1,721,168 research outputs found
Shanghai, between China and the World. Exception and rule of an exemplary city / Shanghai, tra Cina e Mondo. Eccezione e regola di una città esemplare
No full textPrograms and goals
No full textNew Next Nature takes root in precise places and flourishes by exploiting the conditions of the “suspended”
and “waiting” areas. OC OPEN CITY International Summer School has always had, since its first edition in
2010, a recognizable identity: to develop projects with
global themes, experimenting and testing them locally,
in the complementary landscapes that the particular
urban and territorial condition of Piacenza gives us.
The preparatory phase for OC2017 has further strengthened this double register by developing a rich and integrated background where the dense and stable parts of
city is continuously compared with large areas (highlighted in yellow and black in the diagram alongside)
available for transformation. The will of the OC direction and coordination is precise to the condition that no
categories are proposed: empty areas and abandoned
areas, internal areas and external areas, private areas
and public areas, areas with precise functional destination and areas without definition
Kilometre-scale strain partitioning of the Mont Morion Permian metaintrusives during Alpine subduction (Dent-Blanche Unit, Valpelline - Western Italian Alps)
No full textLa presente carta mostra l’evoluzione strutturale e metamorfica dei litotipi dal Permiano ad oggi. Le rocce pre-Permiane preservate come incassanti all’interno degli intrusivi Permiani. Durante la riequilibrazione Alpina tali rocce sono state trasformate in metaintrusivi da coronitici a milonitici associati a gneiss a mica bianca e glaucofane. Sulla carta sono riportate le tracce delle foliazioni e dei piani assiali, distinte sulla base della loro cronologia relativa e mineralogia caratteristica. Tali informazioni raccolte in una singola carta permettono di ricostruire i diversi stadi evolutivi di tale porzione crostale, dall’estensione pre-Alpina, seguita dalla fase intrusiva Permiana, fino alla subduzione e relativa collisione Alpina.The structural and metamorphic evolution of Mont Morion Complex lithotypes, from pre-Permian to present, is presented. We identified pre-Permian rocks (e.g. amphibolite, biotite-bearing gneiss and acid granulite) preserved as roof pendants (i.e. xenoliths) within Permian intrusives. Permian intrusives and xenoliths are re-equilibrated during the Alpine time and coronitic to mylonitic metaintrusives are produced, due to meter to kilometer-scale fabric gradients, with associated white mica-, glaucophane-bearing gneiss. The tectono-metamorphic map shows the traces of the superimposed foliations and the fold axial planes. The foliations are distinguished on the basis of their relative chronology and mineralogical support. Using these structural data, reported on a single map, the successive stages of this portion of the Adria plate can be reconstruct: (i) a pre-Alpine extension, recorded by granulite- to amphibolite-facies xenolits; (ii) the Permian magmatic phase (e.g. Mont Morion, Mont Collon and Matterhorn intrusives); (iii) the Alpine subduction and subsequent collision
The thermal state of Biella pluton country rocks as a tool to unravel the late orogenic tectonics of the Western Alps
Full text linkCrustal level and timing of late-orogenic plutons represent powerful tools for constraining the late exhumation history of tectonic units, within collisional belts. This work aims to contribute to this topic by quantitatively determining the thermal state of Biella Periadriatic pluton country rocks during its emplacement within the continental HP metamorphic rocks of the Sesia-Lanzo Zone (SLZ), in the western Austroalpine domain (Zanoni et al., 2008, 2010; Zanoni, 2016 and refs. therein). During the Alpine subduction and exhumation, the Sesia-Lanzo Zone records a polyphasic tectono-metamorphic evolution. Pluton cooling involved contact metamorphism overprinting eclogitic to greenschist facies assemblages in the country rocks. On the basis of the amount and type of contact metamorphic assemblages the aureole extent was mapped and the variation of recorded thermal peak validated by comparison with numerical modelling of the heat transfer during magma crystallisation. Thus, this work aims constraining the late exhumation history of the internal western Alps by determining the crustal level of pluton emplacement and the thermal gradient of its country rocks at the time of intrusion.
