where there are overlaps and hybridization phenomena.

Concurrent MORB-type and ultrapotassic volcanism in an extensional basin along the Laurentian Iapetus margin: Tectonomagmatic response to Ordovician arc-continent collision and subduction polarity flip

Arc-continent collision, followed by subduction polarity flip, occurs during closure of oceanic basins and contributes to the growth of continental crust. Such a setting may lead to a highly unusual association of ultrapotassic and mid-ocean ridge basalt (MORB)-type volcanic rocks as documented here from an Ordovician succession of the Scandinavian Caledonides. Interbedded with deep-marine turbidites, pillow basalts evolve from depleted-MORB (εNdt 9.4) to enriched-MORB (εNdt 4.8) stratigraphically upward, reflecting increasingly deeper melting of asthenospheric mantle. Intercalated intermediate to felsic lava and pyroclastic units, dated at ca. 474−469 Ma, are extremely enriched in incompatible trace elements (e.g., Th) and have low εNdt (−8.0 to −6.6) and high Sri (0.7089−0.7175). These are interpreted as ultrapotassic magmas derived from lithospheric mantle domains metasomatized by late Paleoproterozoic to Neoproterozoic crust-derived material (isotopic model ages 1.7−1.3 Ga). Detrital zircon spectra reveal a composite source for the interbedded turbidites, including Archean, Paleo-, to Neoproterozoic, and Cambro-Ordovician elements; clasts of Hølonda Porphyrite provide a link to the Hølonda terrane of Laurentian affinity. The entire volcano-sedimentary succession is interpreted to have formed in a rift basin that opened along the Laurentian margin as a result of slab rollback subsequent to arc-continent collision, ophiolite obduction and subduction polarity flip. The association of MORBs and ultrapotassic rocks is apparently a unique feature along the Caledonian-Appalachian orogen. Near-analogous modern settings include northern Taiwan and the Tyrrhenian region of the Mediterranean, but other examples of strictly concurrent MORB and ultrapotassic volcanism remain to be documented.

Copper to Tuscany - Coals to Newcastle? The dynamics of metalwork exchange in early Italy.

The paper discusses results of an interdisciplinary research project integrating lead isotope, chemical, and archaeological analysis of 20 early metal objects from central Italy. The aim of the research was to develop robust provenance hypotheses for 4th and 3rd millennia BC metals from an important, yet hitherto neglected, metallurgical district in prehistoric Europe, displaying precocious copper mining and smelting, as well as socially significant uses of metals in 'Rinaldone-style' burials. All major (and most minor) ore bodies from Tuscany and neighbouring regions were characterised chemically and isotopically, and 20 Copper Age axe-heads, daggers and halberds were sampled and analysed. The objects were also reassessed archaeologically, paying special attention to find context, typology, and chronology. This multi-pronged approach has allowed us to challenge received wisdom concerning the local character of early metal production and exchange in the region. The research has shown that most objects were likely manufactured in west-central Italy using copper from Southern Tuscany and, quite possibly, the Apuanian Alps. A few objects, however, display isotopic and chemical signatures compatible with the Western Alpine and, in one case, French ore deposits. This shows that the Copper Age communities of west-central Italy participated in superregional exchange networks tying together the middle/upper Tyrrhenian region, the western Alps, and perhaps the French Midi. These networks were largely independent from other metal displacement circuits in operation at the time, which embraced the north-Alpine region and the south-eastern Alps, respectively.

A scenario-based assessment of the tsunami hazard in Palermo, northern Sicily, and the southern Tyrrhenian Sea

Abstract Palermo is a populous city situated on the northern coast of Sicily, bordered by the Tyrrhenian Sea. This central part of the Mediterranean Sea features dramatic bathymetry, numerous subaqueous landslides and is also the epicentre to many subaqueous earthquakes. As such, the region is an area prone to tsunamis. This investigation uses the Cornell Multi-Grid Coupled Tsunami (COMCOT) tsunami modelling package to simulate five near-field landslides, and five near-field earthquakes regarded as worst-case credible scenarios for Palermo. The seismic simulations produced waves on a very small scale, the largest being c. 5 cm at its maximum height, and none of the earthquake-generated tsunami waves produced any measurable inundation. The landslide simulations produced larger waves ranging from 1.9 to 12 m in maximum height, two of which resulted in inundation in areas surrounding the Port of Palermo. Sensitivity analysis identified that fault width and dislocation as well as landslide-specific gravity did have significant influence over maximum wave height, inundation and maximum run-up wave height. There are methodological issues limiting the extent to which this study forms a comprehensive tsunami hazard assessment of Palermo, such as gaps in bathymetric data, computational restrictions and lack of a probabilistic element. These issues are counteracted by the fact that this study does serve as a robust first step in identifying that landslides in the region may produce larger tsunami waves than earthquakes, and that the directionality of mass movement is critical in landslide-driven tsunami propagation in the southern Tyrrhenian region.

