Search

The study of selected logs from the Central-Eastern Iran Microplate (CEIM; area of Arusan) and Sanandaj–Sirjan Zone (SSZ; areas of Esfahan east and Tiran) constrains timing and evolution of the Cretaceous successions, resting unconformably on older sediments or non-conformably on the metamorphic basement. The Cretaceous marine transgression occurred almost synchronously on a levelled topography, documenting a previous deep erosion. Above a basal siliciclastic unit, rudist- and orbitolinid-rich lower Aptian limestone (“Orbitolina Limestone”, Shak Kuh Formation, Taft Formation) were deposited. Later, the stratigraphic evolution of the three studied areas differentiates, documenting changes in the depositional environments, reflecting different subsidence rates. In the Tiran area, marls and cherty limestones covering shallow-water limestones record a deepening trend. A differentiation of depositional environment is observed at Arusan, where conglomerates to the west pass to basinal sandstone and marls to the east. Here, a Coniacian-Campanian reprise of the carbonate production (with skeletal limestones rich in rudists, ostreids, and abundant orbitoidids) is covered by cherty marls. In the Esfahan north area, glauconitic hardground marls covered by chert record important deepening during the early Cenomanian, followed by the reprise of shallow-water carbonate production (middle Cenomanian). The synchronous deposition of Aptian carbonate successions on large parts of the CEIM, SSZ and North-Iranian domains suggests a rapid regional transgression controlled by a sea-level rise. Stratigraphic differentiation occurring in late Aptian–Cenomanian times, recording the onset of tectonic events differently affecting the aforementioned domains, likely related to the opening of oceanic seaways in the CEIM and the SSZ.

The goal of the field itinerary is to illustrate the facies and architecture of a Triassic high-relief carbonate platform (lithostratigraphically known as Esino Limestone; Lombardy, N Italy), similar in age and evolution to the more renowned coeval carbonate platforms of the Dolomites (NE Italy) and the coeval basinal facies. In the central Southern Alps dolomitization is less pervasive with respect to the Dolomites, so that the facies preservation is spectacular, allowing for the observation of detailed depositional and diagenetic features. Furthermore, the visited platform outcrops provide the unique opportunity to observe the sedimentological record of its demise, freezing the architecture of a platform that lasted for about 5 Myr (from close to the Anisian-Ladinian boundary to the Ladinian-Carnian boundary), from the platform top to the basin. The complete section of this Ladinian-Carnian (Middle-Upper Triassic) high-relief carbonate platform is exposed along the Brembana Valley, north of the city of Bergamo. Facies types can be observed in selected outcrops during the field trip, whereas seismic scale geometric and stratigraphic relationships (from the platform top to the slope and basinal setting), can be observed from selected viewpoints. The carbonate platform system reaches a thickness of up to 800 m, with a platform-basin relief of more than 600 m at the end of its evolution. The field itinerary crosses the entire system, from the inner platform to the basin, of one of the best-preserved Triassic carbonate platforms of the Southern Alps of Italy. Inner platform (subtidal to peritidal cycles consisting of oncoidal-bioclastic packstone to grainstone capped by stromatolitic beds), reef (mostly microbial boundstone), slope (clast-supported, early-cemented poorly-selected breccias produced by collapses of the reef-upper slope belt) and basinal facies (dark, well-bedded limestone) facies are exposed in the visited outcrops. During a ‘geological dive’, from the platform top to the basin floor, the diverse subenvironments of the carbonate system can be observed, appreciating the variability of facies along the depositional profile. Each observation is framed in the seismic-scale geometry of the platform that can be appreciated from easily accessible viewpoints. The exceptionally well-preserved facies, as the facies-destructive dolomitization that heavily affects the spectacular coeval platforms of the Dolomites is here rare, permit to document in detail the depositional, early and late diagenetic events. The visited high-relief carbonate system is characterised by a rapid demise, recorded by changes in the facies associations that are exposed in some of the stops representative of different depositional environments: platform top, reef and slope. The abrupt demise of this carbonate system is marked by a major (probably earliest Carnian) sea-level fall associated with a climate change recorded in the different parts of the depositional system by major facies changes. On the platform top the demise is marked by regressive carbonate facies that have different sedimentological characteristics and thickness in the inner platform and in the reef belt. In the basin and on the slope the demise of the carbonate platform is associated with the abrupt input of clay in the basinal setting facing the progradational platform: the seismic-scale onlap relationships between the last prograding clinoform of the Esino Limestone (clast-supported breccias) and the overlying basinal clay can be observed in a spectacular outcrop along the platform slope.

Well-preserved SSE-dipping low-angle normal faults (LANF) active during the Early Permian (Cisuralian) were recognized along the northern margin of the Orobic Basin (central Southern Alps, N Italy). These faults, which escaped most of the Alpine deformations, exhumed the Variscan basement during the deposition of the upper part of the Lower Permian succession (Pizzo del Diavolo Formation). Fault planes show evidence of frictional processes typical of the upper crust associated with hydrothermal circulation, responsible for the deposition of cm to m thick tourmalinite and Uranium mineralization. The recognized LANFs interacted with high-angle normal faults producing half grabens that stored the Lower Permian deposits, where synsedimentary fault activity in their hangingwall is testified by abrupt vertical and lateral facies changes, thickness variations and by soft-sediment deformations. Mesoscopic structures, exposed in the hangingwall of a major LANF (the Aga-Vedello Fault system) along a synthetic high-angle normal fault, include conjugate normal faults, horst-and-graben, domino-style planar and listric faults, which clearly record synsedimentary deformations testified by liquefaction and dewatering structures, typical of pre-consolidation hydroplastic conditions. This xceptional record indicates deformations at shallow crustal level which occurred during the Early Permian along highangle normal faults soling into the LANFs, forming the northern boundary of the Orobic Basin. The outcrop continuity, the perfectly preserved relationships among high- and low-angle normal faults together with the synsedimentary record of fault activity and the occurrence of mesoscopic faults developed during the deposition of the sediments, make this case-study an excellent reference for the analysis of extensional tectonics in synsedimentary conditions. In addition, the occurrence of large LANF systems, typical of a stress regime characterized by a vertical σ1, suggests that the Lower Permian Orobic Basin was dominated by pure extension at least in the study area, alternatively to existing interpretations, which favor a transtensional origin of the basin. Strike-slip tectonics can be responsible for a later partial tectonic inversion of the basin, as testified by the angular unconformity with the overlying Upper Permian succession (Verrucano Lombardo), marking a Middle Permian stratigraphic gap.

The shallowest part (about 3 sec two-way traveltime) of theCROP line M-2A/I, acquired during 1991 in the Bonifacio Strait(between Corsica and Sardinia), has been reprocessed to improveits geological interpretation. The original target of the M-2A/I profilewas the entire crust and therefore the shallowest part was onlypartially interpreted. In this context, the re-processing procedure wascarried out to improve the signal-to-noise ratio and the resolutionof the M-2A/I seismic profile at shallow depth. The geologicalinterpretation of the reprocessed data aimed at the reconstructionof the sedimentary succession and the contact with the underlyingHercynian basement.The M-2A/I seismic profile has been interpreted identifyingdiverse seismic facies, interpreted considering the geological unitsoutcropping to the north (in Corsica) and to the south (in Sardinia)of the seismic profile. The study supports the existence of a thickMesozoic succession, onlapping the Hercynian basement, preservedbelow the Cenozoic succession in the Asinara Gulf, suggesting that theNurra succession continues northward below the sea. The Mesozoic succession is bordered by a major, east-dipping normal fault, east the Asinara Island ridge. The faults recognized in the seismic profile indicate a prevailing strike slip/transtensional tectonics, questioning the role of compressional tectonics suggested in a previousinterpretation. The obtained results also indicate the potential of reprocessing of existing seismic profiles, whose interpretation can be significantly updated thanks to the development of new processing procedures and to the continuous upgrade of the regional geological knowledge.

