United States

More than 100 years after the devasting Messina-Reggio Calabria earthquake (M=7.1), the largest seismic event ever recorded in southern Europe in the instrumental epoch, its causative seismic source is still unknown, and the several rupture models proposed in the last decades are far from any shared solution. Data interpretation on a new dataset of sub-seafloor geophysical soundings with unprecedented resolution, relocated seismicity, and Vp model, together with morphotectonic investigations and inverse modelling of available levelling data, provide additional constraints on the deformation mechanisms and seismotectonics of the Strait of Messina area. High-resolution seismic lines in the offshore, along with displaced Quaternary marine terraces on land, point to active deformation along a previously unmapped ~ 34.5 km-long extensional fault. The spatial distribution of relocated earthquakes highlighted that a cut-off of the seismicity occurs within the crustal depth. The seismic discontinuity roughly delineates a foreland-dipping and low-angle discontinuity apparently confirming previous studies predicting low-angle seismogenic sources for the 1908 seismic event. However, according to the overburden stress and the attitude of the discontinuity, stress analysis suggests that a seismic slip is unlikely along it. This, therefore, weakens the hypothesis that a large earthquake may have nucleated along a low-angle discontinuity. Rather, aseismic creeping is instead expected since movement is allowed only by assuming a mechanical weakness of the plane. This mechanical behavior is currently also supported by the large interseismic strain-rate recorded in the area. Both seismic tomography and crustal-to-subcrustal scale 3D-modelling strongly suggest a cause-and-effect relationship between slab retreat, mantle wedging, uplift in the upper plate block, and active extension in the Strait of Messina area. Lithospheric doming of the upper plate is here interpreted to be the main process controlling uplift in the Peloritani Mts. of Sicily and subsidence in the Strait of Messina region where deformation is mainly accommodated by the weak low-angle discontinuity. In this frame, an almost aseismical slip toward the foreland of the low-angle discontinuity is here accounted to produce stress perturbation in the area. Coulomb stress change modelling revealed that simulated normal slip on the foreland-dipping discontinuity can induce additional stress and promote failure in the overlying brittle faults. An excellent fit between calculated and observed subsidence is achieved by geodetic data inversion that resolved a normal slip on the low-angle discontinuity and a transtensional (slightly left-lateral) motion on the 34.5 km-long and previously unknown extensional fault. The fault-length along with the observed seafloor displacement make this tectonic structure as the most likely to have produced large earthquakes in the Strait of Messina area.

SGI 2021

The Strait of Messina: Seismotectonics and the source of the 1908 earthquake

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L'Istituto Nazionale di Oceanografia e Geofisica Sperimentale - OGS e il Dipartimento di Matematica e Geoscienze dell'Università di Trieste sono orgogliosi di ospitare il 90° Congresso della Società Geologica Italiana a Trieste dal 14 al 16 settembre 2021. La modalità del congresso è interamente online.

Con il motto "Geologia senza frontiere" questo evento mira a promuovere le Scienze della Terra come disciplina scientifica proiettata nel futuro, oltre i confini geografici, politici e disciplinari, per comprendere meglio l'interno del Pianeta Terra e la struttura del sottosuolo, difendere la società da pericolosi eventi geologici, comprendere meglio la variabilità climatica, pianificare l'utilizzo delle georisorse in modo etico e nel rispetto dell'ambiente.


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The National Institute of Oceanography and Experimental Geophysics - OGS and the Department of Mathematics and Geosciences of the University of Trieste are proud to host the 90th Congress of the Italian Geological Society in Trieste on 14-16 September 2021.  The Congress will be held entirely online.

With the motto "Geology Without Borders" this event aims to promote Earth Sciences as a scientific discipline projected into the future, beyond geographical, political and disciplinary boundaries, to better understand the interior of Planet Earth and the structure of the subsurface, defend society from dangerous geological events, better understand climatic variability, plan the use of geo-resources in an ethical way and respecting the environment.


