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The use of mineral interfaces in sand-sized volcanic rock fragments to infer mechanical durability

Journal of Palaeogeography 2020年第3期9卷 288-313页

作者： Emilia Le Pera Consuele Morrone dipartimento di Biologia Ecologia e Scienze della Terra(DiBEST)Universita

The use of mineral interfaces, in sand-sized rock fragments, to infer the influence exerted by mechanical durability on the generation of siliciclastic sediments, has been determined for plutoniclastic sand. Conversely, for volcaniclastic sand, it has received much less attention, and, to our knowledge, this is the first attempt to make use of the volcaniclastic interfacial modal mineralogy of epiclastic sandy fragments, to infer mechanical durability control at a modern beach environment. Volcaniclastic sand was collected along five beaches developed on five islands, of the southern Tyrrhenian Sea(Alicudi, Filicudi, Salina, Panarea and Stromboli) from the Aeolian Archipelago, and one sample was collected near the Stromboli Island volcanic crater. Each sample was sieved and thin sectioned for petrographic analysis. The modal mineralogy of the very coarse, coarse and medium sand fractions was determined by point-counting of the interfacial boundaries discriminating 36 types of interfaces categories, both no-isomineralic and/or no iso-structural(e.g., phenocrystal/glassy groundmass or phenocrystal/microlitic groundmass boundaries) and iso-mineralic interfaces, inside volcanic lithic grains with lathwork and porphyric textures. A total of 47,386 interfacial boundaries have been counted and, the most representative series of interfaces, from the highest to the lowest preservation, can be grouped as: a) ultrastable interfaces, categorized as Pl(Plagioclase)/Glgr(Glassy groundmass) > > Px(Pyroxene)/Glgr > > Ol(Olivine)/Glgr > > Op(Opaque)/Glgr > > Hbl(Hornblende)/Glgr> > Bt(Biotite)/Glgr > > Idd(Iddingsite)/Glgr > > Rt(Rutile)/Glgr;b) stable interfaces, categorized as Pl/Migr(Microlitic groundmass) > > Op/Migr > > Px/Migr > > Ol/Migr;c) moderately stable interfaces, categorized as Op/Px > > Op/Hbl > > Px/P > > Ol/Pl> > Bt/Op;and d) unstable interfaces, categorized as Pl/Pl > > Px/Px > > Ol/Ol > >Op/Op > > Hbl/Hbl > > Bt/Bt. Grains, eroded from the volcanic bedrock, if aff

关键词： Volcaniclastic sand Mineral interfaces Volcanic beach environment Mechanical durability

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Paleontology and evolution-part I

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Integrative Zoology 2014年第2期9卷 107-110页

作者： Maria Rita Palombo dipartimento di scienze della Terra Sapienza Universitàdi Roma Rome Italy

Evolution is one of the central unifying concepts of natural history and modern *** it is well documented by many lines of evidence from a number of scientific disciplines(***,molecular biolo-gy,comparative anatomy,biogeography),its major sup-port indeed comes from the fossil record,where the his-tory of life can be seen unravelling through geological deep *** have modified their characteris-tics over time,and new taxa have incessantly *** mechanisms and causal factors have been shap-ing this multifaceted evolutionary history?

关键词： anatomy evolution record

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On Some Numerical Semigroup Transforms

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Algebra Colloquium 2022年第3期29卷 509-526页

作者： Carmelo Cisto Universita di Messina Dipartimento di Scienze Matematiche e Informatiche Scienze Fisiche e Scienze della TerraViale Ferdinando Stagno D'Alcontres 3198166 MessinaItaly

In this paper we introduce a particular semigroup transform A that fixes the invariants involved in Wilf's conjecture,except the embedding *** also allows one to arrange the set of non-ordinary and non-irreducible numerical semigroups in a family of rooted *** addition,we study another transform,having similar features,that has been introduced by Bras-Amorós,and we make a comparison of *** particular,we study the behavior of the embedding dimension under the action of such transforms,providing some consequences concerning Wilf's conjecture.