The structural analysis of large intracontinental wrench faults is fundamental for deciphering the long-term evolution of continental crust in complex areas in terms of their geodynamic evolution and large-scale crustal block displacements. In this contribution, we demonstrate a pre-Miocene dextral activity of the present-day left-lateral Great Kavir - Doruneh Fault System (GKDFS, Central Iran), one of the major intracontinental active strike-slip faults extending from the Afghan border to the Nain region between Central Iran and the Sanandaj-Sirjan Zone. We document important dextral shearing recorded along a segment of the GKDFS, the Arusan Fault System (AFS), located east of Jandaq, close to the present-day active trace of the GKDFS. The AFS include several ENE-WSW striking strands exposed for a length of more than 50km, which couple pre-Cretaceous ophiolites and metamorphic basement units with the Cretaceous succession of the Khur basin. The fault shows transpressional structures consistent with a dextral shear including thrusts and en échelon folds affecting the Cretaceous carbonate units. Paleostress reconstruction based on mesoscopic fault analysis and related folds geometry allowed to establish vorticity parameters indicating that deformation occurred close to a total simple shear regime with a calculated Wk between 0.9 and 1. The enormous Meso-Cenozoic dextral displacements occurred along the AFS and along the entire GKDFS are attested by the up to several hundreds of kilometers offset of the Paleotethys suture zone, from NE Iran to the western border of Central Iran.

The Late Jurassic is a peak time of diversification of reefs with corals, stromatoporoids, calcareous and siliceous sponges, and microbialites during the Phanerozoic. This study focuses on the Callovian–Kimmeridgian carbonate succession of eastern Sardinia, deposited at tropical latitudes on the European passive margin that recorded from the late Oxfordian the evolution from a coated grain-dominated to a reef-bearing carbonate ramp. The coated grain-dominated carbonate ramp (phase 1; Callovian–middle Oxfordian) includes inner ramp ooidal shoals and peloidal packstone in the middle-to-outer ramp. The overlying reef-bearing ramp (phase 2; late Oxfordian–late Kimmeridgian) is characterized by three types (1–3) of bioconstructions. The distribution of these build-ups along the middle-to-outer ramp depositional profile reflects bathymetric parameters, related to the interplay of water energy and light penetration. Type 1 build-ups developed in the proximal middle ramp and consist of 45 m thick, 100 m wide, coral-stromatoporoid boundstone associated with coral–stromatoporoid rudstone–grainstone. Type 2 build-ups, colonizing deeper environments in the middle ramp, are lens-shaped coral–calcareous sponge–diceratid boundstone including stromatoporoids and chaetetid sponges, 1–2 m thick and 3–4 m wide, associated with bioclastic packstone–grainstone. Type 3 lens-shaped calcareous and siliceous sponge–coral–microbialite boundstone build-ups (1 m thick and a few metres wide) formed in lower energy, distal middle-to-outer ramp settings. The evolution of the eastern Sardinian carbonate ramp reflects the Oxfordian–Kimmeridgian spread of the coral–sponge-microbialite reefs along the Tethyan European passive margin.

Comb-veins are mineral-filled fractures oriented perpendicular to fault surfaces, with their intersection with the fault surface generating lineations that are perpendicular to the downdip slip direction. Despite the large occurrence along normal faults within seismogenic extensional tectonic settings (i.e. Greece, Turkey, Italy), their origin, geochemical signature, and kinematics are still poorly constrained. Here we present the first multidisciplinary study, combining field to microscale observations (optical microscope and cathodoluminescence) with geochemical-geochronological analyses (U-Th dating, stable-clumped isotopes, Strontium isotopes, whole-rock geochemistry, and fluid inclusions), on calcite-filled comb-veins cutting through the principal surface of the seismogenic Val Roveto Fault in the central Apennines, Italy. We show that comb-veins precipitated in Late Pleistocene time (between 300 ky and 140 ky) below the present-day outcrop level at a maximum depth of ∼350 m and temperatures between 32 and 64°C from deep-seated fluids modified by reactions with crustal rocks and with a mantle contribution (up to ∼39%). The observed geochemical signature and temperatures are not compatible which those of cold meteoric water and/or shallow groundwater (maximum temperature of 12 °C) circulating within shallow aquifers (≤ 500 m depth) in the study region. Therefore, we propose that deep-seated crust/mantle-derived warm fluids were squeezed upward during earthquakes and were hence responsible for calcite precipitation at shallow depths in co-seismic comb fractures. As comb-veins are rather common, particularly along seismogenic normal faults, we suggest that further studies are necessary to test whether these veins are often of co-seismic origin. If so, they may become a unique and irreplaceable tool to unravel the seismic history and crustal-scale fluid circulation of active faults.

The Triassic crinoid Encrinus aculeatus is described from a single bedding plane of uncertain Pelsonian or early Illyrian or (less probable) late Ladinian origin from Val Brembana (Alpi Orobie, Bergamo, Italy) based on 36 more or less complete crowns and columns. The specimens represent an obrutional echinoderm lagerstatte of the Muschelkalk type. The individuals are semi-adult and juvenile; adult individuals are lacking. Morphological description and comparison with the holotype and additional material from the Lower Muschelkalk and basal Middle Muschelkalk of Upper Silesia (Poland) prove the assignment to Encrinus aculeatus. However, the species concept of genus Encrinus is critical because several characters are inconsistent. E. aculeatus occurs in the Middle Triassic (Bithynian to early Illyrian, ? early Ladinian) of the western Tethys shelf and Peritethys basins (Southern Alps, Balaton Upland, Germanic Basin). Encrinus aculeatus is regarded ancestral to the Upper Muschelkalk (latest Illyrian) E. liliiformis. Until now, E. liliiformis has not yet been proven with certainty from outside the Germanic Basin; references are based on isolated and undiagnostic material.

The comparison of subsidence curves obtained from deep wells in sedimentary basins represents a powerful tool to identify major changes in subsidence distribution, both in time and space. The construction of subsidence curves from 19 wells, covering a time interval from the Cretaceous to the present in the Gabes Basin (Pelagian Domain of the eastern Tunisian Platform), provided the opportunity to reconstruct the subsidence patterns across the basin. Changes in the subsidence rates in different wells allowed the identification of six time-intervals (stages). Stage boundaries are defined by major changes in subsidence trends in the 19 wells: each stage is characterized by changes in the subsidence pattern of groups of wells, likely reflecting episodes of re-organization of the distribution of domains with different trends (increase or decrease) of subsidence. Comparisons among the subsidence curves highlighted, for each stage, parts of the basins with higher or lower subsidence, permitting to identify highs and lows and to reconstruct their significance in the different stages identified. The basin-scale changes in the distribution of subsidence rates reflect regional events of basin re-organization, potentially controlled by syndepositional faults or, for some stages, by halokinesis, due to the presence of salt deposits in the southern part of the study area. The comparison of the subsidence curves permitted to identify domains characterized, in different time intervals, by different patterns of subsidence rates, providing important elements for the characterization of the different stages in the stratigraphic and tectonic evolution of the basin.

The extensional Val Roveto Fault, which is the longest exhumed potentially-seismogenic structure of central Apennines, Italy, is examined to constrain earthquake-related fluid circulation and fluid sources within shallow carbonate-hosted faults. The study focuses on fault-related comb and slip-parallel veins that are calcite-filled and cut through the principal surface of the Val Roveto Fault. We observe multiple crack-and-seal events characterized by several veining episodes, probably related to different slip increments along the fault plane. We show that vein calcite precipitated in Late Pleistocene time below the present-day outcrop level at a maximum depth of similar to 350 m and temperatures between 32 and 64 degrees C from meteoric-derived fluids modified by reactions with crustal rocks and with a mantle contribution (up to similar to 39%). The observed warm temperatures are not compatible with a shallow (

Learning geology requires the knowledge of geological processes that must be applied to the study of specific situations. Geological education requires also three-dimensional (3D) skills that can be improved with training.Important tools for developing 3D skills while teaching geology are geological maps, today rarely used for educational purposes.Modern, digital tools (easily accessible on the internet) can further help in teaching geology, improving students’ skills in visualizing 3D geological objects.We can identify three types of digital tools to integrate education with geological maps: 1) visualize the Earth in 3D view; 2) visualize and navigate 3D geological models; 3) create 3D digital geological models.The integration of the study of the basic rules of geology with the stimulation of the 3D geological visualization is promising in increasing a sensibility toward the Earth Sciences, important for citizens that live in a geologically dynamic country, such as Italy.