The application of use-wear analysis to the study of function of prehistoric Sicilian textile tools

Hitherto, the function of ceramic implements used in textile manufacture was defined mainly through the analysis of their functional parameters (weight and thickness) and tested in experimental spinning or weaving. This paper discusses the application of use-wear analysis to the study of function of prehistoric Sicilian textile tools that could not be unambiguously identified as spindle-whorls or loom-weights based only on their morphological features (weights, dimensions, and/or forms). It presents the results of an experimental approach intended to verify whether the types of wear previously distinguished through macroscopic observation of the artifacts’ surfaces are the result of spinning. The comparison of functional wear obtained from experimental spinning with ceramic replicas of the advanced Early and Middle Bronze Age (c. 1700–1250 BC) artifacts unearthed in the Aeolian Archipelago, lower Tyrrhenian region, with traces preserved on archaeological material allowed the proposition of an alternative interpretation of their function. This study provided, through a process of elimination, an indication of which of these tools were more likely used for weaving, instead of spinning.

Long-distance mobility in the North-Western Mediterranean during the Neolithic transition using high resolution pottery sourcing

The Neolithisation of the North-Western Mediterranean is still an open issue. New data has recently enriched the chronological and cultural archaeological framework, providing more precise absolute dates and revealing a new and more complex process of expansion of farming in Southern Europe.The Mediterranean route of colonization (6000–5600 BCE), is characterized by the so-called Impressed Wares (IW) or Impresso-Cardial Complex (ICC) which demonstrate huge internal diversity in material culture, notably in pottery style and technology. This polythetic imprint of the ICC is intimately linked to dynamics of raw material exploitation (such as obsidian) and interconnections within circulation and exchange networks of goods.Through a comparative and multi-analytical approach to pottery characterization of entire assemblages from two distant sites in the North-Western Mediterranean, each characterized by predominantly local pottery production, we demonstrate long-distance mobility of non-local pottery vessels from the Tyrrhenian regions towards the Languedoc (up to 1000 km) during the Neolithic transition. Our study allows us to highlight this unexpected milestone in the first Neolithic migration in the North-Western Mediterranean.

Clunio boudouresquei sp. n. and Thalassosmittia ballestai sp. n., two Tyrrhenian marine species occurring in Scandola Nature Reserve, West Corsica (Diptera: Chironomidae)

Clunio boudouresquei sp. n. and Thalassosmittia ballestai sp. n. are diagnosed and described based on associated material of male adults, pharate male adults and pupal exuviae recently collected in the marine littoral zone of Scandola Nature Reserve (Cala Litizia, Punta Palazzu, Focolara Bay, West Corsica). While C. boudouresquei sp. n. is described as male and female adults and pupal exuviae, T. ballestai sp. n. is described only as male adult and pupal exuviae. On the basis of some atypical characters found in the male adult and pupal exuviae, both C. boudouresquei sp. n. and T. ballestai sp. n. appear to belong, to a local Tyrrhenian element. Biological cycles of both new species are closely related to alternation between marine and terrestrial ecological conditions, which are strongly reinforced during spring tides of lunar rhythms. Larval stages of both new species are typically marine shore dwellers of the intertidal zone along seacoasts of the Tyrrhenian sub-region, where the biological and ecological quality of marine coastal habitats are being seriously damaged by various anthropogenic activities. In the latter sites, the Lithophyllum byssoides (Lamarck) Foslie pavements (trottoirs, encorbellements) are actually threatened by the massive proliferation of Sea Mussels (Mytilidae), which predominate when changes in water quality and level of pollution become increasingly high. The two new species are considered as pertinent biological indicators of the marine coastal habitats around the Tyrrhenian Region, in particular, those delimited by the mid-littoral large bio-constructions of the red calcified alga L. byssoides, where the larvae of C. boudouresquei sp. n. are exclusively confined. Such threatened species are considered biogeographic Tyrrhenian representatives and indicators of global warming and local climate change in the region, particularly to a rising sea level. Comments on the taxonomic position, ecology and geographical distribution of the new species are given.

