Italian Journal of Geosciences最新文献

{"title":"Frost action and human occupation during the Late Pleistocene in the Italian Southern Alps: micromorphological evidences from the Caverna Generosa cave","authors":"Eleonora Sessa, F. Bona, L. Angiolini","doi":"10.3301/ijg.2020.28","DOIUrl":"https://doi.org/10.3301/ijg.2020.28","url":null,"abstract":"The Late Pleistocene has been characterised by frequent and intense climatic oscillation, well recorded in the Caverna Generosa cave deposits. In this work, micromorphological analyses have been performed on samples from the cave where the stratigraphy is particularly well exposed and complete, in order to obtain temporal and spatial information on climate- and human-related processes during MIS3 and 4. The older layers (more than 50 ka BP - Before Present - old) record a very cold time interval, where ice did not melt during the warmer season, and with little or no vegetation outside the cave. During this cold stage, probably, humans spent a short period in the cave, using bones to light the fire and, later, cave bears dug their hibernation beds in the innermost room. Subsequently (between 50 ka BP and 40 ka BP) a relatively brief climatic amelioration should have occurred, leading to the onset of ice melting during the summer season. Between 40 ka BP and 30 ka BP, loess deposited in the cave entrance, indicating cold and arid conditions in the area. After loess deposition, recovered wet conditions have re-established with freeze and thawing processes influencing the sediments.","PeriodicalId":49317,"journal":{"name":"Italian Journal of Geosciences","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2021-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41582975","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"150 years of plans, geological survey and drilling for the Fréjus to Mont Blanc tunnels across the Alpine chain: an historical review","authors":"G. D. Piaz, A. Argentieri","doi":"10.3301/ijg.2020.29","DOIUrl":"https://doi.org/10.3301/ijg.2020.29","url":null,"abstract":"Since Roman age, people living on both sides of the Alps had been seeking different ‘north-west passages’, first overriding the mountains and then moving under them. The first idea of a tunnel under the Mont Blanc was envisaged by de Saussure in 1787. In the 19th century a growing railway network played a fundamental role for the Industrial Revolution, but was hampered for the southern countries by the barrier of the Alps, so that modern transalpine railways became essential for the Reign of Sardinia. This paper presents an historical review of first suggestions, projects, field survey, failed attempts and successful drilling works across the Alps, from the Frejus (1871), San Gottardo (1882) and Simplon (1906) railway tunnels to the Grand St Bernard (1964) and Mont Blanc (1965) highway tunnels, relived within the advances of regional geology and mapping. The Frejus tunnel was conceived by Medal, projected by Maus between Modane and Bardoneche and approved by a ministerial commission, but it was abandoned due to the insurrection of 1848. Later, it was taken up again, developed by Sommeiller, promoted by Cavour himself, and approved in 1857. Technical management was assigned to Sommeiller, Grattoni and Grandis. Frejus was the first, longest and innovating railway tunnel in the world: drilling began in 1857 and ended in December 1870, thanks to a new drilling machine powered by compressed-air. Its inauguration took place on September 1871. When the Frejus drilling was still in progress, John Fell built a mountain railway between Piedmont and Savoy, through the Mont Cenis, following the Napoleonic road. During its four years of work (1868- 1871) it managed to transport about 100,000 travellers, but it was forced to close down when the Frejus railway tunnel was opened. The geological advances and mapping in the Western Alps by the mid-19th century provided information and reliable tools for better planning of great engineering works, but tunnel designs were not always based on a geological survey: the main exceptions were represented by GiorDano (Gottardo, 1881) and Baretti (Mont Blanc, 1880). The former tunnel was drilled, the latter was not accomplished, as other projects were instead preferred across the Western Alps, Colle di Tenda (1898) and then Simplon (1906). After new hopes, the geological study on four project tunnels under the Mont Blanc by Franchi, Kilian and Jacob (Franchi et alii, 1908), and further disappointments, decisive moves to achieve the underground connection between Courmayeur and Chamonix were made by Dino Lora Totino who requested a project to Vittorio Zignoli. Meanwhile, a geological survey for radioactive minerals was promoted by CNRN on the Italian side of the Mont Blanc: field work was performed by Baggio and his staff, and their best result was the discovery of mylonitic-cataclastic shear zones crossing the tunnel route. Their work continued during the drilling inside the Italian part of the Mont Blanc motorway tunnel, s","PeriodicalId":49317,"journal":{"name":"Italian Journal