The Bathonian-Callovian (Middle Jurassic) Dorgali Formation in eastern Sardinia (Italy) consists of dolomitized oolitic grainstone and records a complex diagenetic history. Petrographic examinations revealed three main phases of replacive (D1, D2) and fracture-filling (D3) dolomites with crystal-size ranges of

The Upper Palaeozoic Godar-e-Siah Complex of Jandaq, Central Iran, comprises three isolated, fault-bounded outcrops exposing Palaeozoic fossiliferous carbonates, volcanics and siliciclastics, which are markedly distinct from the surrounding sedimentary successions. The three outcrops, that emerge below Cretaceous and younger sediments, are the Chah Rizab outcrop, the Godar-e-Siah northern outcrop, and the Godar-e-Siah central outcrop. Their sedimentary successions strongly differ from the typical passive margin successions of Gondwanan affinity that characterize the Yazd, Lut and Tabas blocks of Central Iran and the Alborz in North Iran. To understand the origin of these profound differences, we first calibrated the age of the Jandaq successions: U-Pb radiometric zircons ages, obtained from granitoid boulders in the conglomerates at Chah Rizab and in the Godar-e-Siah northern outcrop, gave a Late Devonian to Mississippian age. Biostratigraphic data from brachiopods and fusulinids from the Godar-e-Siah northern and central outcrops indicate a Pennsylvanian age. The age of the successions is thus post-Visean to Pennsylvanian. The petrographic composition of the siliciclastic deposits indicates the erosion of a magmatic arc. To understand where the Jandaq complex could have been located at that time, we have assessed the palaeobiogeographic affinity of the faunas. The collected brachiopods and fusulinids assemblages are mostly similar to coeval faunas from Spain, Donbass, Urals, and Yukon Territory (Canada) and have a North-Palaeotethyan affinity. The Godar-e-Siah Complex of Jandaq likely represents part of the southern active margin of Eurasia (northern margin of the Palaeotethys), in contrast to the surrounding Central and North Iran blocks, which were at that time located along the southern margin of the Neotethys. Our investigations confirm a complex palaeogeographic evolution for the studied outcrops, suggesting that they represent fragments of the southern Eurasian active margin - today preserved in NE Iran - displaced by crustal-scale wrench motions related to the opening and closure of the Sabzear Ocean and to the Cenozoic activity of the Great Kavir-Doruneh Fault and its possible precursors.

New age estimates obtained via Strontium Isotope (87Sr/86Sr) Stratigraphy and new paleoclimatic data are here presented for the Miocene Chilcatay and Pisco formations exposed in the East Pisco Basin, an Andean forearc basin of southern Peru, which is renowned worldwide for its exceptional content of fossil marine vertebrates. Mollusk and barnacle shells, carbonate nodules, and shark teeth were collected along three stratigraphic sections for applying Strontium Isotope Stratigraphy on both carbonates and phosphates. To avoid diagenetic biases, mollusk and barnacle shells were analyzed in detail by means of optical and scanning electron microscopy, cathodoluminescence, and inductively coupled plasma-optical emission spectrometry, whereas only the enameloid from the best-preserved shark teeth was sampled. The obtained 87Sr/86Sr ages confirm a late early Miocene (Burdigalian) age for the Chilcatay strata, and reveal middle Miocene (Langhian to Serravallian) ages for the lower Pisco unit (i.e., the P0 sequence) – a result that matches the relatively archaic aspect of its cetacean fossil assemblage. New and literature data about the fossil assemblage of the lower Pisco beds highlight the presence of several thermophilic invertebrates and vertebrates, thus suggesting a warm-water, tropical paleoenvironment for this middle Miocene sequence. Such a paleoenvironmental scenario recalls the warm conditions associated with the Chilcatay Formation, rather than the cooler setting inferred for the remainder of the Pisco Formation (i.e., the P1 and P2 sequences). This pattern likely reflects the late Miocene trend of global cooling, as well as a middle to early late Miocene strengthening of the Humboldt Current.

Fault inversion may lead to significant obliteration of earlier tectonic structures, thus preventing the straightforward interpretation of the complete kinematics and deformation history of faults. We adopt a multidisciplinary approach to: (1) reconstruct the tectonic evolution through space and in time of the extensionally-inverted Mt. Tancia Thrust (Central Apennines, Italy); (2) understand the deformation mechanisms and the transition and reactivation of compressional structures during negative tectonic inversion; and (3) constrain the origin of fluids involved during tectonic processes. To this end, we combined: (1) detailed geological mapping and multiscale structural analysis; (2) illite-smectite paleothermal indicators; (3) C, O, and clumped isotopes on calcite mineralizations and (4) K–Ar dating of authigenic and/or syn-kinematic illite from the Mt. Tancia Thrust fault rocks. We show that shortening occurred between ~9 and ~7 Ma, during possibly multiple events of fluid overpressure and shear rupturing involving fluids entrapped over long term within the host rocks. Post-compressive tectonic inversion occurred at ~3 Ma under fluid pressure fluctuations during shear events with an input of meteoric-derived fluids. Tectonic inversion is spatially confined within the first few metres below the thrust surface in a volume dominated by the partial overprinting, folding, transposition, and re-utilization of the earlier compressional fabric.

Lower Permian continental deposits of the fault-controlled Orobic Basin (Central Southern Alps; Northern Italy) include alluvial fan facies interfingering with muddy basin-floor deposits, consisting of three facies associations: heterolithic fine-grained siliciclastic facies, laminated sandstone facies, and oncoidal limestone facies. Besides oncoidal and microbial limestones, carbonates occur as nodules in sandy tabular beds within the laminated sandstone facies association. Microfacies analyses distinguish several types of oncoidal carbonate (consisting of an alternation of microbial carbonate and fibrous calcite) and carbonate nodules. Each type of carbonate has been characterized in terms of δ18O and δ13C. The two types of carbonate in the oncoids record a stable δ18O and a slightly varying δ13C, whereas the isotope composition of the calcite in nodules is completely different. Carbonate nodules in sandy beds of the laminated sandstone facies association have a diagenetic origin as indicated by cross-cutting relationships between nodules and lamination; the nodules are interpreted as groundwater calcrete, formed in the subsurface at the top of the unconfined water table. The exclusive sedimentation of oncoidal carbonate facies within siliciclastic deposits indicates that when oncoids were formed in ephemeral shallow ponds, siliciclastic input was minimal. The sedimentological and geochemical characteristics of the studied succession and the stable isotopic composition of the oncoids (the absence of covariance between δ18O and δ13C excludes deposition in evaporating basins) indicate persistent stable conditions for sufficient time to permit growth of centimeter-sized oncoids. Oncoids are interpreted to have formed in spring-fed ponds and outflow channels, with flowing, clean water, at the toe of major alluvial fans. Episodes of rapid delivery of sand and silt-sized sediments by flash floods, with an oscillating water table, caused the observed facies alternation. The precipitation of calcareous cements close to the water table surface produced nodules in sandy layers. Carbonate precipitation within laminated sandstone reduced porosity and permeability, causing a strong compartmentalization in the well-bedded continental succession.

Arragoni et al. (2016) suggest in their paper published on Tectonics that the carbonate succession of Eastern Sardinia represents a Cenozoic fold-and-thrust belt, related to the Alpine orogenesis. According to these Authors, this supposed fold-and-thrust belt represents the southward prosecution of the Alpine Corsica collisional chain and the missing link between the Alpine Chain and the Calabria-Peloritani domain. Field evidence and the published literature document instead that all the surfaces that Arragoni et al. interpret as thrust are actually stratigraphic contacts. The balanced geological section of Arragoni represents thus a geometric exercise missing the basic data needed to nurse the proposed model and it does not reflect the geology of eastern Sardinia. The data provided by Arragoni et al. (2016) do not supported the presence of an Alpine thrust and fold belt in eastern Sardinia and this paper may suggest to the geological community a misleading interpretation of the geodynamic evolution of the Alpine and Mediterranean area.

