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The study was performed in central-northern Anatolia (from Ankara to Amasya) to investigate the relationships of the Sakarya Zone units and the Izmir–Ankara–Erzincan suture (IAES) melange. It reveals that all the Sakarya Zone units are metamorphic and three main tectonostratigraphic units have been distinguished for the first time: the BAA (metasiliciclastic rocks capped by metacarbonates and varicoloured phyllite), the BKC (poly-metamorphic garnet-bearing micaschist and metabasite with a well-preserved relict HP–LT amphibole in a low-amphibolitic to greenschist-facies framework) and the AMC (meta-arkose passing vertically to carbonate–phyllitic alternations and, then, to a thick succession of prevailing acidic to intermediate–basic metavolcanites and volcanic-rich metasediments). The BAA and AMC, whose metamorphic frameworks are of Cimmerian age, underlie the Mesozoic carbonate cover sequences (e.g. t2-3, j3–k1) that often show tectonic detachments and slicing. The piling up of the BAA above the HP–LT BKC can be correlated to the tectonic superposition of two similar units (i.e. the Cimmerian Çangaldağ Complex and the Alpine Middle–Upper Cretaceous Domuzdağ Complex, respectively) defined by previous authors in other sectors of the Central Pontides front. The ophiolitic melange generally underlies the Sakarya Zone, but locally (e.g. SE of Amasya) tectonically rests above the latter, probably owing to back-thrusting that occurred during the Tertiary syn-collisional shortenings and the later strike-slip tectonics. We hypothesize that, also in these areas, the Sakarya Zone–IAES consists of a complex tectonic stack of different units, belonging to different palaeogeographic domains and orogenic events (Cimmerian versus Alpine orogenies), but originated within a single long-lived (since Late Triassic to Paleocene/Eocene times), prograding subduction–accretion system in front of the Laurasian continent.

The Variscan orogeny occurred as a result of the Late Devonian to Late Carboniferous collision and accretion of Gondwana-derived microcontinents and continental masses with those of Laurussia. The irregular boundaries of the colliding continents caused isochronous transpressional and transtensional tectonics, accompanied by a complex pattern of intracontinental shear zones at the scale of the southern European Variscides. These shear zones and their configuration controlled the subsequent evolution of Permian to Middle Triassic paleogeography. The geographic distribution, from Morocco to the Eastern Alps, of the Late Carboniferous–Permian up to Triassic basins, most of which are considered as pull-apart basins, was related with the development of the Late Palaeozoic intracontinental shear network. Our analysis of the stratigraphic, tectonic and volcanic features of the Late Carboniferous/Permian continental basins across the Laurussia/Gondwana boundary reveals the role of the East Variscan Shear Zone during this time as a precursory lineament for the development of the Permian to Triassic rifting of Pangaea and the following opening of oceanic basins (e.g., the Neothetyan Ocean).

The present study is aimed at providing a brief overview of the Italian acidic waters based on literature and unpublished data. Acidic waters in Italy, as elsewhere, are relatively common and associated with extremely variable geological settings. Owing to their peculiar features, these waters may seriously affect the environment and the ecosystems. Along the Apennine belt, the western and inner sectors of the Italian peninsula record an anomalous geothermal gradient, mostly overlapping with the Neogene-to-present magmatism, that explains the presence of a huge amount of CO2(H2S)-rich gas and thermal water discharges, geothermal fields (e.g. Larderello and Mt. Amiata) and ore deposits (e.g. Fe- and polymetallic sulfides, e.g. Elba Island and Colline Metallifere). Acidic waters (pH ≤5) from volcanic and geothermal areas show outlet temperatures and Total Dissolved Solids (TDS) from 10 to 96°C and