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technical paper

The ichnological survey of the track-bearing surface in the Pontrelli quarry (Altamura, Apulia) was performed using both traditional and new methodologies. Approximately 26,000 footprints were identified, 600 of which arranged in 12 quadrupedal trackways. Close-range photogrammetry was applied to gain accurate 3D models of the best-preserved specimens. The ichnological study, supported by morphometric analysis and photogrammetric models, led to the identification of different morphotypes, produced by two dinosaur trackmakers. In the Morphotype 1 are included the specimens characterised by tridactyl pes, which digits are lobe-shaped, and smaller manus (i.e., heteropody index between 1:5 and 1:2) with three subcircular pads. This ichnotaxonomical group includes the ichnospecies Apulosauripus federicianus, established by Nicosia et al. (2000) to describe the trackway ACDL99/3 . Nevertheless, numerous footprints can be also morphologically matched to the ichnogenus Caririchnium Leonardi, 1984. Six trackways can be assigned to this morphotype, including the two longest trackways of the ichnosite (represented by 75 and 88 manus-pes couples). The specimens of Morphotype 1 are referred to ornithopod dinosaurs, likely to medium-sized hadrosaurs with a hip height between 74 and 125 cm and up to 4.5 m long. The closest candidate is to date Tethyshadros insularis, 4-5 m long hadrosauroid from the upper Campanian-lower Maastrichtian deposits of Villaggio del Pescatore (Trieste, NE Italy). The Morphotype 2 is represented by a broad tetradactyl pes and a slightly smaller manus (i.e., heteropody index between 1:3 and 1:2 on average, in some specimens up to 1:1), in which four or five digits are barely recognizable. Six trackways are referable to this morphotype, among which the longest is constituted by 39 quadrupedal steps. The morphological features of these tracks closely match those of to the ichnogenus Tetrapodosaurus Sternberg, 1932, typically attributed to ankylosaurs. According primarily to the medium size of the ankylosaurian trackmaker of Altamura (hip height = 60-92 cm, body length = 2.5-4.5 m), the coincidence correlation method (Carrano & Wilson, 2001) suggests a nodosaurid as most suitable candidate, similar to the 2.5 m long Struthiosaurus or the 4 m long Hungarosaurus from the Santonian-Maastrichtian deposits of Europe. The occurrence of these two dinosaur groups in the Late Cretaceous of the Apulian Carbonate Platform can represent the keystone to enhance the knowledge on the palaeogeographic framework of the Periadriatic region.

The hadrosaur and nodosaur ichnoassemblage from the Altamura dinosaur tracksite (early Campanian; Apulia, southern Italy)

The Lavini di Marco ichnosite (Trentino-Alto Adige), discovered in 1989, is one of the most extensive European dinosaur tracksites, being the subject of several studies since early 90’s. The track-bearing layers are referred to the Monte Zugna Fm. (Hettangian-lower Sinemurian) of the Calcari Grigi Group, settled down within the palaeogeographic domain of the Trento carbonate Platform. In 2018, a new field survey was performed, as part of a joint project between MUSE - Science Museum of Trento, Sapienza University of Rome and Autonomous Province of Trento. The goal was to carry out an ichnological review and to realize the first geothematic map of the whole tracksite. During the survey both traditional and innovative methods were used, such as aerial and close-range photogrammetry. More than 700 tridactyl tracks and about 200 quadrupedal tracks were detected, and we mapped 27 trackways of both bipedal and quadrupedal dinosaurs. Close-range photogrammetry allowed to gain detailed morphological information, thus refining the ichnotaxonomical assignment. Morphological and morphometrical analyses allowed to assign most of the tridactyl tracks to the ichnogenus Kayentapus, although some specimens can be referred to the ichnogenera Anchisauripus, Grallator and Eubrontes. The occurrence of ornithischian ichnotaxon Anomoepus (previously hypothesized on the basis of two sub-parallel elongated tracks) was denied by the photogrammetric model, revealing the overlap of two tridactyl footprints with different size. The ichnotaxonomical review of quadrupedal trackways led to the emandation of the diagnosis of the ichnospecies Lavinipes cheminii and to assign several other sparse tracks and trackways to the same ichnotaxon. Panguraptor-like and Sinosaurus-like theropods have been identified as most suitable trackmakers for the tridactyl footprints, whereas the sauropodomorph Gongxianosaurus has been hypothesized as the most likely producer of Lavinipes cheminii. The occurrence of isolated tracks left by large theropods, which autopodium is still unknown in the skeletal fossil record, was also reported. The ichnoassemblage and the possible trackmakers thus suggest a palaeobiogeographic dispersal between Laurasia and the Trento Platform during the Hettangian, providing an accurate constraint to hypothesize their connection through northern and western sectors of Alpine region. Aerial photogrammetry was performed by using Unmanned Aerial Vehicles (i.e., drones) allowed to obtain orthophotos and orthoplanes of the whole tracksite. The map was realized in digital vector format with different level of knowledge with the aim of producing a comprehensive tool. The obtained geothematic map represents a complete documentation that will be useful for future work of enhancement, preservation and valorisation of the tracksite.

