56 research outputs found
The Early Miocene “Bisciaro volcaniclastic event” (northern Apennines, Italy): a key study for the geodynamic evolution of the central-western Mediterranean
The Early Miocene Bisciaro Fm., a marly limestone succession cropping out widely in the Umbria–Romagna–Marche Apennines, is characterized by a high amount of volcaniclastic content, characterizing this unit as a peculiar event of the Adria Plate margin. Because of this volcaniclastic event, also recognizable in different sectors of the central-western Mediterranean chains, this formation is proposed as a “marker” for the geodynamic evolution of the area. In the Bisciaro Fm., the volcaniclastic supply starts with the “Raffaello” bed (Earliest Aquitanian) that marks the base of the formation and ends in the lower portion of the Schlier Fm. (Late Burdigalian–Langhian p.p.). Forty-one studied successions allowed the recognition of three main petrofacies: (1) Pyroclastic Deposits (volcanic materials more than 90 %) including the sub-petrofacies 1A, Vitroclastic/crystallo-vitroclastic tuffs; 1B, Bentonitic deposits; and 1C, Ocraceous and blackish layers; (2) Resedimented Syn-Eruptive Volcanogenic Deposits (volcanic material 30–90 %) including the sub-petrofacies 2A, High-density volcanogenic turbidites; 2B, Low-density volcanogenic turbidites; 2C, Crystal-rich volcanogenic deposits; and 2D, Glauconitic-rich volcaniclastites; (3) Mixing of Volcaniclastic Sediments with Marine Deposits (volcanic material 5–30 %, mixed with marine sediments: marls, calcareous marls, and marly limestones). Coeval volcaniclastic deposits recognizable in different tectonic units of the Apennines, Maghrebian, and Betic Chains show petrofacies and chemical–geochemical features related to a similar calc-alkaline magmatism. The characterization of this event led to the hypothesis of a co-genetic relationship between volcanic activity centres (primary volcanic systems) and depositional basins (depositional processes) in the Early Miocene palaeogeographic and palaeotectonic evolution of the central-western Mediterranean region. The results support the proposal of a geodynamic model of this area that considers previously proposed interpretations.This research was supported by Urbino University funds (responsibles F. Guerrera and M. Tramontana); by CGL2011-30153-CO2-02 and CGL2012-32169 Research Project (Spanish Ministry of Education and Science); and by Research Groups and projects of the Generalitat Valenciana and Alicante University (CTMA-IGA)
Volcaniclastites as a key for geodynamic constraints in the evolution of the central-western Mediterranean region: an overview
In the central-western peri-Mediterranean chains, a consistent latest Chattian-Langhian orogenic calc-alkaline magmatism generated a high amount of volcaniclastites interbedded within penecontemporaneous marine successions. Emplacement of volcaniclastites is due mainly to epiclastic processes, implying paleogeographic constraints that instead do not control the distribution of fall-out pyroclastic deposits. Current knowledge does not allow direct correlations to be established between specific volcanic events and related secondary products; thus, reconstructions are based on field and analytic data. The volcanic activity occurred: (i) in the Adria Plate (during continental collision between the Mesomediterranean Microplate and the Adria-Africa Plate); (ii) along active subduction margins with different volcanic arc systems ("Mesomediterranean Microplate" Margin); (iii) back-arc basins (Apennine-Maghrebian-Betic systems; southwestern Corsica Margin and Sardinia Trough) due to rollback of the subductional slab; (iv) rifting (SE European Margin; e.g. Valencia and Provençal Basins) and (v) basins related to a strike-slip fault zone (Subbetic Basin). In this context it bears noting the scarcity at present of potential source areas consisting of primary products, suggesting that explosive volcanic arcs were quickly effaced during subduction. Instead, in rifting zones in the back arc areas the volcanic activity continues also in successive times and is testified to by several primary volcanic products. Paleogeographic and depositional constraints indicate multiple volcanic sources (arcs) located in different contexts but always near sedimentary basins. The study helps elucidate the evolution of interconnected geodynamic events in an original paleogeographic-paleotectonic framework.All this research was supported by Urbino University grants to F. Guerrera and M. Tramontana; CGL2012-32169 and CGL2016-75679-P research project (Spanish Ministry of Education and Science), by Research Groups and projects of the Generalitat Valenciana from Alicante University (CTMA-IGA)
Paleogene evolution of the External Betic Zone and geodynamic implications