The Mt. Amiata mining district (Southern Tuscany, Italy) is a world class Hg district, with a cumulate production of more than 100,000 tonnes of Hg, mostly occurring between 1870 and 1980. The Hg mineralization at Mt. Amiata is younger than 0.3 Ma, and is directly related to shallow hydrothermal systems similar to present day geothermal fields of the region. There is likely a continuum of Hg deposition to present day, because Hg emission from geothermal power plants is on-going. In this sense, the Mt. Amiata deposits present some analogies with "hot-spring type" deposits of western USA, although an ore deposit model for the district has not been established. Specifically, the source of Hg remains highly speculative. The mineralizing hydrothermal fluids are of low temperature, and of essentially meteoric origin. Recent results by our research group indicate that, 30 years after mine closure, the environmental effects of Hg contamination related to mining are still recorded by the ecosystem, namely on waterways of the Paglia and Tiber River basins. In particular, the close spatial connection between the town of Abbadia San Salvatore, the Hg mine within its immediate neighborhood, and the drainage catchment of the Paglia River has an influence also on Hg speciation, transported mainly in the particulate form by the river system. The extent of Hg contamination has been identified at least 100 km from Abbadia San Salvatore along the Paglia-Tiber River system. Estimated annual Hg mass loads transported by the Paglia River to the Tiber River were about 11 kg yr-1. However, there is evidence that flood events may enhance Hg mobilization in the Paglia River basin, increasing Hg concentrations in stream sediment. The high methyl-Hg/Hg ratio in water in this area is an additional factor of great concern due to the potential harmful effects on human and wildlife health. Results of our studies indicate that the Mt. Amiata region is at present a source of Hg of remarkable environmental concern at the local, regional (Tiber River), and Mediterranean scales. Ongoing studies are aimed to a more detailed quantification of the Hg mass load input to the Mediterranean Sea, and to unravel the processs concerning Hg transport and fluid dynamics.

The Scaglia Toscana Formation (Scisti Policromi Auctt.) is one of the most investigated formations of the Tuscan Nappe. The formation is widely exposed in the Chianti Mounts and despite the number of studies in this area, some aspects remain poorly known and debated. In this paper new litho-and bio-stratigraphic data from eight key-sections distributed over the entire area are provided and discussed in order to clarify the stratigraphic relationships among different lithostratigraphic members, as well as the depositional ages of each member. The formation was deposited in the Cretaceous-Oligocene time interval and it can be subdivided into five lithostratigraphic members: i) the "Argilliti di Brolio" (wine-red shales with sporadic siliceous calcilutites and rare interbedded cherts); ii) the "Marne del Sugame" (red and pink marls, calcareous marls and marly limestones with interbedded calcarenitic beds and ruditic lens-shaped bodies including calcareous-siliceous clasts); iii) the "Argilliti di Cintoia" (grey-green to black shales, locally with manganese-rich siliceous calcilutites and cherts); iv) the "Calcareniti di Montegrossi" (thin beds of calcilutites and calcarenites with varicoloured shaly-marly interbeds); and v) the "Argilliti e Calcareniti di Dudda" (alternating thin beds of calcilutites and calcarenites with varicoloured shaly-marly interbeds). These members were deposited in a marine environment and have been interpreted as deposited in a turbiditic system, in which shaly and calcareous turbiditic members have been attributed to a basin plain below the CCD, whereas the marls and marly limestones of the Marne del Sugame Member were deposited in a slope/ramp environment above or close to the CCD. Furthermore, the combination of these new data with structural informations coming from the literature allowed a better paleogeographic reconstruction of the paleobasin. In order to better explain these data, the paper is accompanied by two geological maps realized in the past but never distributed. The two geological maps, at the scale of 1:25,000, cover the whole area from the Cintoia (south of Florence) to the San Gusmè (north of Siena) villages.

CNR-IGG, Section of Florence, Via G. La Pira, 4, 50121 Florence, ItalyIn the Inzecca-Ghisoni area (southern Alpine Corsica), a complexassemblage of vertically juxtaposed tectonic units, affected byAlpine deformations and metamorphism, crops out. Among them, there are some tectonic units (Parautochthonous Units, i. e.parautochtone of previous studies), that represent fragments of the continental Corse basement (Palaeozoic granitoids andassociated volcanic and metamorphic pre-Carboniferous rocks) and of its Mesozoic to Tertiary sedimentary cover, that aretectonically sliced between the allochthonous Ligurian-Piedmontese Units (Schistes Lustre´s) and the autochthonous basement(Variscan Corsica). The reconstructed polyphase deformation and metamorphic evolution of such units and the finding of high-pressure/low-temperature mineral assemblages in the continental-derived tectonic slices, points to the involvement of the south-eastern border of the European basement of Corsica inthe tectonic processes linked to the Alpine subduction. Copyright #2009John Wiley & Sons, Ltd.