Geothematic map and ichnological review of dinosaur tracks from the Lavini di Marco ichnosite (Early Jurassic, Southern Alps, NE Italy)

In the Latina Valley (Central Apennines, Italy) several discontinuous bitumen outcrops and a well-known oil field occur, cultivated since the 19th century. The distribution of such deposits is strongly controlled by faults, which have a fundamental role in controlling hydrocarbon migration, entrapment, and/or leakage within fold-and thrust belts. However, little attention has been dedicated in the past to the role of post-orogenic normal faults in controlling hydrocarbon migration during the orogenic collapse. Field and subsurface data are here combined with geological evidence from the Ripi oil field, and a conceptual model is proposed for hydrocarbon migration along post-orogenic normal faults and entrapment within shallow reservoirs. Results show that post-orogenic normal faults promoted updip hydrocarbon migration from Upper Triassic mature source rocks, which generated oil during foreland/foredeep flexure and subsequent involvement into the accretionary wedge. Where pre-orogenic deposits were covered by less-permeable syn-orogenic sandstones, marls, and clays, hydrocarbons moved laterally from normal faults and impregnated high-porosity sandstone lenses, generating discontinuous and heavy oil reservoirs. On the contrary, where syn-orogenic deposits were eroded in response to orogenic uplift, hydrocarbons leaked at the Earth’s surface. Results from this study can be applied to reduce risks during hydrocarbon exploration and appraisal in similar tectonic settings.

The role of post-orogenic normal faulting in hydrocarbon migration in fold-and-thrust belts: insights from the Latina Valley (central Apennines, Italy)

Sclerobiont bryozoans have been found in the pelagic Maiolica Fm. of the Umbria-Marche Basin (Monte Acuto, Northern Apennines, Italy). The studied specimens, collected as loose material, are three sub-circular colonies of small size with tube-shaped zooecia, radially developing from the centre. Observable characters prevent generic or specific classification and only allow assignation to the Suborder Tubuliporina. Calpionellid assemblages constrain the bryozoan-bearing rock sample to the early Berriasian. This finding represents the first occurrence of isolated bryozoans in the Maiolica Fm., enriching our knowledge about the fauna of this stratigraphic unit in pure basinal settings. The fossil fauna of the unit in fact is commonly composed of radiolarians, calpionellids, dinoflagellate cysts and rare macrofossils (ammonites and aptychi), including only very rare benthic organisms (gastropods, brachiopods and bivalves). No sclerobiont organisms in ‘normal’ pelagic Maiolica facies were known up to date, due to the lack of suitable substrates to be colonised. Based on our material, encrustation of a planktonic or nektonic hard-shelled organism seems the most parsimonious hypothesis supporting this occurrence.