of Geosciences","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2021-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47200127","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mineralogical and petrographic study of building materials from the Argentario coastal towers (Tuscan, Italy): anthropic evidence of the ancient landscape","authors":"E. Cantisani, F. Fratini, S. Vettori, E. Pecchioni, L. Chelazzi, A. Arrighetti","doi":"10.3301/ijg.2020.27","DOIUrl":"https://doi.org/10.3301/ijg.2020.27","url":null,"abstract":"The coastal sight towers and the defensive fortresses were in the past distinctive elements of the coastal landscape. They were distributed in particular along the northern coast of the Mediterranean and were built for sighting purposes from the XVIth century against the raids of barbarian pirates who had their bases in the Maghreb coast.A mineralogical and petrographic characterization of the stone materials and mortars of two coastal towers (i.e. Capodomo and Calamoresca) in ruins of Monte Argentario is shown in the present paper. It was found that local lithotypes (e.g. Calcare Cavernoso, calcitic grey marble, dark grey dolostones) were used as building stones and for production of mortars. A detailed study on mortars was conducted by means of high quality polycrystalline X-ray diffraction, optical and electron microscopy. The analysis reveals the presence of Ca and Mg lime-based mortars in the ruins of Capodomo tower, whereas only Ca lime-based mortars were identified in Calamoresca tower.Reaching the towers walking along the paths allows us to know a good part of the lithologies present in the promontory due to the emerging sites in the local morphology; emersion was produced, both because particular lithologies are resistant to the erosion and also because of particular structural or tectonic elements.","PeriodicalId":49317,"journal":{"name":"Italian Journal of Geosciences","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2021-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46362588","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Roccacaramanico Conglomerate (Maiella Tectonic Unit) in the frame of the Abruzzo early Pliocene Foreland Basin System: stratigraphic and structural implications","authors":"F. Brozzetti, Francesca Cerritelli, D. Cirillo, S. Agostini, G. Lavecchia","doi":"10.3301/ijg.2020.04","DOIUrl":"https://doi.org/10.3301/ijg.2020.04","url":null,"abstract":"In the upper Tertiary succession of the Maiella Tectonic Unit (Abruzzo, Italy), coarse calciclastic layers, hereinafter referred to as Roccacaramanico Conglomerate (RCC), were deposited during a short time span which approximates the Miocene-Pliocene boundary. The biostratigraphic characterization of RCC is well constrained by previous studies of foraminifer and nannofossil assemblages. In fact the pelitic interbeds of the RCC are attributed to the Sphaeroidinellopsis spp. Biozone and to the MNN12 Nannofossil Zone belonging to the earliest Pliocene.Previous works referred this conglomerate to Apennine- fed sediment gravity-flows however, in the absence of detailed compositional data and of a regional-scale sedimentological study of the layers, only generic hypotheses on the source-area and on the nature of the event which triggered the RCC deposition, were formulated.Here we present the results of an original investigation on the RCC cropping out within the Maiella Tectonic Unit, in the area delimited westward by the Morrone-Porrara thrust and, towards south-east, by the Molise allochthonous Units.In this area, a fairly continuous RCC horizon, exposed on both limbs of the Maiella anticline, was mapped and logged in detail. Our lithostratigraphic analysis allowed to make hypotheses on depositional mechanisms of RCC and revealed that it consists of several (six to ten) major depositional events producing locally amalgamated pluri- metric clastic layers.Our facies analysis highlighted that previous studies had generally underestimated the overall thickness of the layers and that in the southernmost examined outcrops (Palena, Taranta Peligna and Lama dei Peligni), the RCC is characterized by higher thickness, coarser grain-size, poorer sorting and more pronounced channeling compared to that cropping out in northernmost areas (Roccacaramanico, San Nicolao and San Valentino). The recognition of facies-types characterized by greater proximality in the southern Maiella area, and the overall geometric reconstruction of the depositional architecture of the RCC horizon, suggests that, contrary to what was previously assumed, the major sediment gravity-flows were fed from the south-eastern edge of the basin. This result is also confirmed by the paleocurrent data, testifying northward flowing currents directed SSE-NNW.The compositional analysis of RCC, highlighted an almost totally calcareous composition of the clasts and a poor and scattered siliciclastic fraction, mainly occurring as fine grained matrix. Clasts showing inner platform, bio-constructed margin, ramp, transitional and basinal facies, of different ages, are