The demise of the high-relief, steep-slope, prograding Ladinian-Early Carnian carbonate platforms of the Esino Limestone (Central Southern Alps of Italy) is marked by subaerial exposure of the platform top associated with different erosional (mainly karst-related), depositional and diagenetic processes (Calcare Rosso). The exposure-related deposits consist of three major facies associations: 1) residual soils with thin lenses of conglomerates with black pebbles, and, locally, weathered vulcanites; 2) chaotic breccia lenses irregularly distributed in the uppermost part of the Esino Limestone carbonate platform, interpreted as collapse breccias in karstic setting: 3) inter-supratidal carbonate cycles with dissolution and development of paleosols and tepee structures. Facies distribution follows the sub-environments of the underlying Esino Limestone. Facies 1 and 2 typically characterize the core of the platform, covering the underlying inner platform facies. Facies 3 instead develops toward the edge of the platform, above reef-upper slope facies of the prograding facies of the Esino Limestone. The thickness of facies 3 decreases toward the core of the platform. Facies distribution reflects differences in the accommodation space and sedimentary processes from the rim (highest accommodation, favouring the deposition of peritidal-supratidal carbonates) to the core (reduced accommodation, causing pedogenesis and karstification) of the carbonate system. The observed thickness changes may be controlled by different factors: 1) syndepositional tectonics, 2) subsidence induced by magmatic activity or 3) differential subsidence controlled by the stratigraphic architecture of the Esino Limestone platform and adjoining basins. As evidence of tectonics was not observed and the presence of volcanic bodies is only documented tens of km away from the study area, the scenario involving the creation of accommodation space by compaction of the basinal sediments (resedimented, fine-grained calciturbidites) during the progradation of the carbonate platform is here investigated. Numerical modelling was performed to verify the compatibility of compaction-induced subsidence with the observed depositional architecture. The models were built to simulate the architectural evolution of the platform by progressively adding layers from deepest to shallowest, while compacting the underlying sediments, in order to evaluate compaction-induced subsidence (and accommodation space for the Calcare Rosso) after the deposition of the youngest platform strata. Modelling results allow us to conclude that the wedge geometry of the Calcare Rosso, deposited on top of the extinct Esino carbonate platform, can be explained by subsidence controlled by compaction of the basinal sediments present below the early-cemented, fast prograding platform slope deposits.

Continental successions in fault-controlled extensional–transtensional basins store a wide range of clastic deposits from various depositional environments, representing a challenging target for hydrocarbon exploration. Recent advances in field-based facies analysis and genetic interpretation of these sediments show that these successions are characterized by great variability in terms of volume, geometry, facies, and stacking patterns. This variability derives from a number of factors that govern the sedimentary processes, such as tectonic setting, basin size and morphology, type and amount of sediments, and climate. The study focuses on a well-exposed Early Permian continental succession (Southern Alps, northern Italy), which was deposited in an extensional–transtensional tectonic regime under a semiarid to arid climate. The study area is characterized by a thick (more than 1000 m) succession of prevailing continental clastics with intercalations of ignimbritic flows and tuffs (Pizzo del Diavolo) Formation resting on up to 800 m of prevailing pyroclastic flows (Cabianca Volcanite). These units are unconformably covered by the Upper Permian alluvial sediments of the Verrucano Lombardo. Sedimentological features reflect a proximal fan system where mass-flow phenomena dominate, a distal fan-terminal setting with prevailing sandy sheet-flow processes and a silty floodplain environment, where sheet-flood events dominate. Laterally continuous siltstones and dark shales with carbonate nodules and layers of microbial carbonates in the most depressed part of the basin indicate alternating conditions of shallow lake and desiccated floodplain. Syndepositional tectonic activity is documented in the succession by rapid vertical and lateral facies changes. In this study, we present a data-constrained reconstruction of the depositional architecture of the basin, a description of depositional processes and depositional environments, and a model of facies distribution. Outcrop data, integrated with laboratory analyses, provide a detailed understanding not only of the small-scale elements of the system (sub-seismic scale) but also of the entire basin, focusing on how those elements are interrelated. The studied succession can be considered an interesting outcrop analogue for subsurface extensional–transtensional basins, potentially useful to predict reservoir properties for similar subsurface settings.

The petrographic, cathodoluminescence (CL), stable isotope, and microthermometry investigation of inner platform facies of the pervasively dolomitized carbonate platform of the Norian (Upper Triassic) Dolomia Principale (Southern Alps, N Italy) identified two major dolomite phases. An early replacement fabric-retentive dolomite (D1 and D2, respectively replacing the sedimentary facies - from fenestral mudstone/wackestone to bioclastic packstone and mudstone and stromatolites- and early marine cements) is followed by a later, vug- and fracture-filling dolomite cement phase (D3, planar-s texture). The fabric-retentive dolomitized carbonates ( The δ13C values of the investigated dolomites (D1, D2, and D3) show a narrow range of variation (2.0–3.1‰ VPDB), pointing toward a fluid-buffered system. Differently, the δ18O values largely varies, ranging from −12.8 to +1.9‰ VPDB. In this range, D3 values cluster distinctively between −6.0 to −12.8‰ VPDB with respect to D1 and D2, which cluster from about −4 to +1.9‰ VPDB. The estimated oxygen isotope composition of the parent fluid of D1 and D2 (~0 to −5‰ VSMOW) suggests possible contributions from marine to slightly evaporated seawater, which is consistent with the arid climate and some basin restrictions suggested by earlier studies, whereas that of D3 (+1 to +5‰ VSMOW) is consistent with burial fluids. The followed integrated approach highlights the possibility to better characterize the occurrence of multiple diagenetic events in time and space, as well as their feedback effects on the porosity evolution of dolomitized carbonate reservoirs, framing the diagenetic events at regional scale.

The evolution of the Cambrian-Middle Ordovician carbonate systems in the east-central Tarim Basin, northwestern China, has been investigated using 2D seismic profiles and well data. Interpretation was performed on seismic profiles flattened along an originally horizontal surface (base of the Cambrian), to remove the effects of post-depositional deformations. Six seismic facies differently arranged in six seismic stratigraphic units record four major stages of architectural evolution, from ramp to flat-topped systems, with differences from north to south: (1) the onset of a homoclinal ramp over a clayey unit at the beginning of Early Cambrian; (2) the development of a prograding carbonate platform characterized by restricted (evaporitic) facies in the inner platform domain during Early Cambrian to Late Cambrian; (3) the development of a first prograding and a aggrading (retrograding to the north) platform during Lower Ordovician; (4) the development of a prograding/retrograding to aggrading final platform during Middle Ordovician. The basinward (eastward) progradation of the carbonate platform edge has been reconstructed in time steps, highlighting differences from the north to the south of the study area in terms of amount of progradation, platform-to-basin relief and depositional surfaces, likely controlled by differences in subsidence and environmental factors. The identification of the four major stages in the evolution of the lower Paleozoic succession of the Tarim Basin was likely controlled by changes in the rate of creation/destruction of accommodation space, due to the interplay between eustatic changes and tectonic events. The demise of the Cambrian to Middle Ordovician carbonate system in the study area is associated with a major tectonic event, recorded by a tilting of the succession toward the east (onlapped by sediments coming from the east) and an uplift (bulge) of the western part of the study area.

Here, we describe the Permian–Lower Triassic sedimentary succession of South Pamir and the associated biota of conodonts, foraminifers and brachiopods. The studied succession comprises the Carboniferous-Lower Permian siliciclastic Uruzbulak and Tashkazyk formations (Bazar Dara Group), which are unconformably covered by upper Lower to Upper Permian units, deposited both in platform settings (Kurteke Formation), and on the slope and basin (Kochusu Formation, Shindy Formation, Kubergandy Formation, Gan Formation, and Takhtabulak Formation). These formations comprise bioclastic limestones, cherty limestones, shales, volcaniclastic rocks, basalts, sandstones and conglomerates, and are locally very rich in fossils (fusulinids, ammonoids, brachiopods, corals and conodonts). The Permian succession is then overlain by shallow water carbonates of the Induan to Anisian Karatash Group. Subsidence analysis and volcanics of the Permian and overlying Triassic successions constrains the timing of rifting of South Pamir from Gondwana in the Early Permian (=Cisuralian), and its docking to Central Pamir, the Eurasian margin and the interposed volcanic arcs at the end of the Triassic. The sedimentary successions of the Pamirs represent a key-point to refine the correlations between the Tethyan regional scale and the International Time Scale. The analyses of the fusulinids and conodonts of the Kubergandian and Murgabian stratotypes of SE Pamir suggest that: (1) the upper Bolorian and the lower part of the Kubergandian correlate to the upper Kungurian; (2) the upper Kubergandian and the lower Murgabian correlate to the Roadian; (3) the mid-upper Murgabian correlates to the Wordian; (4) possibly the uppermost Murgabian and the lower Midian correlate to the lower Capitanian. The Kubergandian is thus a defined regional stage, based on fusulinids, ammonoids and conodonts and can be correlated to the Kungurian and the Roadian; still problematic remains the Murgabian correlation which needs to be investigated and resolved in other Tethyan sections.