Sclerobiont Bryozoans from the Maiolica of the Umbria-Marche Domain (Northern Apennines, Italy)

This work provides the new geological-structural map of the southern Serre Massif (SM), an area extended for ~ 290 km2, located within the central sector of the Calabrian-Peloritani-Orogen (CPO). This segment of the CPO is characterized by the presence of a nearly entire Variscan crustal section, presently lying in a tilted position after the final stages of the tectonic uplift, associated with the later surficial stage of the Apennine stage of the Alpine orogeny. The map fits into this complicated geological-structural context with the aim to clarify the SM geodynamics. The new obtained geological map follows map design rules that aim to the concept of interoperability as one of the most important tasks of the modern cartography, useful to provide geologic maps more consistent in both appearance and database content. In the last years the interoperability concept and the geological data harmonization have become fundamental, with the statement of several new standards such as GeoSciML data model (www.geosciml.org). Therefore, standardization is now essential in the geoscience field because it allows to discuss and share the scientific data easier and faster (Ortolano et al., 2015). In the present work we used the esriNCGMP Online Geologic Mapping Template, a GIS-based solution that collects together cartography and data structures of the FGDC (Federal Geographic Data Committee), the Esri Geologic Mapping Template geodatabase schema and the NCGMP (National Cooperative Geologic Mapping Program) schema.  The use of this data models was essential to harmonize symbols and terminology that came from different original surveys and it focuses on two important aspects: the information about scientific confidence and locational accuracy of contacts and faults. and the information about data sources.  The “Scientific confidence” expresses a geologist level of certainty regarding the “identity” and “existence” of all features. The “identity” expresses if the observations and data support the nature, origin or geometry of a geologic feature. The “existence” expresses if the observations and data support the continuity or existence of a concealed or unseen geologic feature. Instead, the “Locational accuracy” is based on the relationship between a mapped feature location in the field and its position on the basemap. Therefore, the NCGMP data model clarifies these concepts providing appropriate terminology and symbol styles to adopt in each case.

Modern interoperability concepts applied to the new Geological Structural map of the Serre Massif Upper crust

The estimation of landslide hazard triggered by seismic events has been studied since 1965 through Newmark’s studied (Newmark, 1965). From the beginning up today, the mechanical approach to slope instability has been extended to GIS-based methods which are enable to consider the spatially distributed geomorphological and seismological variables strictly related this type of instabilities. Both predisposing and triggering variables are commonly combined by different methods (i.e. data driven, geostatistical, machine learning) to create maps at regional and urban scale. This latter scale is currently used worldwide for developing seismic microzonation of slope instabilities affecting urban areas threatened by high-magnitude earthquakes in several different geological contests. In the American continent, USGS collected in continuously updated web-GIS database informations about earthquake-induced landslides. It is the case of El Salvador, located in Central America, where the complex geodynamic is characterized by the interaction of four major tectonic plates and several microplates on their boundaries that cause high-magnitude seismic phenomena. Additionally, the lithostratigraphic and geomorphological characters (i.e. acid pyroclastites, volcanic ashes and pomices), are commonly affected by heavy rainfalls, so that hundreds of landslides are generated and consequently a huge number of casualties and economic losses. In this country, the Italian Agency for Development Cooperation (AICS) funded the CASTES project, which is devoted, among the numerous objectives of this international collaboration programme, to study unstable co-seismic effects induced within El Salvador territory. To this aim, a preliminary approach to define landslides hazard induced by the 2001 earthquake sequence has been applied. This latter consists of detecting the seismically-induced landslide inventory from aerial obtained after the two main shocks occurred on 13 January and 13 February 2001 (Mw 7.7 and 6.6, respectively). Then, the two magnitudes and landslides epicentral distances have been compared with the Keefer’s and Martino’s landslide triggering thresholds (Martino et al., 2014). These curves are useful in microzonation activities to estimate the possible occurrence of earthquake-induced landslides both in soils and rock formations related to all kind of kinematics. Nonetheless, according to the present authors’ knowledge, these curves have not been calibrated through volcanic geological territories, yet. Hence, this contribution is aimed at investigating the peculiar characters of the seismically-induced landslides in volcanic territories and to compare their triggering threshold to those ones identified worldwide.