关键词： numerical semigroup embedding dimension genus left element Wilf's conjecture

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Petrography of Middle Jurassic to Early Cretaceous sandstones in the Kutch Basin,western India:Implications on provenance and basin evolution

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Journal of Palaeogeography 2018年第3期7卷 239-252页

作者： Angana Chaudhuri Santanu Banerjee Emilia Le Pera Department of Earth Sciences Indian Institute of Technology Bombay dipartimento di Biologia Ecologia e Scienze della Terra University della

This paper investigates the provenance of Middle Jurassic to Early Cretaceous sediments in the Kutch Basin, western India, on the basis of mineralogical investigations of sandstones composition （Quartz-Feldspar-Lithic （QFL） fragment）, Zircon-Tourmaline-Rutile （ZTR） index, and mineral chemistry of heavy detrital minerals of the framework. The study also examines the compositional variation of the sandstone in relation to the evolution of the Kutch Basin, which originated as a rift basin during the Late Triassic and evolved into a passive margin basin by the end Cretaceous. This study analyzes sandstone samples of Jhumara, Jhuran and Bhuj Formations of Middle Jurassic, Upper Jurassic and Lower Cretaceous, respectively, in the Kutch Mainland. Sandstones record a compositional evolution from arkosic to subarkosic as the feldspar content decreases from 68% in the Jhumara Formation to 27% in the Bhuj Formation with intermediate values in the Jhuran Formation. The QFL modal composition indicates basement uplifted and transitional continental settings at source. Heavy mineral content of these sandstones reveals the occurrence of zircon, tourmaline, rutile, garnet, apatite, monazite and opaque minerals. Sub-rounded to well-rounded zircon grains indicate a polycyclic origin. ZTR indices for samples in Jhumara, Jhuran and Bhuj Formations are 25%, 30% and 50% respectively. Chemistry of opaque minerals reveals the occurrence of detrital varieties such as ilmenite, rutile, hematite/magnetite and pyrite, in a decreasing order of abundances. Chemistry of ilmenites in the Jhumara Formation reveals its derivation from dual felsic igneous and metabasic source, while those in Jhuran and Bhuj Formations indicate a metabasic derivation. Chemistry of garnet reveals predominantly Fe-rich （almandine） variety of metabasic origin. X-ray microscopic study provides the percentage of heavy minerals ranging from 3% to 5.260. QFL detrital modes reflect the evolution of the basin from an active rif

关键词： Siliciclastic provenance Tectonic setting Heavy minerals Mineral chemistry X-ray microscopy Mesozoic,Kutch Basin

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Sediment provenance of a carbonate bioclastic pocket beach—Le Dune(Ionian Sea,South Italy)

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Journal of Palaeogeography 2022年第2期11卷 238-255页

作者： Isabella Lapietra Stefania Nunzia Lisco Salvatore Milli Beatrice Rossini Massimo Moretti dipartimento di scienze della Terra e Geoambientali Universit a Degli Studi di BariVia Orabona 470124 BariItaly dipartimento di scienze della Terra SapienzaUniversit a di RomaPiazzale Aldo Moro 500185 RomaItaly

This study focuses on the analysis of a carbonate bioclastic pocket beach located along a coastal sector of the Apulia Ionian Sea,Le Dune beach,South *** beach develops for about 800 m and it is exposed to the south-westerly and southerly *** sediments range from very coarse to medium-fine sands and they are mainly composed of bioclasts(more than 90%)which include molluscs,foraminifers,echinoderms,algae branched,bryozoans,spicules of sponges and *** study area is one part of a marine protected reserve characterised by 15 different habitats of the typical Mediterranean submerged populations and the presence of Posidonia oceanica *** aim of our research is to highlight the correlation between physical and biological processes influencing Le Dune beach dynamics and its sediment provenance by analysing the textural and compositional characteristics of beach sands,which is fundamental for pocket beach *** beach sand analysis,deriving from textural,compositional and bioclast investigations,underlines that one of the main indicators of the beach dynamics is the bioclast component,which provides relevant information about sand provenance and sediment *** beach constitutes a semi-close system only nourished by the shells of organisms and by the erosion of headlands and dunes without important sediment interchange with adjacent littoral sectors.

关键词： Pocket beach Carbonate sediment supply Bioclast distribution Coastal dynamics

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A new chelonibiid from the Miocene of Zanzibar (Eastern Africa) sheds light on the evolution of shell architecture in turtle and whale barnacles (Cirripedia: Coronuloidea)

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Integrative Zoology 2022年第1期17卷 24-43页

作者： Alberto COLLARETA William A.NEWMAN Giulia BOSIO Giovanni COLETTI dipartimento di scienze della Terra Universitàdi PisaPisaItaly Museo di Storia Naturale Universitàdi PisaCalciItaly MBRD Scripps Institution of OceanographyLa JollaCaliforniaUSA dipartimento di scienze dell’Ambiente e della Terra Universitàdegli Studi di Milano-BicoccaMilanoItaly