Brunelleschi conceived the Santa Maria del Fiore (Florence Cathedral) Cupola as a self-sustaining structure. To that purpose, he introducd new techniques and a selected use of building materials. The archives of the Opera del Duomo show that particular materials were chosen for specific uses, and in many instances the precise quarry where the stones had to come from was specified. In the Brunelleschi's idea, the chains containing the outward thrusts of the Cupola involved a high structural relevance. These elements are made of a specific type of Pietra Serena , the ornamental stone derived from the excavation of the best-graded beds of Macigno sandstone. Brunelleschi selected some specific layers, outcropping at the “ Trassinaia ” quarry, peculiar for their mechanical strength. Though the Trassinaia quarry is frequently quoted in the Opera del Duomo documentation, its exact location remained uncertain so far. Detailed analysis of historical and recent cartography, together with landscape, geological and archeo-mining investigations, have now allowed to confidently identify this site in an ancient, abandoned quarry site settled on the right-side of a stream, unnamed at present but originally denominated “ Trassinaia creek ”. This discovery opens, therefore, new perspectives for comparative studies of compositional and mechanical characteristics of correlative stones on the Cupola and at quarry site.

The Orcia River basin lies north of the Mt. Amiata mining district and may receive potentially harmful/toxic elements such as mercury (Hg) and arsenic (As) therefrom. The Orcia River eventually flows to the Ombrone River, which in turn flows to the Tyrrhenian Sea. The analysis of stream sediments collected in the Orcia River and its main tributaries, as well as in the Ombrone River, indicates moderate concentrations of both Hg and As (median values, Hg 118 μg/kg and As 5.25 mg/kg), rarely exceeding Italian environmental quality standards. Exceptionally high values for both elements are observed only in close proximity to the former Pietrineri Hg mine (Hg 195 mg/kg and As 35 mg/kg). Travertine and unconsolidated deposits associated with thermal springs in the area generally exhibit low Hg concentrations (4–320 μg/kg), with a significant exception of 23 mg/kg at Bagni San Filippo. Arsenic concentration in the same deposits is more variable with a peak level of 358 mg/kg. Surface waters collected at the same sites as stream sediments show Hg and As concentrations below the Italian mandatory limits for drinking waters (1 μg/L for Hg and 10 μg/L for As). Likewise, in thermal springs, Hg concentrations are low, whereas As concentrations are relatively high (up to 23.4 μg/L), which is in agreement with previous studies. At present, the input of toxic elements from the mining district into the Orcia and Ombrone watersheds is lower than inputs documented in the Paglia and Tiber catchments south of Mt. Amiata and does not pose an immediate environmental threat. However, the possible remobilization of Hg-contaminated sediments during flash flood events cannot be dismissed.