Settlement, space organization and land-use of a small Middle Bronze Age community of central Italy. The case study of Gorgo del Ciliegio (Arezzo-Tuscany)

The Middle Bronze Age site of Gorgo del Ciliegio is located in the Afra valley (Upper Tiber basin) in the proximity of strategic trans-Apennine passes connecting the Tyrrhenian regions of Central Italy to the Po plain and the Umbrian-Marches territories. At Gorgo del Ciliegio a Middle Bronze Age small settlement composed of a single house and various kinds of ancillary features was discovered. Through a multi-disciplinary approach it was possible to gather a large amount of information about settlement dynamics implemented by people living at Gorgo del Ciliegio and about the ways in which this community interacted with and took advantage of the surrounding environment/landscape, while adapting the site's economy to natural features.This paper focuses on the evidence provided by material culture, environment and landscape considered as interrelating indicators of social identity and economic strategies. In order to contextualize these issues, broad space was given to the spatial organization and the architectural features as key factors of socio-economic complexity. The authors conclude that Gorgo del Ciliegio was a farm settlement being probably part of a more extensive settlement system, composed of several farms dispersed along the Afra valley. This specific context proved to be particularly suitable for interweaving relations and exchanges with the Adriatic regions, and thus promoting (and being promoted by) the development of an economy mainly based on mobile pastoralism.

Brown trout (Salmo trutta L.) high genetic diversity around the Tyrrhenian Sea as revealed by nuclear and mitochondrial markers

The brown trout (Salmo trutta L.) is widely distributed all around Europe but its natural diversity is threatened by massive stocking with Atlantic domestic strains. Describing the remaining natural genetic diversity and the proportion of domestic hatchery strains in rivers is a prerequisite for smart conservation. The high genetic diversity of brown trout populations around the Tyrrhenian Sea is well known. Use of twelve microsatellites has allowed description of the natural genetic structure of populations and detection of the consequences of stocking. Mitochondrial DNA control region sequences and the LDH-C1* gene enabled placement of each population into one of the six mitochondrial and two allozymic known evolutionary lineages. The Corsican populations showed low intra-population genetic diversity but an exceptionally high level of inter-population differentiation. More southern Tyrrhenian regions exhibited opposite pattern of diversity, partly due to the Atlantic domestic introgression. Globally, the natural structure outlines two north–south clines: high inter-population differentiation and predominance of the Adriatic lineage in the north, but lower inter-population differentiation and the presence of the natural Atlantic lineage in the south. In addition, the Tyrrhenian region is the contact zone between the widespread Adriatic lineage and a local natural Atlantic lineage probably coming from North Africa through the Strait of Gibraltar.

Between al-Andalus and Genoa: The “Embriaci Tower” Lustreware

ABSTRACTThis article examines a set of lustreware pottery discovered in the fill of the tower belonging to the Genoese family, the Embriaci. The finds are datable to the mid-thirteenth century, characterised by decorative patterns which are atypical in lustreware production in al-Andalus, though some comparisons can be drawn with the decorative patterns of the “vasos de la Alhambra” and the pottery known as “nazarí primitive”. The context of the discovery in Genoa will briefly be outlined, including the story of the family settlement (Part 1), the stratigraphic sequence (Part 2), and the stylistic connections to other pottery characterising it (Part 3). The formal and decorative elements characterising the lustreware pottery found in the Embriaci Tower will then be examined and compared (Part 4) with finds from the Upper Tyrrhenian region (Provence, Savona, Pisa). Part 5 will suggest that the finds are a specific type of decorated lustreware produced in the thirteenth century in al-Andalus (Murcia, Málaga and Almería). The concluding part (Part 6) will investigate the meaning of the presence of the set of imported ceramics in the “curia” of the Embriaci family in Genoa.This type of pottery has only been discovered hitherto in excavation finds and architectural contexts (the so called “bacini”) in Italy and France. The identification of decorative and formal elements characterising this “group” of pottery will allow the identification of examples of this production outside of Italy and France. The publication of the findings will provide new data to develop an archaeological overview of commercial contacts between al-Andalus and the Tyrrhenian area (Provence, Liguria, Tuscany) during the thirteenth century.