Stratigraphic and sedimentologic studies of the norian succession outcropping in rhe Lombardy Basin allowed the reconstruction of the paleogeographic and strucural evolution oi this area, 1) restricted lagoon and tidal flat are the most common deposits ar the Carnian-Norian boundary (Lower Member of the Dolomia Principale); 2) these are overlain by a thick inner platform succession organized in shallowing upwards cycles (lower Dolomia Principale), with the exception of Idro Lake area where intraplatform basin already generated; 3) the overlying middle-upper Dolomia Principale is dissected by synsedimentary faults with subsequent widespread development of intraplatform basin, margin, and slope facies with marked asymmetric distribution; the inner platform was locally emerged; 4) in the uppermost Dolomia Principale buildup margins become more abundant and the platform partially prograded on the basins; 5) at last the platform drowns and terrigenous sedimentation becomes prevalent (Riva di Solto Shales). The drowning of the platform is favoured by the lack of carbonate production, due to clay pollution and climatic changes in an area with high subsidence rates. The observed asymmetric distribution of buildup margins and fault-scarp related breccias, which outcrop on the western side of the basins west of Iseo Lake and bounding the eastern side of the basins east of Iseo Lake, allows us to propose a model of norian ensialic asymmetric rifting for the Lombardy Basin. This asymmetric rifting could be explained by interpreting the Lombardy Basin as a pull-apart basin, linked to transtension with E-W trending faults., Rivista Italiana di Paleontologia e Stratigrafia (Research In Paleontology and Stratigraphy), V. 98, N. 1

The successions exposed in the Pin and Spiti valleys, a classical area for the Tethyan Triassic, provides an extraordinarily complete sedimentary and paleontologic record and is thus well-suited to check the validity of global eustatic charts and applicability of sequence stratigraphic concepts. New detailed stratigraphic data allowed us to present a revised lithostratigraphic scheme - largely based on previous works by Hayden (1904) and Srikantia (1981) - which can be directly compared with successions exposed all along the Tethys Himalaya from Zanskar to Tibet. The Permian/Triassic boundary represents a major break in sedimentation, with time gaps of up to several Ma testified in the upper Pin valley. In the Induan to Anisian, the Tamba Kurkur Fm. mainly documents global eustatic changes, with transgressive stages characterized by sedimentation of condensed nodular Lmestones on the outemost shelf/uppermost slope (e.g., Griesbachian/Early Dienerian, Spathian) and regressive stages marked by mudrock deposition on the continental shelf (e.g., Late Dienerian/Smithian). A glauconitic condensed horizon occurs at the Anisian/Ladinian boundary, and the top of the formation reaches the Early Ladinian in more complete proximal sections. Greater clay supply characterizes the late Early Ladinian, but accumulation rates remain low in the lower part of the Hanse Group(Kaga and Chomule Fms.), to increase sharply in the late Early to early Late Carnian ("Grey beds"), reaching 100 m/Ma in the latest Carnian (Nimaloksa Fm.). At least nine, third- to fourth-order transgressive,/regressive sequences can be recognized in the Nimaloksa Fm. and Alaror Group, where facies distribution pattems indicate that the Spiti continental margin deepened towards the north. The Nimaloksa Fm. documents progradation of a carbonate ramp in the latest Carnian(Lower Member), followed in the Early Norian by subtidal mixed carbonate/terrigenous sedimentation (Middle Member) and by platform carbonate deposits (Upper Member). Next, the major disconformity at the base of the Alaror Group testifies to an extensional tectonic event, followed by rapid increase in quanzo-feldspathic detritus in the late Early Norian. Siliciclastic supply is reduced only during flooding stages, marked by oolitic ironstone or phosphatic condensed horizons ("Juvavites beds", "Monotis shale'); cleaner waters foster local development of knoll reefs round the Early/Middle Norian boundary ("Coral limestone'). Accumulation rates gradually begin to decrease before the close of the Triassic, when the "Quartzite series" records a sharp regressive event, followed by renewed transgression at the base of the Kioto Group., Rivista Italiana di Paleontologia e Stratigrafia (Research In Paleontology and Stratigraphy), V. 101, N. 3

U–Pb zircon ages from volcanic rocks of Early Permian age (Southern Alps, Lombardy), associated with fault-controlled transtensional continental basins, were determined with the laser ablation (LA)-ICP-MS technique. Four samples were collected at the base and at the top of the up to 1000 m thick volcaniclastic unit of the Cabianca Volcanite. This unit pre-dates the development of a sedimentary succession that still contains, at different stratigraphic levels, volcanic intercalations. Age results from a tuff in the basal part of the unit constrain the onset of the volcanic activity to 280 ± 2.5 Ma. Ignimbritic samples from the upper part of the unit show a large scatter in the age distribution. This is interpreted as the occurrence of antecrystic and autocrystic zircons. The youngest autocrystic zircons (c. 270 Ma) are thus interpreted as better constraining the eruption age, constraining the duration of the volcanic activity in the Orobic Basin to about 10 Ma. The new geochronological results compared with those of other Early Permian basins of the Southern Alps reveal important differences that may reflect (1) a real time-transgressive beginning and end of the volcanic activity or (2) the complex mixing of antecrystic and autocrystic zircon populations in the analysed samples.

Exceptionally preserved Early Permian tetrapod trackways from the Orobic Basin (Central–Western Southern Alps) offer a unique opportunity to investigate in detail locomotion in fossil vertebrates that lived on continental European landmasses. Herein are reported the results of a study on several tetrapod trackways that display a large variety of behavioral, gait and substrate related extramorphologies. They clearly document the transition from terrestrial–underwater walking to swimming and are assigned to the compound ichnotaxon Batrachichnus C Lunichnium. The use of the “C” symbol is here introduced for the first time as nomenclatural indication of a Compound trace. Producers were probably small-sized temnospondyl or lepospondyl (microsaurs) amphibians. Comparisons with living urodelan anatomy and mechanics provide evidence for conservatism of locomotor mechanics in evolutionary history among amphibians. The derived model for locomotor kinematics in Early Permian amphibians provides a reference for interpreting transitional land-to-water trackways. The shift from walking to swimming behavior in early tetrapods, as in extant urodelan amphibians, is described as a complex balance between different dynamics.

The skill in “reading” two-dimension representations (typically geological maps) as symbolic images of the real world is critical for a geologist. Teachers have thus to face the difficulties that several students have when reading geological maps. Furthermore, when students fail, the consequence is often a frustration with the successive reject of the subject. The skill to understand 3D objects can be typically evaluated with the analyses of the geological cross sections produced by geology students. Spatial thinking skills are related to two main facts: 1) a natural predisposition in the visualization of complex objects and 2) a good training to develop 3D visualization skills. Whereas in the first case the role of the teacher is often ancillary, in the second case, teachers need to find a way to improve 3D visualization skills with specific tools and specific exercises. In the past, the supports for this educational training was provided by physical models or by perspective images. The development of 3D geological software packages recently provided tools for geological modeling that found applications in different fields of geology. In the academic formation, nevertheless, students learn the basic of 3D geological reconstruction with classical tools, whereas the use of 3D software packages is limited during their education and they mostly meet these tools for professional applications after their degree. At the Earth Department of the Universita degli Studi di Milano we introduced the educational use of a 3D modelling software (Move ™, produced by Midland Valley Exploration LTD and provided to our department in the frame of the Field Mapping Initiative) since the Bachelor courses (on voluntary basis), in order to stimulate the 3D visualization skills of the students. Move™ has been used on simple geological situations selected from a number of educational books: students were guided in the production of 3D geological models from digital raster images of simple geological maps, following all the process of data input and elaboration (including DTM production). 3D visualization at different step of the model development strongly improved the skill of the students in the visualization of geological volumes, speeding up the process of learning. The feedback of this procedure has been strongly positive, with students that, after learning the basic use of this 3D modelling software, asked for the application of the method to real and more complex geological cases. The use of 3D software packages for the modelling of geological bodies during the educational program potentially increased the precision in the geological mapping process, as the students were able to verify that also minor inaccuracies in data representation are strongly highlighted when geological data are handled in 3D models.