Interdisciplinary studies combining field data (geological and tectonic mapping, lithostratigraphic reconstructions, lithofacies characterization, correlations and sampling) and laboratory analyses (biostratigraphy, chronostratigraphy, clay mineralogy and sandstone petrography) of eight Senonian-Paleogene successions from the Sierra de La Pila and Sierra de El Carche areas (Murcia province, SE Spain) belonging to the External Betic Zone are presented. Field evidence of tectonic activity (slumps, olistostromes, syn-genetic folds, lateral variability, changes in thicknesses, para- and unconformity boundaries, stratigraphic gaps, shallowing upward trends to emersion, etc.) was found in several Paleogene intervals. The results enable a better reconstruction of the stratigraphic architecture and chronostratigraphy of the Paleogene record, highlighting in particular: facies evolution, discontinuities, depositional sequences (Middle-Upper Maastrichtian, Upper Paleocene-Middle Eocene, Oligocene-Lower Aquitanian), environmental evolution (homogeneous conditions during the Late Cretaceous and successive realm diversification from platform to slope to basin) and correlations, along the Prebetic to Subbetic transition, which is a key sector to understand the northeastward variations of the South Iberian margin. A conclusive paleogeographic and geodynamic evolutionary model for the study area is proposed, hypothesizing that Paleogene compressive tectonics affected the eastern External Betic Zone. In addition, correlations with successions from the western External Betic Zone evidenced asynchronous deformation from east to west along the internalmost External Betic Zone. Moreover, a comparison with the external Tunisian Tell enables the recognition of similar sedimentarytectonic events, imposing new constraints in the Paleogene geodynamic reconstruction throughout the western Tethys.Research was supported by Urbino University found (responsible F. Guerrera), CGL2009-09249, CGL2011-30153-CO2-02 and CGL2012-32169 research projects (Spanish Ministry of Education and Science) and by Research Groups and projects of the Generalitat Valenciana from Alicante University (CTMA-IGA), and Junta de Andalucía (RNM-146)
Geological risk assessment of Amtoudi Agadir in southern Morocco: a key case for sustainable cultural heritage
Medieval fortified granaries known as “agadirs” are very common in southern Morocco, being catalogued as world cultural heritage by United Nations. These Berber buildings (made of stones and tree trunks) usually located on rocky promontories, constitute historical testimonials related to the origin of Morocco, and, as tourist attractions, have a positive impact on the local economy. The sustainability of these ancient monuments requires geological-risk evaluations of the massif stability under the agadir with the proposal of stabilization measures, and an architectonic analysis with appropriate maintenance of the structural elements. An interdisciplinary study including climate, seismicity, hydrology, geology, geomorphology, geotechnical surveys of the massif, and diagnosis of the degradation of structural elements have been performed on the Amtoudi Agadir, selected as a case study. The main findings from this study are that the prevalent rocks used for construction (coming from the underlying substratum) are good-quality arkosic sandstones; the SW cliffs under the agadir are unstable under water saturation; some masonry walls are too thin and lack interlocking stones and mortar; and failures in the beams (due to flexure, fracture, and exhaustion in the resistance due to insect attacks or plant roots) are common. The basic risk assessment of ancient buildings of cultural heritage and their geologic substratum are needed especially in undeveloped areas with limited capacity to implement durable conservation policies. Therefore, recommendations have been provided to ensure the stability and maintenance of this important archaeological site.This research was supported by Urbino University found (Resp. F. Guerrera); by CGL2011-30153-CO2-02 and CGL2012-32169 research project (Spanish Ministry of Education and Science); and by research groups and projects of the Generalitat Valenciana from Alicante University (CTMAIGA)
Miocene tectono-sedimentary evolution of the eastern external Betic Cordillera (Spain)
An interdisciplinary study of Miocene successions in the eastern External Betic Zone (South Iberian Margin) was carried out. Evidences of syn-sedimentary tectonic activity were recognized. The results enabled a better reconstruction of the stratigraphic architecture (with an improved chronostratigraphic resolution) in the framework of the Miocene foredeep evolution of the eastern EBZ. Two main depositional sequences were dated as uppermost Burdigalian-upper Serravallian p.p. and middle-upper Tortonian. p.p., respectively. The vertical and lateral diversification of lithofacies associations and thicknesses resulted from the syn-depositional tectonic complexity of the area. A great variety of sedimentary depositional realms is due to different subsidence rates, and the growing of anticlines and synclines during the Langhian p.p.-Serravallian. After a regression with an early Tortonian erosional gap, platform to hemipelagic realms developed during the middle Tortonian. The end of the sedimentation coincided with the emplacement of an important olisthostrome-like mass consisting of Triassic material related to either the development of thrust systems or diapirs emerged in the middle-late Tortonian, during the nappe emplacement. Correlations with other external sectors of the Betic Chain, and the external domains of the Rif, Tell, and northern Apennine Chains highlighted a similar Miocene foredeep evolution during the building of these orogens.CGL2016-75679-P; Research supported by Grants from Urbino University (Responsible M. Tramontana