In December 1998, during excavation for the construction of a new building near San Rossore railway station in Pisa, the remains of ancient ships were discovered. These findings have been dated (radiocarbon) to between the end of the 10th century BC and the fifth century AD (Belluomini et al. 2002). Several transport amphorae belonging to the Hellenistic ship, samples of rocks (stone ballast) belonging to ships B, D and the Hellenistic ship, and stowage materials belonging only to ship B have been analysed. The mineralogical and petrographic data of the investigated samples provided information on the possible provenance of the raw materials utilized in the manufacture of the ceramic amphorae, as well as on the provenance of the rock materials found in the ships as ballast and stowage. The compositional data (obtained through XRD, XRF, OM and EPMA) and their statistical analyses suggest that the provenance of the Dressel amphorae belonging to the Hellenistic ship was the Middle Tyrrhenian coast of Italy, and more precisely the area between Tarquinia and Naples, according to the numerous kilns and wine production sites found in this area. The provenance of the volcanic rocks was from southern Tuscany, northern Latium and possibly the Pontine Islands, whereas the intrusive rock possibly comes from the Calabrian-Tyrrhenian coast and/or the Peloritani area. The impure limestones and the dolostone come from southern Tuscany and the Latium coast; the semi-metamorphic rocks could come from the coast of southern Tuscany, the Tuscan Archipelago or possibly also from the Ligurian coast; only the sample of mylonitized granitoid possibly comes from either the Calabria-Peloritani arc or the Tuscan Archipelago. The stowage materials, consisting of lapilli and scoria of a pyroclastic nature, are sourced from the Neapolitan area. These data might shed some light on the centres of production of the amphorae and of the trading routes followed by the ships, according to the ports of call.

The results are presented for the investigations into the geological estimate of Macigno formation representing an Oligocene-Miocene turbiditic sequence of the Northern Apennines, from the coarse-graded beds of which the “Pietra Serena” quarry stone was mined. It is shown that the sedimentological features, the physico-mechanical properties, and the mineralogical composition of rocks govern the distinctions in the operating performances.

Borgia et al. (2014) illustrated an active volcanic spreading model for the Amiata volcanic area (southern Tuscany, Italy). Although, at first glance, the model may appear appealing, this is not fully supported by the available data and the paper does not take into account their discussion. Accordingly, the supposed negative consequences of the Borgia et al. (2014) model on both contamination of shallow water and geothermal exploitation can likely be regarded as speculative.

The Apennine Range is a young convergent orogen that formed over a retreating subduction zone. Syn-orogenic metamorphic rocks are exposed in the mid-Tuscan ridge, Tuscan coast and Tuscan Archipelago and provide information about processes of continental subduction and exhumation associated with accretion and retreat. Apatite and zircon fission-track analyses were applied to some of these syn-orogenic metamorphic rocks. The new low-temperature thermochrono-logical data helped to constrain the timing of the metamorphic peak and the age and modality of exhumation of these rocks that were structurally buried at 20 to 40 km depth during the main tectonogenic phase of the Northern Appenine belt. In the Giglio and Elba islands and in the Monti dell'Uccellina, along the coast, minimum ages of partially reset zircon samples yielded a first time constraint on the Late-Oligocene age of the metamorphic peak. The ca. 27Ma obtained at the Monti dell'Uccellina is coeval to that found in the Alpi Apuane (located at the northern termination of the mid-Tuscan ridge). The data from the Tuscan Archipelago point to a slightly older age. In the Monti Pisani, south of the Alpi Apuane, and in the Argentario Promontary along the coast, south of the Monti dell'Uccellina, completely reset zircon samples, but composed by different populations, were behaving as multiple thermochronometers and confirm the already proposed isothermal nature of the exhumation occurred after the metamorphic peak. Zircon P1 peak indicated that at 13-10Ma rocks were already at shallow crustal levels (

A comparison of the petro-tectonic features recorded in the Variscan Massifs scattered throughout the Alps, the Corsica-Sardinia-Maures-Tanneron Massif, the Calabria-Peloritani Arc, and the Northern Apennines, has allowed us to propose that they belonged to the same geodynamic realm until Late Carboniferous time. In the interval 330-300 Ma, the development of a regional dextral strike-slip shear zone, the East Variscan Shear Zone (EVSZ), affected all the massifs, leading to their spatial separation. The EVSZ developed, together with numerous regional shear zones, under a transpressional tectonic regime deriving from the Late Carboniferous collision between Gondwana, peri-Gondwana microcontinents (Armorica and Avalonia), and Laurussia plates. The EVSZ evidently played a key role in the evolution of the subsequent Alpine and Apenninic cycles, acting as a pre-existing tectonic barrier. Our proposed geodynamic reconstruction does not reflect the acquisition of new data, but is based on the analysis and review of the recent geological literature.