Wine Production and Exchange and the Value of Wine Consumption in Sixth-century BC Etruria

This paper attempts to bridge the gulf between two often separate research agendas in Archaic period Etruria, one concerned with the archaeology of wine and agricultural production and redistribution, the other with figured representations of drinking and the associated symbolic visual language. It does so by examining the relationship between changing processes of production, consumption and exchange and the symbolism of drinking in the visual and material culture of sixth-century bc Tyrrhenian Etruria. In this analysis, I maintain that changing modes of agricultural production and distribution had an impact on such symbolism in elite funerary and domestic contexts, with key evidence also coming from sanctuaries. In particular, it is argued that during the seventh century bc, the visual language related to wine drinking alludes to experiences of bodily otherness; this is indicated by the symbolic correlation between accessibility to wine, the dangers of maritime travel and death. From the sixth century bc, we can trace a shift towards a visual language that centred on cultural difference or otherness: this is noticeable in the introduction of Dionysiac imagery and new mythological narratives of cross-cultural encounters, as well as in a new emphasis on codified drinking and culturally differentiated drinking vessels. This shift is more or less contemporary with other changes, namely the production and distribution of agricultural surplus in the Tyrrhenian region and beyond, and shifting values of objects in that exchange.

Present-day kinematics and deformation processes in the southern Tyrrhenian region: new insights on the northern Sicily extensional belt

We performed a new analysis of updated and accurate sets of seismic and GNSS data relative to the southern Tyrrhenian region. Detailed velocity field and crustal strain distribution coming from integration of episodic and continuous measurements at more than 160 geodetic sites (spanning the 1994-2015 period) have been evaluated together with the spatial distribution of recent seismicity and an updated catalogue of waveform inversion fault-plane solutions relative to the period 1976-2014. In agreement with previous investigations, we have found that the kinematics of the study area is quite homogeneous except for the north-eastern corner of Sicily which moves almost coherently with southern Calabria in response to the SE-ward rollback of the Ionian slab. The rest of the study region shows a NNW-trending velocity field in agreement with the direction of the Nubia-Eurasia convergence and it is mainly interested by a major compressive domain. NNW-oriented compression is particularly highlighted by seismic data along the E-W trending seismic belt located in the southern Tyrrhenian Sea. In the framework of such compressive regime, the E-W trending extensional domain of northern Sicily is also clearly depicted both by seismic and geodetic data. The cause of this extensional domain framed inside a mainly compressive one represents an open question in the recent scientific debate. Comparisons between our results and literature information on regional geology and crustal structure led us to investigate whether the extension could occur as local response to the thrusting dynamics of the southern Tyrrhenian belt, favoured by the presence of pre-existing weakness zones. We then propose a first attempt to evaluate such a possible causal relationship by means of Finite Element Method (FEM) and Coulomb Stress Change (CSC) modelling. In particular, we adopted a FEM approach to investigate the deformation pattern produced by thrust faulting of southern Tyrrhenian belt, along a 2D profile crossing both the compressive belt and the extensional one in northern Sicily. We also estimated the CSC due to the thrust faulting on normal receiving faults fairly reproducing pre-existing structures of northern Sicily. Modelling results indicate that the thrust faulting activity along the Southern Tyrrhenian compressive margin could be effective in promoting extensional processes in northern Sicily. We have so shown that the local response to thrust faulting activity may concur, even in combination with other processes, to generate the crustal stretching of northern Sicily.

Submarine canyons along the upper Sardinian slope (Central Western Mediterranean) as repositories for derelict fishing gears

By means of ROV surveys, we assessed the quantity, composition and bathymetric distribution of marine litter in 17 sites along the Sardinian continental margin (Central Western Mediterranean) at depths ranging from 100 to 480m. None of the investigated sites was litter free, but the mean density of litter (0.0175±0.0022itemsm−2) was lower than that reported from other Tyrrhenian regions. The difference in the total litter density among sites was negligible, but the density of derelict fishing gear (DFG) items (most of which ascribable to small scale fishery) in submarine canyons was higher in submarine canyons than in other habitats. Our result suggest that submarine canyons (known to be highly vulnerable ecosystems) act as major repositories of DFGs, and, therefore, we anticipate the need of specific measures aimed at minimizing the loss and abandonment of DFGs in submarine canyons.