The Cimmerian orogen resulted from the collision and accretion of several Perigondwanan blocks to the southern margin of Eurasia between the Late Triassic and Early Jurassic, following the closure of the Palaeotethys ocean. Remnants of this orogen discontinuously crop out in N (Alborz range) and NE Iran (Mashhad–Fariman area) below the syn- to post-collisional clastic successions of the Shemshak Group (Upper Triassic–Middle Jurassic) and the Kashaf Rud Formation (Bajocian). In NE Iran rock associations exposed in the Binalood Mountains, Fariman and Darreh Anjir areas include mafic–ultramafic intrusive rocks, basalts, silicoclastic turbidites and minor limestones, which have been interpreted in the past as ophiolitic remnants of the Palaeotethys ocean. Original stratigraphic, structural, geochemical and geochronological data, described in this paper, suggest a different interpretation. The volcano-sedimentary units of Fariman and Darreh Anjir complexes where deposited during Permian in a subsiding basin were siliciclastic turbidites, derived from the erosion of a magmatic arc and its basement, interfinger with carbonates and basaltic lava flows with both transitional and calc-alkaline affinity. The coexistence of magmatic rocks with different geochemical signature and the sedimentary evolution of the basin can be related to a supra-subduction setting, possibly represented by a fault-controlled intra-arc basin. The Fariman and the Darreh Anjir complexes are thus interpreted as remnants of a magmatic arc and related basins developed at the southern Eurasia margin, on top of the north-directed Palaeotethys subduction zone long before the collision of Iran with Eurasia. They were later involved in the Cimmerian collision during the Triassic. New radiometric ages obtained on I-type post-collisional granitoids postdating the collision-related deformational structures suggest that the suture zone closed before mid-Norian times. Deformation propagated later northward into the Turan domain involving the Triassic successions of the Aghdarband region.

Quantitative analysis of depositional systems using numerical models can provide insights into the interaction of sedimentological and diagenetic processes, difficult to interpret from observation of the geological products alone. Numerical models can highlight the interactions between controlling parameters, and generate best estimate simulations of case studies from the geological record. Different data sources (e.g., outcrop data, uniformitarian constraints, paleogeography) need to be considered in the process of defining the parameters required to produce models that honour individual case studies. We present a best-estimate forward model of a high-relief Triassic carbonate platform (Southern Alps, Italy) generated using CARB3D+, a 3D process-based forward modelling package able to simulate sedimentary facies, geometries and early diagenesis of isolated carbonate platforms. The parameters used for the presented forward model have been deduced by the study of architectural, sedimentological and diagenetic features of the platform, and by data from modern and ancient analogues. Sensitivity analysis is used to tune values of the parameters within ranges defined from field, laboratory and uniformitarian constraints. Critical evaluation of the model allowed 1) verification of the validity of the used parameters; 2) evaluation of the interaction between controlling parameters; 3) development of a numerical model that can be used for quantitative elaborations. Furthermore, the process of generating the numerical model required a detailed interpretation of field and laboratory data, crucial to define the required input parameters. Modelling the studied carbonate platform also enabled evaluation of the effects of the interaction between productivity, environmental energy and creation of accommodation space, promoting the understanding of their role on the architecture of carbonate systems. Forward modelling also allows the integration of data from conventional data sets with data from present-day observations and seismic geometries, promoting a transition from a qualitative to a semi-quantitative/quantitative sedimentological approach. Forward models can further be used to parameterise petrophysical properties of complex geobodies, with potential application for the management of georesources.

The Tethyan region is a major petroleum province. The paleogeographic position and tectonic history is a major control on sedimentation across the region, and this has influenced the sequestration of hydrocarbons in the region. The North African-Arabian plate evolved along the Tethyan margins (Proto-Tethys, Paleo-Tethys, Neo-Tethys) from Pre-Cambrian to Recent. Paleogeographic maps have been reconstructed for selected time intervals: Cambrian, Late Ordovician, Early Devonian, Early Permian, Permian-Triassic boundary, Norian, Callovian, Aptian, Cretaceous-Cenozoic boundary, and Late Eocene. For each time interval both the general picture of the major plate tectonic configuration and a detail of the paleogeography and paleoenvironment of North Africa to the Middle East are presented. On these maps, the major paleoenvironmental settings (from continental to shallow marine and deep ocean) are shown for the area stretching from North Africa to Afghanistan in all the selected time slices. Besides the major tectonic events, the global climate evolution and their interplay are discussed, which in some cases led to significant biotic turnovers or even to mass extinctions (e.g., Late Ordovician, Permian-Triassic boundary, Cretaceous-Cenozoic boundary). Paleogeographic maps have been compiled from literature, selecting those based on sound paleomagnetic/paleobiogeographic data. Each map is accompanied by the description of the major tectonic events that characterized the considered time interval. When contrasting paleogeographic reconstructions were available, their differences have been discussed. In general, major differences concern the interpretation of the setting and positioning of the microplates and terranes between the major continental plates. This chapter provides the introductory overview of the paleogeographic location and general tectonic history of the Tethyan margin through time. This is elaborated on and linked with depositional systems and hydrocarbon endowment in the subsequent chapters.

The Anisian succession of Nakhlak (in Central Iran) is characterized by a siliciclastic succession with minor carbonate units, with massive carbonate mounds up to 50 m thick in its upper part. The mounds, constrained in age to the late Bithynian (Ismidicus Zone) by ammonoids and conodonts, are characterized by a flat top and a lateral pinch-out marked by clinostratified slopes (about 15° in dip). Stratigraphic and microfacies analyses document an inner part of the mound characterized by massive microbial carbonates with open-space structures (stromatactis) filled with fine-grained internal sediments and marine cements. Isolated sponges (up to 5 cm), serpulids and bryozoans are present, which grew on the calcimicrobial limestone. A narrow bioclastic margin (mainly with crinoids and brachiopods) produces most of the slope facies (consisting of bioclastic grainstone and packstone, with intraclasts from the inner part of the mounds) which interfinger basinward with volcaniclastic sandstones. The demise of carbonate productivity is marked on the top of the carbonate mounds by a condensed surface, rich in ammonoids, glaucony grains, and articulated crinoids, documenting a rapid drowning. Paleolatitude data support deposition in a tropical setting, and sedimentological constraints indicate deposition close to the fair-weather wave base, within the photic zone. The late Bithynian Nakhlak carbonate mounds developed before the appearance (documented since the Pelsonian in different parts of the world) of scleractinians which, despite the favorable environmental conditions, are absent at Nakhlak. The Nakhlak mounds thus represent one of the last occurrences of the microbial factories (which developed after the Permo-Triassic extinction event and persisted for most of the Middle Triassic, but with a gradually increasing role played by scleractinians) before the first appearance of the Mesozoic corals.

The interplay of sea-level fall, climate, and sedimentological changes is recorded across two sequence boundaries at the top of two Triassic carbonate platform systems in the Western Tethys (earliest Carnian and Norian-Rhaetian boundary in age, paleolatitude 18°–25° N). The sea-level falls caused subaerial exposure of the platform top and decreased carbonate production, leading to starvation in the intraplatform basins, followed by deposition of shale. Evidence of freshwater input indicates that the change in sedimentation was driven by increased rainfall on the previously arid European hinterland and Tethys coast. A uniformitarian approach (Holocene sea-level changes and global warming are coupled with changes in the distribution of precipitation) implicates global cooling as the probable cause of the observed sea-level, climate, and sedimentological changes. Global cooling likely triggered the sea-level fall by increased storage of fresh water in continental settings and change in seawater density, probably coupled with ephemeral ice sheet development, possible even during greenhouse intervals such as the Triassic. Furthermore, global cooling caused a shift toward the equator of the poleward boundary of the arid belt. This model is supported by the traceability of the sequence boundaries and climate-sensitive facies from the Tethys shelf up to the European continent. The observed association of global climate changes, sea-level fall, sedimentological changes, and shift toward humid climate documents how climate-sensitive facies record the control exerted by global changes on local sedimentation.