In order to add new data to the knowledge of the paleogeography of Southern Tuscany and the Tuscan shelf, a multidisciplinary study on the petrology and distribution of magmatic clasts of the widely exposed Messinian, Pliocene, and Quaternary sediments in Southern Tuscany was carried out. The magmatic clasts consist of porphyric aplites and subordinate granite porphyries, which derive from eroded subvolcanic acidic bodies. The porphyric aplite clasts were analyzed in detail to define their textural, petrographic, and chemical (major and trace elements, Sr and Nd isotopic composition) features. The porphyric aplite clasts show strong affinities with the 8.4–7.9 Ma old Capo Bianco aplite, whereas the granite porphyry clasts have affinities with the Portoferraio porphyry (ca. 8 Ma) which intruded the Cretaceous and Paleogene Flysch Units and the Ophiolitic Unit in central-western Elba Island (Northern Tyrrhenian Sea). The present outcrops of the Capo Bianco aplite in central Elba Island cannot be considered as the source rock for the Late Messinian gravels, because at that time such Capo Bianco aplite (located at the lower portion of the laccolitic stack) was there buried at several kilometers depth. However, other Capo Bianco-like aplitic bodies outcropped during the latest Miocene in the host rocks above and also around the 6.8 Ma M. Capanne Pluton in the western Elba areas. The exposure of such bodies was made possible by the activation of the central Elba detachment fault (=CEF), due to the uplift of the M. Capanne pluton. This uplift displaced a significant portion of the cover (including the upper portion of the laccolithic stack) of the granitoid body at about 6, 7 Ma, thus allowing the erosion of the lower part of the laccolith complex made up of the Capo Bianco aplite and of the Portoferraio porphyry and leaving still buried the M. Capanne pluton. The paleogeographic picture of Southern Tuscany arising from the collected evidences is the following: during Late Messinian, the clasts were dispersed by a SSW/NNE-trending complex fluvial system in the Colline Metallifere area. The Early Pliocene extensional tectonics cut off the detrital inputs from the Messinian source areas, because of the onset of the Piombino Channel and of the Campiglia–Gavorrano Ridge. During the Pliocene, the clasts were cannibalized from the previous sedimentary units and reached the easternmost areas due the eastward progressive uplift of the Colline Metallifere, likely connected with the coeval magmatic intrusions. Finally, the Quaternary regional uplift allowed a drainage reversal and a backward displacement of the aplitic clasts toward the Tyrrhenian coast. These data point to a rapidly evolving drainage pattern in Southern Tuscany during the considered time interval, which was mostly driven by the intrusion and uplift of the Messinian to Quaternary plutons. The morpho-tectonic evolution is well framed also within the models since long accepted for the Northern Apennine geodynamics, characterized by an overall eastward shift of the orogenic front.

Several small crater-like structures occur in Gilf Kebir region (SW Egypt). It has been previously suggested that they could be the result of meteoritic impacts. Here we outline the results of our geological and geophysical survey in the area. The proposed impact origin for these structures is not supported by our observations and analyses, and we suggest an alternative interpretation. The crater-like structures in Gilf Kebir area are likely related to endogenic processes typical of hydrothermal vent complexes in volcanic areas which may reflect the emplacement of subvolcanic intrusives.

We have examined the data of 600 geothermal wells and re-interpreted approximately 500 km seismic profiles through the field of Larderello, Italy. We conclude that the two main seismic reflectors present below the geothermal area host two different fluids: (1) superheated steam in the upper H-horizon (reached by drillholes) and (2) supercritical fluid in the deeper K-horizon (reached by few unproductive or damaged wells). The superheated steam has the physical and chemical connotation of the geothermal fluid exploited so far at Larderello, whereas the supercritical fluid represents a potential unconventional deep-seated resource still to be assessed. The high temperatures existing in correspondence of the K-horizon suggest that the silica-rich rocks are close to a plastic state and the fluids should remain confined in a medium sealed to the confining rocks, unless occasional fluid overpressure and abrupt high strain rates occur.