Seismically-induced landslide estimation at regional scale in El Salvador volcanic territory

For centuries, the Plio-Pleistocene deposits of Tuscany (central Italy) have been the location of prime discoveries of fossil vertebrates. Though such finds have significantly contributed to international vertebrate palaeontology, many of these historical finds lack precise stratigraphic whereabouts; furthermore, correlations between continental and marine assemblages have always been difficult, thus hampering integrative palaeoecological reconstructions. Here, we provide a preliminary characterization of the vertebrate assemblage from La Serra quarry (Pisa Province, Tuscany), were the exposed Pliocene sediments are arranged into a transgressive-regressive cycle that testifies to coastal marshes, deltaic-estuarine environments, semi-protected lagoons and shoreface settings. The vertebrate assemblage from these deposits features some fifteen species of mammals, reptiles and fishes. Mammals are mostly represented by isolated remains referable both to juvenile and adult individuals of Proboscidae indet., a small-sized Cervinae, a large-sized Cervidae, and Sus cf. S. arvernensis. The proboscideans are represented by large-size vertebrae and ribs. Cervidae are documented by isolated teeth and some postcrania that resemble the late Ruscinian Cervinae. The suid is represented by a juvenile specimen, smaller than Sus strozzii and Propotamochoerus provincialis, and closer to the relatively small-size suid from the Baccinello V3 fauna. The fish remains include dental and dermal elements of Carcharhinus cf. perezi, Carcharias taurus, Carcharodon carcharias, Galeocerdo cuvier, Myliobatis sp., Dasyatidae? Indet. (including the longest tail spine ever reported from the fossil and Recent records), Sparidae indet., and Tetraodontidae indet. The turtles are represented by a cervical vertebra of Chelonioidea indet. as well as by plastral and carapacial elements of Mauremys sp. and Testudo sensu lato. By including terrestrial, freshwater, and marine forms, the vertebrate assemblage from La Serra represents an ideal scenario for providing a synoptic glimpse into a Pliocene paralic ecosystem of Tuscany, as well as for elaborating novel correlations between terrestrial, freshwater and marine vertebrate assemblages.

Living along a Pliocene Tuscan coast: terrestrial, freshwater and marine vertebrates from La Serra quarry (Tuscany)

Lower Cretaceous carbonate platforms record distinctive facies in the area of Getic unit defined Beriasian, Valanginian, Hauterivian and Urgonian like facies. These deposits result from the continuous trend of shallow-water sedimentation that started in the Middle Jurassic time. Recent studies on the Getic carbonate platform succession focused on outcrops in Romania and Bulgaria, whereas detailed investigation on the Serbian side of the Getic platform was limited to solving biostratigraphy, paleontology and facies distribution issues on local scale, mostly in northeastern Serbia. The most exhaustive research on the Getic platform in southern and central Serbia dates back to the 70s of last century (Jankičević, 1978). The study area is located in the Carpatho-Balkanides of Serbia, close to the town of Dimitrovgrad, and includes the narrow belt of Lower Cretaceous (Valanginian-Hauterivian) carbonate successions in the southern sector of the Getic Carbonate Platform. The identified carbonate facies consist of foraminifera mudstone to wackestone, bioclastic wackestone, (fenestral) peloidal grainstone, skeletal packstone and mixed siliciclastic sediments (sandstone) indicative of different environments from shallow platform interior to slope and basin. The data from Dimitrovgrad locality with beds fully made of Bacinella sp. show the significant changes in environment of deposition from platform interior to reef depositional environment. Besides that, the pyrite rich siliciclastics provide the information of transition to slope environment. The distribution of different facies show rapid lateral and vertical changes of depositional environments varying from platform interior to reef and finally to the slope and basin conditions.