mixed throughout the layers. Nevertheless, these data allowed us to make inferences on the provenance of the sediment supply and on the stratigraphic successions that were undergoing erosion in the area surrounding the basin, around the Messinian-Pliocene boundary.A quantitative assessment of the RCC volume was finally achieved, taking into a","PeriodicalId":49317,"journal":{"name":"Italian Journal of Geosciences","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2020-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3301/ijg.2020.04","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69480281","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"An outline of the geology of the Northern Apennines (Italy), with geological map at 1:250,000 scale","authors":"P. Conti, G. Cornamusini, L. Carmignani","doi":"10.3301/IJG.2019.25","DOIUrl":"https://doi.org/10.3301/IJG.2019.25","url":null,"abstract":"An outline of the geology of the Italian Northern Apennines, to accompany a geological map at 1:250,000 scale covering the Emilia- Romagna, Marche, Tuscany and Umbria regions, is presented herein. The map is intended as a first result of a longer term project carried out by the Geological Surveys of the above regions, aimed to create a common geological map at 1:10,000 scale, useful for environmental planning and management.The lithostratigraphic units are grouped in domains and successions (with references to main tectonic units), and a special effort was made to correlate similar lithostratigraphic units across the area. The enclosed geological map distinguishes stratigraphic successions deposited in: a) Ligurian Domain (Internal and External Ligurian domains); b) Subligurian Domain; c) Tuscan Domain (Tuscan Succession, Tuscan Metamorphic Succession, Cervarola- Falterona Succession, Modino Succession, Rentella Succession, Pseudoverrucano Succession); Umbria-Marche-Romagna Domain. Tectonic units derived from regional tectonic melanges and shear zones (Sestola-Vidiciatico Unit), and units affected by HP metamorphism in the Tuscan Archipelago and southern Tuscany have been mapped. Distinguished younger successions are: a) Epiligurian Succession; b) Miocene-Pleistocene succession of the Tyrrhenian margin; c) Miocene- Pleistocene succession of the Po Plain and Adriatic margin. The main outcrops of magmatic rocks (Miocene-Pleistocene in age) and Quaternary alluvial, continental and coastal deposits have also been mapped. Main tectonic contacts (high-angle normal faults, main thrust and low-angle normal faults) are indicated. The 1:250,000 geological map of the Northern Apennines is freely available as PDF, raster and vector GIS data from the web site: https://www.geological-map.it.","PeriodicalId":49317,"journal":{"name":"Italian Journal of Geosciences","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2020-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3301/IJG.2019.25","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46742440","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A multidisciplinary approach for physical landscape analysis: scientific value and risk of degradation of outstanding landforms in the glacial plateau of the Loana Valley (Central-Western Italian Alps)","authors":"I. Bollati, B. C. Lenz, V. Caironi","doi":"10.3301/ijg.2020.01","DOIUrl":"https://doi.org/10.3301/ijg.2020.01","url":null,"abstract":"Landforms characterized by high scientific value (i.e. geomorphosites) might undergo modifications due to intrinsic and extrinsic factors (natural and human-induced processes). In the framework of geoheritage analyses, the assessment of the value (scientific or additional) of geomorphosites should be performed side by side with the analysis on the risk of degradation (fragility and vulnerability). A multidisciplinary method is proposed for the analysis of landforms that are potentially fragile but outstanding for their scientific value related to geological, geomorphological and ecological values. A geomorphological map was produced for the glacial plateaux of the Loana Valley (Central-Western Italian Alps), where an outstanding geomorphosite was detected: the Cortenuovo Calcareous Ridge. The site is herein analysed in terms of the representativeness of geological and (paleo)geomorphological features as well as for its support role to the ecosystem. For dissemination purposes, a simplified version of the geomorphological map (i.e., geomorphological box) was prepared for the site. Specific morphometric and dendrogeomorphological analyses were then performed to investigate more in detail the risk of degradation of the site. It resulted to be a spatially restricted hotspot of geodiversity, characterized by an average surface lowering rate (0.44 cm/y on average) comparable to that achieved in similar geomorphologic contexts in the Alpine environment. The obtained results testify to a potential vulnerability to natural processes of this highly scientific valued site, which will surely benefit from a legal recognition as a component of geoheritage, with a specific regulation for its protection, that