The fossil history of turtle and whale barnacles(Coronuloidea:Chelonibiidae,Platylepadidae,Coronulidae and†Emersoniidae)is fragmentary and has only been investigated in *** inferences and molecular phylogenetic analyses on extant specimens suggest that the roots of whale barnacles(Coronulidae)are to be found among the chelonibiid turtle barnacles,but the hard-part modifications that enabled early coronuloids to attach to the cetacean skin are still largely to be ***,we reappraise a fossil chelonibiid specimen from the Miocene of insular Tanzania that was previously referred to the living species Chelonibia *** largely forgotten specimen is here described as the holotype of the new species†Chelonibia *** similar to ***,†*** exhibits obvious external longitudinal parietal canals occurring in-between external longitudinal parietal septa that abut outwards to form T-shaped flanges,a character so far regarded as proper of the seemingly more derived Coronulidae and *** with these features,the presence of a substrate imprint on the shell exterior indicates that†*** grasped its host’s integument in much the same way as coronulids and platylepadids,albeit without the development of macroscopic parietal buttresses and *** section analyses of the inner parietal architecture of some extant and extinct coronuloids conclusively demonstrate that vestiges of comparable external parietal microstructures are present in some living members of *** observation strengthens the unity of Coronuloidea while significantly contributing to our understanding of the evolution of the coronuloid shell structure in adapting to a diverse spectrum of hosts.

关键词： †Chelonibia zanzibarensis sp.nov. epibiosis evolution functional morphology systematics

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Asymmetric Atlantic continental margins

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Geoscience Frontiers 2021年第5期12卷 298-308页

作者： Adriano Vangone Carlo Doglioni dipartimento di scienze della Terra Sapienza UniversityRomeItaly Istituto Nazionale di Geofisica e Vulcanologia RomeItaly

We analyze the gross crustal structure of the Atlantic Ocean passive continental margins from north to the south,comparing eleven sections of the conjugate *** a general result,the western margins show a sharper continental-ocean transition with respect to the eastern margins that rather show a wider stretched and thinner *** Moho is in average about 5.7±1dipping toward the interior of the continent on the western side,whereas it is about 2.7±1in the eastern ***,the stretched continental crust is on average 244 km wide on the western side,whereas it is up to about 439 km on the eastern side of the *** systematic asymmetry reflects the early stages of the diachronous Mesozoic to Cenozoic continental rifting,which is inferred as the result of a polarized westward motion of both western and eastern plates,being Greenland,Northern and Southern Americas plates moving westward faster with respect to Scandinavia,Europe and Africa,relative to the underlying mantle.

关键词： Passive continental margin Asymmetric rift Moho dip Continental-ocean transition Westward drift of the lithosphere

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Sr,Nd,Pb and trace element systematics of the New Caledonia harzburgites:Tracking source depletion and contamination processes in a SSZ setting

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Geoscience Frontiers 2020年第1期11卷 37-55页

作者： Arianna Secchiari Alessandra Montanini Delphine Bosch Patrizia Macera Dominique Cluzel dipartimento di scienze Chimiche della Vita e della SostenibilitàAmbientaleUniversitàdi ParmaItaly Geosciences Montpellier Universitéde MontpellierFrance dipartimento di scienze della Terra Universitàdi PisaItaly Institut des Sciences Exactes et Appliquées Universitéde la Nouvelle-CalédonieNew Caledonia

The New Caledonia ophiolite(Peridotite Nappe)consists primarily of harzburgites,locally overlain by mafic-ultramafic cumulates,and minor spinel and plagioclase *** this study,a comprehensive geochemical data set(major and trace element,Sr-Nd-Pb isotopes)has been obtained on a new set of fresh harzburgites in order to track the processes recorded by this mantle section and its *** studied harzburgites are low-strain tectonites showing porphyroclastic textures,locally grading into protomylonitic *** exhibit a refractory nature,as attested by the notable absence of primary clinopyroxene,very high Fo content of olivine(91-93 mol.%),high Mg#of orthopyroxene(0.91-0.93)and high Cr#of spinel(0.44-0.71).The harzburgites are characterised by remarkably low REE concentrations(display"U-shaped"profiles,with steeply sloping HREE(DyN/YbN=0.07-0.16)and fractionated LREE-MREE segments(LaN/SmN=2.1-8.3),in the range of modern fore-arc *** modelling shows that the HREE composition of the harzburgites can be reproduced by multi-stage melting including a first phase of melt depletion in dry conditions(15%fractional melting),followed by hydrous melting in a subduction zone setting(up to 15%-18%).However,melting models fail to explain the enrichments observed for some FME(***,Sr,Pb),LREE-MREE and *** enrichments,coupled with the frequent occurrence of thin,undeformed films of Al2 O3,and CaO-poor orthopyroxene(Al2O3=0.88-1.53 wt.%,CaO=0.31-0.56 wt.%)and clinopyroxene with low Na2 O(0.03-0.16 wt.%),Al2 O3(0.66-1.35 wt.%)and TiO2(0.04-0.10 wt.%)contents,point to FME addition during fluid-assisted melting followed by late stage metasomatism most likely operated by subductionrelated melts with a depleted trace element *** isotopic ratios range from unradiogenic to radiogenic(-0.80di≤+13.32)and negatively correlate with Sr isotopes(0.70257≤87Sr/86Sr≤0.70770).Pb isotopes cover a wide range,trendi