Numerical models were used to investigate the effects of differential compaction on strain development and early fracturing in an early cemented high-relief Triassic carbonate platform prograding onto basinal sediments, whose thickness increases basinward. Results show that basinal sediment compaction induces stretching of internal platform and slope strata in prograding platforms. When sediments are early cemented, such extensional strain is accommodated by the generation of syndepositional fractures. The amount of stretching is predicted to increase from the oldest to the youngest layers, due to the thickening of the compactable basinal sequences towards the external parts of the platform. Stretching is also controlled by the characteristics of the basin: the thicker and the more compactable the basinal sediments, the larger will be the stretching. Numerical modelling has been applied to the Ladinian–Early Carnian carbonate platform of the Esino Limestone (Central Southern Alps of Italy). This case study is favourable for numerical modelling, as it is well exposed and both its internal geometry (inner platform, reef and prograding clinostratified slope deposits) and the relationship with the adjacent basin can be fully reconstructed, as the Alpine tectonic overprint is weak in the study area. Evidence for early fracturing (fractures filled by fibrous cements coeval with the platform development) is described and the location, orientation and width of the fractures measured. The fractures are mainly steeply dipping and oriented perpendicularly to the direction of progradation of the platform, mimicking local platform-margin trends. The integration of numerical models with field data gives the opportunity to quantify the extension triggered by differential compaction and predict the possible distribution of early fractures in carbonate platforms of known geometry and thickness, whereas the interpretation of early fractures as the effects of differential compaction can be supported or rejected by the comparison with the results of ad hoc numerical modelling.

The Upper Anisian to Early Carnian succession of the Middle Val Brembana–Pegherolo Massif (Central Southern Alps of Italy) records a complete depositional cycle from platform inception to growth, demise and rebirth. The depositional architecture of this system reflects different evolutionary stages: an inception stage which postdates a previous drowning of an Anisian carbonate platform with progradation of the carbonate platform from the nucleation areas, an aggradational stage with increasing water depth in the basins, a progradational stage where steep slopes composed of margin-derived breccias develop and a final crisis corresponding to the subaerial exposure of the platform top, followed by the deposition of shales in the basin before the rebirth of a different type of carbonate factory. The record of this evolution reflects the effects of the change in accommodation space (interplay of subsidence and eustacy), which controls the type and storage sites of the sediments produced by the carbonate factory. The effects of the changes in accommodation space are recorded in the shallow water platform as well as in the intraplatform basins, where the sediments, delivered at different rates from the platform top are stored. As a consequence, the aggradational stage corresponds to reduced sedimentation in the basins (i.e. sediments are stored on the platform top) whereas during progradation resedimented limestones are more common in the basin. Subaerial exposure rapidly halted the carbonate production on the platform top, while a major input of shales (probably reflecting a climate change and/or lowering of the base level) is recorded in the basin, where shales onlap the slope of the previous carbonate system. The rebirth of the carbonate factory after subaerial exposure of the platform top is characterized by a different composition of the carbonate factory, probably reflecting changes of the environmental conditions. The step-by-step recording of the evolution of the carbonate system represents a unique opportunity to record a seismic-scale complete evolutionary cycle of a carbonate system in its different sub-environments, from the platform top to the basin.

Quantitative analysis of sediment composition was performed on a kilometre wide section of Upper Tithonian low relief (up to 70 m), gently inclined (3° to 15°), sigmoidal carbonate clinoforms (eastern Sardinia) to identify changes in sediment composition along the slope and across the studied succession. These changes may reflect modifications of the carbonate factory and of processes responsible for sediment transport. Point-count analysis of carbonate microfacies, Q-mode/R-mode cluster analysis and Spearman’s rank provided a composition-based classification of microfacies and highlighted relationships among sediment components. The studied clinoforms are mainly composed of non-skeletal grains (70%), such as peloids and lithoclasts, together with micrite and cements and only a limited contribution from coated grains (2%). Among skeletal grains (28%), the greatest contribution derives from a coral–stromatoporoid–encruster reef that provided 15% of the components. Crinoids, brachiopods and other along-slope thriving biota provided nearly 5% of the allochems, whilst fragments of molluscs (gastropods, bivalves and diceratids) from the backreef sourced another 2%. The contribution of platform interior biota is negligible (1%). The association of composition-based facies varies along the slope. The upper slope beds consist of coral-stromatoporoid grainstone to rudstone; the middle slope deposits are dominated by encruster-lithoclast grainstone and packstone. At the lower slope, peloidal lithoclastic packstone as well as brachiopod–crinoidal wackestone prevail. Also the association of skeletal grains changes along the slope. The encruster–frame builder association typifies the upper slope whilst encrusters characterize the middle slope sediments. In the lower slope encrusters are equally represented as the brachiopod–crinoid association. Along-slope compositional changes evidence a scarce downslope transport of frame builders and a progressive enrichment in along-slope thriving biota. Quantitative analysis of microfacies allowed the sigmoidal clinoforms to be grouped into six sets. Each set gathers sigmoids with a similar sediment composition. Coated grains are dominant in the first set whilst they are lacking in the overlying sets reflecting a change in the carbonate factory. Other major compositional changes among the sets concern the relative amounts of peloids, micrite, frame builders (corals and stromatoporoids) and encrusters. The contribution of peloids varies inversely to that of cements and micrite as evidenced in the third and fifth sets which, respectively, record the highest occurrence of peloids or cement and micrite. Variations in the amount of frame builders and encrusters are instead non-linear. High percentages of both frame builders and encrusters, as recorded in the second and fifth sets, are related to low amounts of peloids and lithoclasts that probably reflect episodes of reduced background sedimentation. This study demonstrates that quantitative analysis of carbonate microfacies represents a powerful tool that can improve the reconstruction of the stacking pattern in carbonate slope successions both in outcrop and in subsurface settings.

The Lower Permian succession of the Central Southern Alps (Lombardy, Northern Italy) was deposited in fault-controlled continental basins, probably related to transtensional tectonics. We focussed our study on the stratigraphic record of the Lower Permian Orobic Basin, which consists of a 1000 m thick succession of prevailing continental clastics with intercalations of ignimbritic flows and tuffs (Pizzo del Diavolo Formation, PDV) resting on the underlying prevailing pyroclastic flows of the Cabianca Volcanite. The PDV consists of a lower part (composed of conglomerates passing laterally to sandstones and distally to silt and shales), a middle part (pelitic, with carbonates) and an upper part (alternating sandstone, silt and volcanic flows). Syndepositional tectonics during the deposition of the PDV is recorded by facies distribution, thickness changes and by the presence of deformation and liquefaction structures interpreted as seismites. Deformation is recorded by both ductile structures (ball-and-pillow, plastic intrusion, disturbed lamination, convolute stratification and slumps) and brittle structures (sand dykes and autoclastic breccias). Both the sedimentological features and the geodynamic setting of the depositional basin confidently support the interpretation of the described deformation features as related to seismic shocks. The most significant seismically-induced deformation is represented by a slumped horizon (about 4 m thick on average) which can be followed laterally for more than 5 km. The slumped bed consists of playa-lake deposits (alternating pelites and microbial carbonates, associated with mud cracks and vertebrate tracks). The lateral continuity and the evidence of deposition on a very low-angle surface along with the deformation/liquefaction of the sediments suggest that the slump was triggered by a high-magnitude earthquake. The stratigraphic distribution of the seismites allows us to identify time intervals of intense seismic activity, which correspond to rapid and basin-wide changes in the stratigraphical architecture of the depositional basin and/or to the reprise of the volcanic activity. The nature of the structures and their distribution suggest that the magnitude of the earthquakes responsible for the observed structures was likely higher than 5 (in order to produce sediment liquefaction) and probably reached intensity as high as 7 or more. The basin architecture suggests that the foci of these earthquakes were located close to the fault-controlled borders of the basin or within the basin itself.