could prove to be strategic.","PeriodicalId":49317,"journal":{"name":"Italian Journal of Geosciences","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2020-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3301/ijg.2020.01","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45967887","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Tetrapod tracks from the Middle Triassic of NW Sardinia (Nurra region, Italy)","authors":"P. Citton, A. Ronchi, U. Nicosia, Eva Sacchi, S. Maganuco, A. Cipriani, Giulia Innamorati, C. Zuccari, Fabio Manucci, M. Romano","doi":"10.3301/ijg.2020.07","DOIUrl":"https://doi.org/10.3301/ijg.2020.07","url":null,"abstract":"We report here on the first tetrapod tracks from the Triassic of the Nurra region (north-western Sardinia, Italy). The specimens were found on sandstone blocks used to build a fence limiting a seasonal camping, in the coastal area north of Capo Caccia promontory. Lithologic and petrographic features allowed an assignment of the track-bearing blocks to the middle-upper portion of the Anisian (Middle Triassic) Arenarie di Cala Viola (Buntsandstein). Footprints are attributed to the ichnotaxa Rhynchosauroides and Rotodactylus, two common ichnotaxa of late Early Triassic and Middle Triassic ichnofaunas of Europe and United States, commonly referred in the literature to neodiapsid and archosaur producers, respectively.","PeriodicalId":49317,"journal":{"name":"Italian Journal of Geosciences","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2020-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3301/ijg.2020.07","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42172771","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"U-Pb ages on detrital zircons and geochemistry of Lula paragneiss from Variscan belt, NE Sardinia, Italy: implications for source rocks and early Paleozoic paleogeography","authors":"G. Cruciani, M. Franceschelli, V. Caironi, G. Musumeci","doi":"10.3301/ijg.2019.24","DOIUrl":"https://doi.org/10.3301/ijg.2019.24","url":null,"abstract":"Chemical analyses of garnet-bearing metasediments and EMP and U/Pb analyses of detrital zircons of the Lula paragneisses in the Axial Zone of the Variscan belt (NE Sardinia) give significant contribution to the reconstruction of the early Paleozoic evolution of the northern Gondwana margin. The youngest middle Ordovician (465 Ma) age of detrital zircons indicate a derivation from a fore- arc sedimentary basin along an early Paleozoic convergent margin, which collected sediments from nearby emerged lands consisting of early Paleozoic volcanic arcs and pre-Paleozoic sequences. The chemical composition of metasediments is characterized by negative Sr anomaly and depletion in heavy rare earth elements (HREE) and Y as compared to the upper crust. Normalized to chondrite values, the paragneiss shows a steep REE pattern with light-REE enrichment, negative Eu anomaly and flat heavy-REE pattern. All these features suggest a derivation form older active continental margins or island arcs. Detrital zircon ages cover a very large time span (3151 + 97 Ma to 465 + 8 Ma) and reveal a complex history of inheritance and recycling. The oldest ages obtained on relic cores and/or magmatic stages, mostly enriched in Hf (Zr / Hf ratios: 45-24) and devoid of Y, indicate a contribution from granitoid rocks of mainly crustal origin. The ages of detrital zircons highlight a derivation of the sedimentary supply from the Sahara craton and/or the Arabian-Numidian shield along the northeastern margin of Gondwana. This fit well with derivation of early Paleozoic metasedimentary formations in southern Sardinia and northern Apennine, pointing out a common origin and location of these sedimentary basins along the northern margin of Gondwana at the early Paleozoic. As regards the Variscan orogeny, the common middle Ordovician age of Lula paragneiss and nearby Lode orthogneiss highlight the role of Variscan tectonics in the assembly of different blocks of early-middle Paleozoic margin.","PeriodicalId":49317,"journal":{"name":"Italian Journal of Geosciences","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2020-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44825001","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Stratigraphic and structural reconstruction of an offshore sector of the Hyblean Foreland ramp (southern Italy)","authors":"S. Distefano, F. Gamberi, A. Stefano","doi":"10.3301/IJG.2019.12","DOIUrl":"https://doi.org/10.3301/IJG.2019.12","url":null,"abstract":"Through the seismo-stratigraphic analysis of new high- resolution seismic data acquired along the southwestern offshore of the Hyblean Plateau, this work aims to improve the knowledge about the stratigraphic and structural setting in the marine area connecting the Hyblean Plateau Foreland to the Gela-Catania Foredeep.Two main goals have motivated the acquisition of new seismic profiles along the southern coastline of Sicily, in the Marina di Ragusa offshore:(i) to obtain a better comprehension of the Cenozoic stratigraphic and structural setting of the area, with a particular