Correlations of the geological elements between different segments of the Variscan Belt in southern Europe (Maures Massif, Corsica-Sardinia Block, Northern Apennines) allow to define a common structural-metamorphic evolution from Early Carboniferous syn-collisional event to the Late Carboniferous-Early Permian, extensional shearing events. In particular, the composite extensional tectonism in the Maures Massif (e.g. the Grimaud Fault) and Sardinia (e.g. the Posada-Asinara Line) consists of two shearing events: a ductile event in the amphibolite facies and and a following ductile (greenschist facies)/brittle and brittle event. During the latter event, syn-tectonic magmatism took place. The correlation of the pre-Alpine successions of the Northern Apennines with ones of the Central and NE Sardinia suggests a possible continuation of the Posada Valley Zone and the Posada-Asinara Line within the Tuscan segment of the Variscan belt. Also on the basis of paleogeographic data, we suggest that, during the Carboniferous-Permian times, the Maures Massif, Corsica-Sardinia block and the Tuscan part of Adria (Northern Apennines) were likely adjacent in the southern part of the Variscan Belt. Journal of the Virtual Explorer, 2005 Volume 19

The upper part of the crystalline basement of the Northern Apennines is made up of a complex pile of tectonic wedges derived from Alpine low-grade metamorphic units (T= temperature = 300°–450°C; P= pressure = 3–4 Kbar), Paleozoic (?Late Cambrian-Permian) to Tertiary in age. The Paleozoic rocks also show evidence of pre-Alpine deformation (e.g. Hercynian schistosity relics and folding).

Randomly dispersed erratic clasts are found within the pelagic marly-shaly sequences of the Oligocene Scisti Varicolori Formation (Cervarola-Falterona unit of the Tuscan domain). These clasts are centimeters to decimeters in size and subrounded to well rounded; their shape suggests an origin in a fluvial and partly littoral environment. The clasts are composed of low- to medium-grade metamorphic rocks, andesitic volcanic rocks, and Late Jurassic–Early Cretaceous pelagic limestones. The source area of the crystalline material is interpreted to be the central-western sector of the Alpine chain or the Corsica-Sardinia area. In addition, the peculiar surfaces of these clasts, as well as their isolated occurrence in the pelagic shales of the Scisti Varicolori, suggest an uncommon depositional mechanism, such as redeposited gastroliths of large marine Vertebrata.

Geological, geophysical and petrologic data point to the presence of a granitic body below the geothermal region of Mt Amiata (central Italy). A broad area of about 900–1300 km 2 centered on Amiata volcano shows a regional uplift of the Pliocene beds to 950 m a.s.l. The uplift began during the lower Pliocene, with a regression of the Pliocene sea from an uplifted area centered in the volcano zone. The temperature distribution below the Piancastagnaio field shows an updoming of the isotherms, forming a thermal high, probably present since the earliest stages of interaction between geothermal fluids and country rocks. A re-evaluation of the petrologic data from the xenoliths included in the lava flows allows an estimate of the P-T conditions of the magma body; a minimum temperature of 575°C and pressures of 1550–2200 bars can be estimated for the confining rocks around the magma body. Magmatologic data show a temperature of 800–900°C and a P load - 1000 bar. Therefore the roof of the magma body should be present at about 6 km depth. Seismic reflection data reveal the continuous and widespread occurrence of a reflecting horizon ( K ) of all over the geothermal region. This horizon is present at a depth of 5–6 km. By analogy with Larderello, it is interpreted as a fracture interval filled with hot fluids, contact metamorphic minerals and hydrothermal minerals generated in the uppermost part of the granite and the basal levels of the wall rocks. By integrating geophysical and geological data, a two-dimensional gravimetric model of the volcano-plutonic system of Mt Amiata is proposed, with the following features: roof depth = 5–6 km, T = 820°C, d (magma) = 2.15 g cm −3 , d (wall rock) = 2.8 g cm −3 , shape of the intrusion is lens shaped or mushroom-like with possible thickening and roots just below Piancastagnaio. This model fits well with gravimetric data, which show a negative anomaly in correspondence with the uplifted area.