关键词： Intra-oceanic arcs Depleted mantle sections Fore-ac harzburgites New Caledonia ophiolite Sr-Nd-Pb isotopes Subduction zones

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A classification of induced seismicity

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Geoscience Frontiers 2018年第6期9卷 1903-1909页

作者： C.Doglioni dipartimento scienze della Terra UniversitàSapienza di RomaItaly Istituto Nazionale di Geofisica e Vulcanologia RomaItaly

In order to adopt the best safety procedures, man-made earthquakes should be differentiated as a function of their origin. At least four different types of settings can be recognized in which anthropogenic activities may generate seismicity:(I) fluid removal from a stratigraphic reservoir in the underground can trigger the compaction of the voids and the collapse of the overlying volume, i.e., graviquakes; the deeper the reservoir, the bigger the volume and the earthquake magnitude;(II) wastewater or gas reinjection provides the reduction of friction in volumes and along fault planes, allowing creep or sudden activation of tectonic discontinuities, i.e., reinjection quakes;(III) fluid injection at supra-lithostatic pressure generates hydrofracturing and micro-seismicity, i.e., hydrofracturing quakes;(IV) fluid extraction or fluid injection,filling or unfilling of artificial lakes modifies the lithostatic load, which is the maximum principal stress in extensional tectonic settings, the minimum principal stress in contractional tectonic settings, and the intermediate principal stress in strike-slip settings, i.e., load quakes; over given pressure values, the increase of the lithostatic load may favour the activation of normal faults, whereas its decrease may favour thrust faults. For example, the filling of an artificial lake may generate normal fault-related ***, each setting has its peculiarities and the knowledge of the different mechanisms may contribute to the adoption of the appropriate precautions in the various industrial activities.

关键词： Anthropogenic seismicity Graviquakes Reinjection quakes Hydrofracturing quakes Load quakes

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Fault on-off versus strain rate and earthquakes energy

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Geoscience Frontiers 2015年第2期6卷 265-276页

作者： C.Doglioni S.Barba E.Carminati F.Riguzzi dipartimento di scienze della Terra Università Sapienza Istituto di Geologia Ambientale e Geoingegneria CNR Istituto Nazionale di Geofisica e Vulcanologia

We propose that the brittle-ductile transition （BDT） controls the seismic cycle. In particular, the movements detected by space geodesy record the steady state deformation in the ductile lower crust, whereas the stick-slip behavior of the brittle upper crust is constrained by its larger friction. GPS data allow analyzing the strain rate along active plate boundaries. In all tectonic settings, we propose that earthquakes primarily occur along active fault segments characterized by relative minima of strain rate, segments which are locked or slowly creeping. We discuss regional examples where large earthquakes happened in areas of relative low strain rate. Regardless the tectonic style, the interseismic stress and strain pattern inverts during the coseismic stage. Where a dilated band formed during the interseismic stage, this will be shortened at the coseismic stage, and vice-versa what was previously shortened, it will be dilated. The interseismic energy accumulation and the coseismic expenditure rather depend on the tectonic setting （extensional, contractional, or strike-slip）. The gravitational potential energy dominates along normal faults, whereas the elastic energy prevails for thrust earthquakes and performs work against the gravity force. The energy budget in strike-slip tectonic setting is also primarily due elastic energy. Therefore, precursors may be different as a function of the tectonic setting. In this model, with a given displacement, the magnitude of an earthquake results from the coseismic slip of the deformed volume above the BDT rather than only on the fault length, and it also depends on the fault kinematics.

关键词： Earthquake generation mode Strain rate Brittle-ductile transition Earthquake energy

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