attention to the characterization of the Pliocene-Holocene sedimentary deposits and their areal distribution;(ii) to identify, in the offshore area, the possible prolongation of the main structural lineaments outcropping in the hinterland (Scicli-Ragusa-Irminio Line), and verify the presence of structures, responsible for the tectonic activity affecting the area.Our model shows that an extensional fault system, characterized by a main NE-SW orientation, affects the highly deformed Oligo-Miocene, or older, substratum, originating structural highs and down-faulted sectors. These faults are inferred to record the early history of the Scicli Line and of the polyphase kinematic evolution of the N50° oriented regional fault systems.The Gessoso-Solfifera deposits (Messinian, Late Miocene) have been recognized in several sectors of the study area, showing a very peculiar seismic facies, and occupying deep erosional channels probably resting within down-faulted sectors. This feature is in good agreement with isolated onshore areas of the Hyblean Plateau (Licodia Eubea and south Vittoria villages) where the Gessoso-Solfifera deposits are associated to normal faults, thus documenting that Messinian evaporites are not restricted to compressive tectonic setting, such as the marginal sub-basins and the thrust top mini-basins of the Appennine-Maghrebian belt.A peculiar seismic facies has been associated to the Trubi Fm., unconformably lying upon the older succession.The undeformed seismic units, onlapping the older substratum, has been associated to the post-Trubi-Holocene deposits, arranged into seven seismic units that reflect the youngest depositional evolution of the nearby Catania-Gela Foredeep. These deposits, generally represented by plane-parallel seismic facies, are in turn separated by an unconformity highlighted by an onlap termination of the yougermost terms upon the older. In some cases they are interrupted by gas rising from the deeper succession that reaches, at times, also the seafloor.","PeriodicalId":49317,"journal":{"name":"Italian Journal of Geosciences","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2019-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3301/IJG.2019.12","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46106580","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Neogene volcanism in Elazig-Tunceli area (eastern Anatolia): geochronological and petrological constraints","authors":"S. Agostini, M. Y. Savaşçın, P. D. Giuseppe, Flavio Di Stefano, Ö. Karaoǧlu, M. Lustrino, P. Manetti, Y. Ersoy, S. Kürüm, A. Önal","doi":"10.3301/IJG.2019.18","DOIUrl":"https://doi.org/10.3301/IJG.2019.18","url":null,"abstract":"The Elazig and Tunceli provinces in eastern Anatolia host a complex succession of Miocene-Pleistocene effusive and explosive volcanic rocks, divided into four distinct volcanic phases. The most abundant and widespread products are the calcalkaline Mazgirt volcanic rocks, characterized by wide Sr isotope variations (87Sr/86Sr ~0.7054-0.7077) and narrower 143Nd/144Nd (~0.51246-0.51260) and Pb isotopes (e.g., 206Pb/204Pb ~18.89-19.13). New 40Ar-39Ar ages indicate that Mazgirt volcanic activity occurred between ~16.3 and 15.1 Ma. The other three volcanic phases are represented by the Tunceli mildly alkaline basaltic lavas (~11.4-11.0 Ma), the Pliocene Karakocan (~4.1 Ma) and Pleistocene Elazig (~1.9-1.6 Ma) Na-alkali basaltic lavas with clear OIB-like geochemical signature.Mazgirt volcanics can be subdivided on the base of mode of emplacement into lava flows and lava domes units characterized by petrographic, chemical and isotopic differences: lava flows are calcalkaline, whereas lava domes mostly belong to a high-K calcalkaline series and are, on average, more LREE- and 87Sr-enriched. Lava domes are more porphyritic, with a phenocryst assemblage dominated by amphibole, whereas plagioclase and clinopyroxene are the most abundant phenocryst phases in lava flows, pointing out that evolution of dome magmas occurred in conditions of slightly higher pressure, favouring the crystallization of hydrous phases.The Karabakir Formation, previously reported as late Miocene- Pliocene, encloses Mazgirt volcanics and is capped by Tunceli basalts. These new age data constrain the Karabakir Formation emplacement from early to late Miocene.The evolution of this igneous activity mirrors the geodynamic framework of the region: the early-middle Miocene Mazgirt volcanics represent arc volcanism related to Eurasia-Arabia convergence. The late Miocene Tunceli basalts postdate the onset of post-collisional tectonics in Eastern Anatolia, whereas the Karakocan and Elazig volcanic rocks were emplaced after the initiation of strike-slip motion on the North Anatolian and East Anatolian Fault systems.","PeriodicalId":49317,"journal":{"name":"Italian Journal of Geosciences","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2019-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3301/IJG.2019.18","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48873658","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}