Coordinated Decisions and Unbalanced Power. How Latin Cities Shaped Their Terrestrial Transportation Network

The period between the beginning of the Early Iron Age and the end of the Archaic Period is a time of changes and developments in the Italian Peninsula, which led to the creation of regional ethnic and political groups and to the formation of the first city-states in Western Europe. In the present study, we focus on the evolution of terrestrial route network in the Tyrrhenian region of Latium vetus as it has been hypothesised by scholars from the archaeological evidence. Our main goal is to investigate the mechanisms linking decision making processes and the structure of transportation networks. We first attempted to replicate some of its features applying three models previously elaborated for the neighboring region of Southern Etruria. Since it was not possible to attain entirely satisfactory results, we modified the model that performed better in the Etruscan region by including a tunable amount of rich-get-richer bias which improved considerably its performance. Our results suggest that coordinated decision making with a slightly unbalanced power was responsible for the peculiar characteristics of the route network topology of Latium vetus. Moreover, the mechanism implemented by this model implies that places located at favourable positions can build on their initial advantage and get more and more powerful. This fits very well with the picture elaborated by different scholars on the nature of power balance and dynamics in this region.

Geopalaeontological setting, chronology and palaeoenvironmental evolution of the Baccinello-Cinigiano Basin continental successions (Late Miocene, Italy)

The Latest Miocene succession of the Baccinello-Cinigiano Basin in southern Tuscany (Italy) recorded a faunal turnover documenting the extinction of an older, insular, endemic faunal complex characterised by the extinct ape Oreopithecus bambolii and the setting of a new, continental, European faunal complex including the colobine monkey Mesopithecus. A similar turnover pattern (Late Miocene ape/Latest Miocene Cercopithecidae) is generally observed in Late Miocene continental successions of Eurasia, from Spain to central Europe, Southwest Europe, the near East, and Southwest Asia. Abundant literature reports that the Late Miocene Eurasian hominoid primate distribution closely tracks the climatic/environmental changes occurring during the 12–9Ma interval, until their extinction in western Europe. In the primate record, the dispersion of Cercopithecidae and the contraction of hominids is interpreted as an event depicting a pattern of “continentalisation” in the Old World. The sedimentary succession of the Baccinello-Cinigiano basin, one of the longest continuous vertebrate-bearing continental successions in the Neogene Italian record, contributes to the debate on this hypothesis. This paper provides an overview of the main characteristics of the sedimentary succession, the chronological constraints (biochronology, radiometric datings, magnetostratigraphy), and the palaeoenvironmental evolution as derived from palaeobiological approaches and from the study of stable carbon and oxygen isotope contents along the entire sedimentary succession. The 2myr geological history of the Baccinello Cinigiano Basin, which documents the evolutionary history of Oreopithecus and associated faunas, does not have a direct relation with the event of the Messinian Salinity Crisis. The evolutionary history of Baccinello-Cinigiano Basin and its palaeontological record have been mainly driven by the regional tectonism and palaeogeographic changes that affected the northern Tyrrhenian regions in Late Miocene (Latest Tortonian–Messinian) times.

The Miocene of Pianosa Island: key to understanding the opening of the Northern Tyrrhenian back-arc basin (Central Mediterranean)

The only place where Neogene–Quaternary rocks crop out for the entire Tuscan Archipelago in the Northern Tyrrhenian Sea is the island of Pianosa. In particular, the Miocene deposits record the depositional and tectonic evolution of the Northern Tyrrhenian region during this time period. These deposits are subdivided into two successions separated by a low-angle unconformity. The older, middle Burdigalian succession represents a calciturbidite shallow marine system, whereas the younger late Tortonian–early Messinian succession comprises a continental alluvial system that evolves upwards into a lagoonal–marginal marine environment. Here we present sedimentological, palaeontological and petrographical data that support a new stratigraphic and palaeogeographical framework for reconstructing the opening of the Northern Tyrrhenian back-arc basin. The early Miocene succession records a pre-rift marine depositional phase followed by a late Burdigalian–Langhian erosional phase. This was followed by a period of synrift continental-marginal deposition, as recorded by the late Miocene succession, terminated by an important phase of uplift, probably induced by the start of magmatic activity in the Tuscan Archipelago area.