New data from the Lower Cretaceous carbonate platform deposits of Dimitrovgrad section (Southeastern Serbia)

The Monte Amiata volcano is located in southern Tuscany, at the geographical overlap of the Tuscan magmatic province with the Roman magmatic province. It is a small Pleistocenic volcano made up prevalently by viscous lava flows and domes ranging in composition from trachydacites to olivine latites. The volcanic rocks emplaced in a very short period of time, between 305 and 231 ka (Laurenzi et al., 2015). Lava flows and domes are grouped into three main complexes, one for each stage of activity: the “Basal Trachydacitic Complex” (BTC), the “Dome and Lava flow Complex” (DLC) and the  “Olivine Latite  final lavas” (OLF;  Conticelli  et al.,  2015;  Marroni  et al., 2015). The most important petrographic characteristics of Monte Amiata volcanic rocks are represented by: i) the occurrence of sanidine megacrysts, mostly confined in the rocks emplaced in concomitance with the second stage of the Monte Amiata volcanic activity (DLC); ii) the occurrence of rounded fine-grained mafic enclaves with cuspidate margins convex toward the host, which constitute proof of the mingling process that took place at Monte Amiata and that possibly triggered the eruptions of these highly viscous magmas; iii) the occurrence of mafic olivine latitic lava flows, emplaced as the final product of the volcanic activity and characterised by an intermediate composition between the early silica-rich volcanic rocks and the most mafic enclaves hosted by Monte Amiata volcanic rocks. Here, we present the preliminary results about the origin, the evolution, and the distribution of the mafic enclaves hosted by the Monte Amiata lavas and domes. To do this, thin sections were studied under the petrographic microscope, chemical analyses of whole rocks and enclaves and their rock-forming minerals were carried out. A statistical survey on the magmatic enclaves distribution and their size variations was also made. These preliminary results suggest that Monte Amiata mafic enclaves change in composition and increase in size and abundance from those hosted by domes and lavas with the highest silica contents to those hosted by domes and lavas with the lowest silica contents.

Study of the origin, the evolution, and the distribution of Monte Amiata mafic enclaves

The Early Cretaceous ammonite fauna is well-known from several localities in Central Serbia. Discovered Lower Cretaceous sediments extend in the narrow belt Belgrade-Kosmaj-Topola-Gledić Mts. (Anđelković, 1954). The wide study area belongs to the: Eastern Vardar Ophiolitic Unit (Schmid et al., 2008), Main Vardar Zone (Karamata, 2006) or Northern part of Central Vardar Subzone (Dimitrijević, 1997). Newly collected ammonite assemblages described herein came from Kotraža section located SW of Topola in Šumadija District. In Serbian geological literature, the oldest Cretaceous sediments of this area are described as Barremian-Aptian shallow-marine limestones, which are overlying younger Upper Albian glauconitic sandstones, marls and marly sandstones (Anđelković, 1954). The Upper Albian sediments of Kotraža section profile are represented by 11 m thick glauconitic sandstones and marly sandstones bearing rich fauna of ammonites, belemnites, gastropods and plant tissues. These sediments yielded a rich ammonite fauna that includes representatives of three superfamilies of Phylloceratoidea, Tetragonitoidea and Desmoceratoidea. The lower and middle part of the profile is dominated by 8 m thick glauconitic sandstones and reddish Fe-rich sandstones from which some ammonite taxa are isolated: Anisoceras sp., Mortoniceras sp., Phylloceras (Hypophylloceras) velledae and Puzosia mayoriana. The uppermost part of the profile, consists of 3 m thick sandy marls and marly sandstones with dominant fauna of genus Puzosia and other species: Kossmatella agassiziana and Puzosia (Puzosia) mayoriana. The studied deposits with ammonite assemblages belongs to the lower part of the Mortoniceras perinflatum Zone (sensu Reboulet et al., 2018).

The Strait of Messina: Seismotectonics and the source of the 1908 earthquake

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The hadrosaur and nodosaur ichnoassemblage from the Altamura dinosaur tracksite (early Campanian; Apulia, southern Italy)

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The Strait of Messina: Seismotectonics and the source of the 1908 earthquake

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The hadrosaur and nodosaur ichnoassemblage from the Altamura dinosaur tracksite (early Campanian; Apulia, southern Italy)

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Database of active faults in Friuli Venezia Giulia: a basic tool for seismic hazard assessment

Stay up to date with the latest Underline news!

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