Ceftolozane/Tazobactam for Treatment of Severe ESBL-Producing Enterobacterales Infections: A Multicenter Nationwide Clinical Experience (CEFTABUSE II Study)
Background. Few data are reported in the literature about the outcome of patients with severe extended-spectrum beta-lactamase-producing Enterobacterales (ESBL-E) infections treated with ceftolozane/tazobactam (C/T), in empiric or definitive therapy.Methods. A multicenter retrospective study was performed in Italy (June 2016-June 2019). Successful clinical outcome was defined as complete resolution of clinical signs/symptoms related to ESBL-E infection and lack of microbiological evidence of infection. The primary end point was to identify predictors of clinical failure of C/T therapy.Results. C/T treatment was documented in 153 patients: pneumonia was the most common diagnosis (n = 46, 30%), followed by 34 cases of complicated urinary tract infections (22.2%). Septic shock was observed in 42 (27.5%) patients. C/T was used as empiric therapy in 46 (30%) patients and as monotherapy in 127 (83%) patients. Favorable clinical outcome was observed in 128 (83.7%) patients; 25 patients were considered to have failed C/T therapy. Overall, 30-day mortality was reported for 15 (9.8%) patients. At multivariate analysis, Charlson comorbidity index >4 (odds ratio [OR], 2.3; 95% confidence interval [CI], 1.9-3.5; P = .02), septic shock (OR, 6.2; 95% CI, 3.8-7.9; P < .001), and continuous renal replacement therapy (OR, 3.1; 95% CI, 1.9-5.3; P = .001) were independently associated with clinical failure, whereas empiric therapy displaying in vitro activity (OR, 0.12; 95% CI, 0.01-0.34; P < .001) and adequate source control of infection (OR, 0.42; 95% CI, 0.14-0.55; P < .001) were associated with clinical success.Conclusions. Data show that C/T could be a valid option in empiric and/or targeted therapy in patients with severe infections caused by ESBL-producing Enterobacterales. Clinicians should be aware of the risk of clinical failure with standard-dose C/T therapy in septic patients receiving CRRT
Tracker Operation and Performance at the Magnet Test and Cosmic Challenge
During summer 2006 a fraction of the CMS silicon strip tracker was operated in a comprehensive slice test called the Magnet Test and Cosmic Challenge (MTCC). At the MTCC, cosmic rays detected in the muon chambers were used to trigger the readout of all CMS sub-detectors in the general data acquisition system and in the presence of the 4 T magnetic field produced by the CMS superconducting solenoid. This document describes the operation of the Tracker hardware and software prior, during and after data taking. The performance of the detector as resulting from the MTCC data analysis is also presented
Volcaniclastites as a key for geodynamic constraints in the evolution of the central-western Mediterranean Region: an overview.
In the central-western peri-Mediterranean chains, a consistent latest Chattian-Langhian orogenic calc-alkaline magmatism generated a high amount of volcaniclastites interbedded within penecontemporaneous marine successions. Emplacement of volcaniclastites is due mainly to epiclastic processes, implying paleogeographic constraints that instead do not control the distribution of fall-out pyroclastic deposits. Current knowledge does not allow direct correlations to be established between specific volcanic events and related secondary products; thus, reconstructions are based on field and analytic data. The volcanic activity occurred: (i) in the Adria Plate (during continental collision between the Mesomediterranean Microplate and the Adria-Africa Plate); (ii) along active subduction margins with different volcanic arc systems (“Mesomediterranean Microplate” Margin); (iii) back-arc basins (Apennine-Maghrebian-Betic systems; southwestern Corsica Margin and Sardinia Trough) due to rollback of the subductional slab; (iv) rifting (SE European Margin; e.g. Valencia and Provençal Basins) and (v) basins related to a strike-slip fault zone (Subbetic Basin). In this context it bears noting the scarcity at present of potential source areas consisting of primary products, suggesting that explosive volcanic arcs were quickly effaced during subduction. Instead, in rifting zones in the back arc areas the volcanic activity continues also in successive times and is testified to by several primary volcanic products. Paleogeographic and depositional constraints indicate multiple volcanic sources (arcs) located in different contexts but always near sedimentary basins. The study helps elucidate the evolution of interconnected geodynamic events in an original paleogeographic-paleotectonic framework
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