Early-stage rifting of the Southern Tyrrhenian region: The Calabria–Sardinia breakup

The Southern Tyrrhenian Sea is an extensional basins linked to the Neogene evolution of the Calabria subduction zone located in the western Mediterranean realm where controversial kinematic and geodynamical models have been proposed. Our study provides a key to unravel timing and mode of extension of the upper plate and the breakup of Calabria from Sardinia. By combining original stratigraphic analysis of wells and seismic profiles off Calabria with a stratigraphic correlation to onshore outcrops, we re-assess the tectonic evolution that controlled the sedimentation and basement deformation of the Southern Tyrrhenian basin during Serravallian–Tortonian times. We document the tectono-stratigraphic evolution of adjacent extensional basins characterized by 3rd order depositional sequences (Ser1, Tor1 and Tor2) and different modes of extension, subsidence and opposite dipping faults. Episodic basin development is recorded by a coarsening-up and fining-up trend of the sedimentary succession and by tectonically enhanced unconformities that reflect three episodes of fault activity. We reconstruct Serravallian–Tortonian paleogeographic maps and propose a block faulting model for the evolution of the Sardinia–Calabria area. Sardinia was disconnected from Calabria through N–S normal faults forming Tyrrhenian extensional basins that formed contemporaneously to the E–W opening of the Algerian basin. Unlike published Serravallian–Tortonian reconstructions of the western Mediterranean realm, our results support a geodynamic model characterized by rapid trench retreat, trench-normal extension in the entire overriding plate and very weak coupling between plates.

Cork oak woodlands in the north Tyrrhenian area (Italy): distribution and plant species diversity of a relict forest ecosystem

Italian north Tyrrhenian regions harbour pure or nearly pure cork oak woodlands towards the NE limit of the species range and the highest proportion of the habitat on mainland Italy, but their distribution, biodiversity and conservation status are still poorly known. Focusing on the key region of Tuscany, we analysed distribution and plant species richness of these forests based on literature and original field data. The habitat covers about 5.730 ha and is strongly fragmented for natural and non-natural reasons, underscoring its relict character. Out of the 420 plant taxa recorded, 19 were listed in IUCN categories at the national or regional level. Taxonomic singularity was especially high at the genus rank. Three neighbouring areas with different soil conditions and forest structure were compared based on field surveys, sample plots and linear transects from dense stands to shrub and herbaceous communities of small openings. The Versegge site showed the highest species richness at the area-scale and the mean diversity at the plot scale, representing a key biotope for the conservation of the habitat. However, the geographic–floristic covariation between the three sites suggested that a network of small areas would be more effective than a single, large area to protect the most significant components of the local cork oak flora. The Lattaia and Terzo areas may play an important role as corridor sites between the four SCIs of the Rete Natura 2000 network including cork oak communities on the Tuscan mainland. Species richness was higher in the stands with lower cork oak basal area, and there was a significant increase in species number along transects reaching openings caused by traditional human activities. A minor anthropic disturbance of traditional type may help to preserve the fine-scale habitat heterogeneity and the biodiversity of the whole ecosystem.

Tectono-metamorphic evolution of the siliciclastic units in the Middle Tuscan Range (inner Northern Apennines): Mg–carpholite bearing quartz veins related to syn-metamorphic syn-orogenic foliation

This paper accounts for a new finding of High Pressure–Low Temperature (HP-LT) metamorphism documented in continental-derived rocks exposed in the central part of the Middle Tuscan Range, representing the easternmost location, in the Tyrrhenian Region, where blueschist facies metamorphism has been documented. It describes the development mechanism of Mg–carpholite bearing quartz veins in the framework of the deformational events described for the inner Northern Apennines. The HP-LT peak metamorphism can be estimated in P≥1.1GPa and T=370°–420°C as supported by the mineralogical assemblage consisting of quartz–muscovite–chloritoid–pyrophylite–hematite±chlorite±paragonite±Ti-oxides, documented in the aluminous metasediments (pelites and quartzose sandstones) of the Triassic Verrucano succession. This paragenesis defines the S1 schistosity, an axial planar tectonic foliation associated to map- and mesoscale isoclinals folds (F1); S1 schistosity is a composite foliation resulted from a non-coaxial progressive deformation associated to the DE1 collisional event (Late Oligocene–Early Miocene). Mg–carpholite bearing quartz veins developed as tension gashes in en-échelon arrays within brittle/ductile shear zones. The development of quartz veins was guaranteed by the high volumes of Si-rich fluids produced by the dynamic recrystallization process on the siliciclastic rocks.