The Norian in the Western Tethys is characterised by the deposition of early-dolomitised inner platform facies (Dolomia Principale/Hauptdolomit, DP/HD), bordered on the landward side by terrigenous coastal deposits (Keuper) and on the seaward side by calcareous backreef and reefal facies (Dachstein Limestone) passing basinward to open-sea sediments (Hallstatt facies). The inner carbonate platform is locally (Lombardy Basin, Carnic Alps, Central Austroalpine) dissected by normal faults leading to the development of intraplatform troughs. Close to the Norian–Rhaetian boundary, sedimentation records an abrupt environmental change both on platform top and basins all over the Western Tethys (e.g. Western Carpathians, Transdanubian Range, Alps, Central Apennine). The top of the Dolomia Principale locally emerged, reflecting a major eustatic sea-level fall. Emersion is recorded in favourable settings by the development of polycyclic paleosols up to 30 m thick. In the Norian intraplatform basins, the succession is capped by 4 to 8 m of thin-bedded, fine-grained limestones yielding abundant remnants of fishes and terrestrial reptiles. Fossil concentration as well as sedimentological features is indicative of reduced sedimentation rates due to decreased carbonate production, induced by the emersion of the platform top. The sea-level fall was followed by deposition of mixed fine-grained siliciclastic–carbonate successions (e.g. Riva di Solto Shale, Kossen beds, “ Rhaetavicula contorta beds”, Fatra Formation). Stratigraphic evidence indicates a dry climate in the Western Tethys during the Norian, as indicated by the presence of evaporites (Burano, Apennine) and arid to semi-arid coastal to playa settings (Upper Keuper, Germany). In contrast, the basal layers of the basinal shales show evidence of wet climate. The end of the Norian depositional system records two different phenomena: (1) an important sea-level fall was responsible for the emersion of the platform top and deposition of a condensed horizon in the basins; and (2) transition from dry to humid climate. The observed evolution is explained with a global cooling which caused the rapid sea-level fall responsible for the abrupt end of the DP/HD depositional system and the shift of the boundary between arid and temperate climate belts, which modified the distribution and amount of rainfall, triggering the deposition of shales along the Western Tethys margin.

The Triassic–Lower Jurassic succession of the Southern Alps is characterized by rapid thickness changes, from an average of about 5000 m east of Lago Maggiore to about 500 m in the Western Southern Alps. The stratigraphy reflects the Triassic evolution of the Tethyan Gulf and the Early Jurassic rifting responsible for the Middle Jurassic break-up of Adria from Europe. The succession of the Western Southern Alps starts with Lower Permian volcanics directly covered by Anisian sandstones. The top of the overlying Ladinian dolostones (300 m) records subaerial exposure and karstification. Locally (Gozzano), Upper Sinemurian sediments cover the Permian volcanics, documenting pre-Sinemurian erosion. New biostratigraphic data indicate a latest Pliensbachian–Toarcian age for the Jurassic synrift deposits that unconformably cover Ladinian or Sinemurian sediments. Therefore, in the Western Southern Alps, the major rifting stage that directly evolved into the opening of the Penninic Ocean began in the latest Pliensbachian–Toarcian. New data allowed us to refine the evolution of the two previously recognized Jurassic extensional events in the Southern Alps. The youngest extensional event (Western Southern Alps) occurred as tectonic activity decreased in the Lombardy Basin. During the Sinemurian the Gozzano high represents the western shoulder of a rift basin located to the east (Lombardy). This evolution documents a transition from diffuse early rifting (Late Hettangian–Sinemurian), controlled by older discontinuities, to rifting focused along a rift valley close to the Pliensbachian–Toarcian boundary. This younger rift bridges the gap between the Hettangian–Sinemurian diffuse rifting and the Callovian–Bathonian break-up. The late Pliensbachian–Toarcian rift, which eventually lead to continental break-up, is interpreted as the major extensional episode in the evolution of the passive margin of Adria. The transition from diffuse to focused extension in the Southern Alps is comparable to the evolution of the Central Austroalpine during the Early Jurassic and of the Central and Northern Atlantic margins.

New Late Ordovician and Triassic palaeomagnetic data from Iran are presented. These data, in conjunction with data from the literature, provide insights on the drift history of Iran as part of Cimmeria during the Ordovician-Triassic. A robust agreement of palaeomagnetic poles of Iran and West Gondwana is observed for the Late Ordovician-earliest Carboniferous, indicat- ing that Iran was part of Gondwana during that time. Data for the Late Permian-early Early Tri- assic indicate that Iran resided on subequatorial palaeolatitudes, clearly disengaged from the parental Gondwanan margin in the southern hemisphere. Since the late Early Triassic, Iran has been located in the northern hemisphere close to the Eurasian margin. This northward drift brought Iran to cover much of the Palaeotethys in approximately 35 Ma, at an average plate speed ofc. 7-8 cm year 21 , and was in part coeval to the transformation of Pangaea from an Irvin- gian B to a Wegenerian A-type configuration.

New structural, sedimentological, petrological and palaeomagnetic data collected in the region of Nakhlak-Anarak provide important constraints on the Cimmerian evolution of Central Iran. The Olenekian- Upper Ladinian succession of Nakhlak was deposited in a forearc setting, and records the exhumation and erosion of an orogenic wedge, possibly located in the present-day Anarak region. The Triassic succession was deformed after Ladinian times and shows south-vergent folds and thrusts unconformably covered by Upper Cretaceous limestones following the Late Jurassic Neo-Cimmerian deformation. Palaeomagnetic data obtained in the Olenekian succession suggest a palaeoposition of the region close to Eurasia at a latitude around 208N. In addition, the palaeopoles do not support large anticlockwise rotations around ver- tical axes for central Iran with respect to Eurasia since the Middle Triassic, as previously suggested. The Anarak Metamorphic Complex (AMC) includes blueschist-facies metabasites associated with discontinuous slivers of serpentinized ultramafic rocks and Carboniferous greenschist- facies 'Variscan' metamorphic rocks, including widespread metacarbonates. The AMC was formed, at least partially, in the Triassic. Its erosion is recorded by the Middle Triassic Baqoroq Formation at Nakhlak, which consists of conglomerates and sandstones rich in meta- morphic detritus. The AMC was repeatedly deformed during post-Triassic times, giving origin to a complex structural setting characterized by strong tectonic fragmentation of previously formed tectonic units. Based on these data, we suggest that the Nakhlak-Anarak units represent an arc-trench system developed during the Eo-Cimmerian orogenic cycle. Different tectonic scenarios that can account for the evolution of the region and for the occurrence of this orogenic wedge in its present position within Central Iran are critically discussed, as well as its relationships with a presumed 'Variscan' metamorphic event. The Cimmerian orogeny, affecting the southern Eurasian margin between Turkey and Thailand, is related to the collision of several microplates, most of which detached from northern Gondwana in the Early Permian during the opening of the

The Esino Limestone of the western Southern Alps represents a differentiated Ladinian-Lower Carnian (?) carbonate platform comprised of margin, slope and peritidal inner platform facies up to 1000 m thick. A major regional subaerial exposure event lead to coverage by another peritidal Lower Carnian carbonate platform (Breno Formation). Multiphase dolomitization affected the carbonate sediments. Petrographic examinations identified at least three main generations of dolomites (D1, D2, and D3) that occur as both replacement and fracture-filling cements. These phases have crystal-size ranges of 3–35 μm (dolomicrite D1), 40–600 μm (eu-to subhedral crystals D2), and 200 μm to 5 mm (cavity- and fracture-filling anhedral to subhedral saddle dolomite D3), respectively. The fabric retentive near-micritic grain size coupled with low mean Sr concentration (76 ± 37 ppm) and estimated δ18O of the parent dolomitizing fluids of D1 suggest formation in shallow burial setting at temperature ∼ 45–50 °C with possible contributions from volcanic-related fluids (basinal fluids circulated in volcaniclastics or related to volcanic activity), which is consistent with its abnormally high Fe (4438 ± 4393 ppm) and Mn (1219 ± 1418 ppm) contents. The larger crystal sizes, homogenization temperatures (D2, 108 ± 9 °C; D3, 111 ± 14 °C) of primary two-phase fluid inclusions, and calculated salinity estimates (D2, 23 ± 2 eq wt% NaCl; D3, 20 ± 4 eq wt% NaCl) of D2 and D3 suggest that they formed at later stages under mid-to deeper burial settings at higher temperatures from dolomitizing fluids of higher salinity, which is supported by higher estimated δ18O values of their parent dolomitizing fluids. This is also consistent with their high Fe (4462 ± 4888 ppm; and 1091 ± 1183 ppm, respectively) and Mn (556 ± 289 ppm and 1091 ± 1183 ppm) contents, and low Sr concentrations (53 ± 31 ppm and 57 ± 24 ppm, respectively). The similarity in shale-normalized (SN) REE patterns and Ce (Ce/Ce*)SN and La (Pr/Pr*)SN anomalies of the investigated carbonates support the genetic relationship between the dolomite generations and their calcite precursor. Positive Eu anomalies, coupled with fluid-inclusion gas ratios (N2/Ar, CO2/CH4, Ar/He), high F− concentration, high F/Cl and high Cl/Br molar ratios suggest an origin from diagenetic fluids circulated through volcanic rocks, which is consistent with the co-occurrence of volcaniclastic lenses in the investigated sequence.