1,077 research outputs found
Experimental study of vibro-acoustic response of stiffened cylindrical shells
Vibrational response of stiffened cylindrical shell to reverberant acoustic field
Geochemistry, Sr-Nd-Pb isotopes and geochronology of amphibole- and mica-bearing lamprophyres in northwestern Iran: Implications for mantle wedge heterogeneity in a paleo-subduction zone
Highlights:
• Northwestern Iranian lamprophyres have alkaline and calc-alkaline nature.
• Studied lamprophyres are emplaced during Late Cretaceous to Late Miocene time.
• Lamprophyres originated from different metasomatised lithospheric mantle.
Abstract:
Lamprophyres of different age showing distinctive mineralogy, geochemistry and isotopic ratios are exposed in northwestern Iran. They can be divided into Late Cretaceous sannaite, Late Oligocene-Early Miocene camptonite (amphibole-bearing) and Late Miocene minette (mica-bearing) and spessartite (amphibole-bearing) lamprophyres.
Sannaites have high-Ti amphibole along with high-Ti and Al clinopyroxene, and they are characterised by homogeneous enrichment in incompatible trace elements with troughs at Pb. Spessartites have hornblende and low-Al and Ti clinopyroxene, and they are characterised by enriched incompatible trace element pattern with depletions of Nb, Ta, Pb, and Ti with respect to large ion lithophile elements. Minettes have high-Ti and Al brown mica and low-Al and Ti clinopyroxene, and similarly to spessartite, are characterised by fractionation of high field strength elements with respect to large ion lithophile elements, with troughs at Nb, Ta, and Ti and a peak at Pb. Minettes show high initial 87Sr/86Sr values up to 0.70760 and low initial 143Nd/144Nd down to 0.512463 with a negative correlation, consistent with the trace element distribution related with an enriched mantle source modified after sediment recycling during subduction and continental collision.
Cretaceous sannaites and Early Miocene spessartites show low initial 87Sr/86Sr approaching 0.70447 and high 143Nd/144Nd values up to 0.512667, which are consistent with a depleted within-plate mantle source. Minette and spessartite lamprophyres show high initial 206Pb/204Pb, 207Pb/204Pb, and 208Pb/204Pb values, whereas sannaites have lower, but variable, initial 206Pb/204Pb, 207Pb/204Pb, and 208Pb/204Pb values with respect to those of calc-alkaline lamprophyres. Minettes originated by partial melting of a metasomatised lithospheric mantle following siliciclastic sediment recycling by subduction. In contrast, sannaites were generated from the partial melting of a similar lithospheric mantle that was metasomatised by within-plate agents
Subduction-legacy and Olivine Monitoring for Mantle-heterogeneities of the Sources of Ultrapotassic Magmas: The Italian case study
Eco-Industrial Parks and Sustainable Spatial Planning: A Possible Contradiction?
The definition and the subsequent development of eco-industrial parks (EIPs) have been deeply based on the application of industrial ecology theory, which pays specific attention to metabolic exchanges within industrial processes to address a deep reduction of limited resource consumption and a minimization of waste production in the framework of a sustainable development approach. Despite the EIPs configurations being essentially based on the overall idea of sustainability, the problem of defining their proper location inside the territory and the consequent land use model, to minimize land consumption, have not always been central in the wide range of studies and practices concerning the EIPs. Nevertheless, the specific problem of a drastic reduction of land consumption at the EIP planning stage acquires a crucial role and, therefore, needs to be carefully assessed inside the perspective of sustainable urban development. In this framework, the paper firstly aims at facing the nontrivial relationship between the EIPs' theorizations and implementations and the reduction of land consumption by referencing specific studies and shared tools, where new developments have been favored despite the conversion and redevelopment of existing industrial park
U and Th content in the Central Apennines continental crust: a contribution to the determination of the geo-neutrinos flux at LNGS
The regional contribution to the geo-neutrino signal at Gran Sasso National
Laboratory (LNGS) was determined based on a detailed geological, geochemical
and geophysical study of the region. U and Th abundances of more than 50
samples representative of the main lithotypes belonging to the Mesozoic and
Cenozoic sedimentary cover were analyzed. Sedimentary rocks were grouped into
four main "Reservoirs" based on similar paleogeographic conditions and
mineralogy. Basement rocks do not outcrop in the area. Thus U and Th in the
Upper and Lower Crust of Valsugana and Ivrea-Verbano areas were analyzed. Based
on geological and geophysical properties, relative abundances of the various
reservoirs were calculated and used to obtain the weighted U and Th abundances
for each of the three geological layers (Sedimentary Cover, Upper and Lower
Crust). Using the available seismic profile as well as the stratigraphic
records from a number of exploration wells, a 3D modelling was developed over
an area of 2^{\circ}x2^{\circ} down to the Moho depth, for a total volume of
about 1.2x10^6 km^3. This model allowed us to determine the volume of the
various geological layers and eventually integrate the Th and U contents of the
whole crust beneath LNGS. On this base the local contribution to the
geo-neutrino flux (S) was calculated and added to the contribution given by the
rest of the world, yielding a Refined Reference Model prediction for the
geo-neutrino signal in the Borexino detector at LNGS: S(U) = (28.7 \pm 3.9) TNU
and S(Th) = (7.5 \pm 1.0) TNU. An excess over the total flux of about 4 TNU was
previously obtained by Mantovani et al. (2004) who calculated, based on general
worldwide assumptions, a signal of 40.5 TNU. The considerable thickness of the
sedimentary rocks, almost predominantly represented by U- and Th- poor
carbonatic rocks in the area near LNGS, is responsible for this difference.Comment: 45 pages, 5 figures, 12 tables; accepted for publication in GC
Planning for More Resilient and Safer Cities: A New Methodology for Seismic Risk Assessment at the Urban Scale, Applied to a Case Study in Italy
Recent seismic events and the damages related to them have highlighted the crucial role of urban planning in coping with the fragility and intrinsic vulnerability of cities. The paper presents a methodology for assessing seismic risk at an urban scale, expanding from a single building investigation to an urban-scale analysis by adopting an empirical method for assessing the vulnerability of the urban fabric. Data collection and analysis have been conducted through the Geographic Information System (GIS). The methodology has been applied to the Italian city of Castelfranco Emilia, in the Emilia-Romagna region, where the current regional urban planning law is guiding municipalities towards the development of strategies mostly oriented toward the retrofit of the existing building stock and the overall regeneration of the urbanized territory, in accordance with the target of no net land take by 2050. The novelty of the method stands in the transposition of approaches born in the civil engineering and protection domains to the urban planning sphere, stressing the importance of developing urban planning instruments which are well-integrated with vulnerability assessments and, therefore, able to successfully incorporate risk considerations in the decision making
- …