The Alps developed during subduction and closure of the Mesozoic Tethys and subsequent continental collision over Cretaceous–Oligocene times (e.g. Dal Piaz, 2010; Handy et al., 2010; Spalla et al., 2010). The Alpine convergent system involved the subduction of the European lithosphere underneath the Adria plate. The Periadriatic line is a main crustal break of the Alpine bounding the Southalpine continental crust acting as backstop wall of the orogenic wedge during the convergence (Polino et al., 1990). This lineament (Fig. 1) separates tectonic units that during the Alpine convergence experimented intense deformation and metamorphism (i.e. Austroalpine and Penninic domains) from rocks that recorded only shallow structural level deformation (i.e. Southalpine domain). The Periadriatic line is interpreted as the ascent path for the late collisional Oligocene magmas, which emplaced to form the Periadriatic plutons (Rosenberg, 2004). The Periadriatic plutons are traditionally considered as derived from the Alpine slab breakoff (Von Blanckenburg and Davies, 1995). However recently the Tertiary magmatic rocks south of the Periadriatic line, such as the southern Adamello pluton, Veneto Volcanic province, and dykes in the central Southalpine, are supposed to be generated during Alpine subduction (Tiepolo et al., 2011; Bartoli et al., 2013; Bergomi et al., 2015). The Austroalpine domain of the western Alps consists of continental rocks tectonically sampled by the margin of Adria plate during subduction (e.g. Roda et al., 2012) and is actually divided into two main tectonic units, namely the Sesia-Lanzo Zone (SLZ) and Dent Blanche nappe. Both tectonic units were subducted and exhumed during the Alpine cycle when the oceanic subduction was still active (Spalla et al., 1996; Babist et al., 2006; Roda et al., 2012). Between 60 and 80 Ma the SLZ reached the P-peak during subduction (Bussy et al., 1998; Cenki-Tok et al., 2011), corresponding to eclogite conditions at about 550°C and ≥ 2 GPa (Zucali et al., 2002; Zucali and Spalla, 2011). Eclogite metamorphism is followed by decompression blueschist and greenschist re-equilibrations (Pognante et al., 1980; Zucali et al., 2002), related to later exhumation stages (e.g. Spalla et al., 1991). The shallower levels of the exhumation path took place between 45 and 30 Ma (Inger et al., 1996; Cortiana et al., 1998; Babist et al., 2006; Zanoni et al., 2010). To the east the SLZ is delimited by the Periadriatic line and in its inner part hosts the Biella and Traversella plutons (Zanoni et al., 2008; Zanoni 2010, 2016). The Biella pluton shows concentric zoning with the outer part constituted by monzonite and the inner part by syenite and granite and a calc- alkaline composition (Bigioggero et al., 1994). The pluton has been dated at about 30 Ma (Romer et al., 1996; Berger et al., 2012) and its country rocks belong to the Eclogitic Micaschists Complex (Fig. 2). Along the northeaster and southwester margins of the
Biella pluton country rocks consist of metapelites, meta-aplites and metagranitods with minor metabasites. During the Alpine convergence country rocks recorded up to six ductile deformation stages that predated the intrusion of the pluton. Only locally syn-intrusive folding and faulting are recorded in the country rocks. Generally brittle structures post-date pluton emplacement. The igneous rocks record a magmatic foliation that in place is parallel to the pluton margin. During the emplacement the country rocks recorded different type of contact metamorphism assemblages that vary with the country rock type and the distance from the pluton margin. The contact metamorphism parageneses form ne-grained coronitic structures that overprinted eclogite parageneses and local greenschist parageneses. With the distance from the pluton the amount of contact metamorphism parageneses decrease. Close to the pluton margin the contact metamorphic mineral assemblages are characterised by plagioclase, K-feldspar, cordierite, biotite, spinel, Al-silicate (sillimanite closer and andalusite farer from the pluton), and locally corundum, orthopyroxene and garnet. Locally, up to about 10 m far from the pluton margin, partial melting is recorded. With the distance from the pluton corundum, orthopyroxene, garnet, spinel, and sillimanite disappear. The contact metamorphic minerals are detected up to about 900 m far from the pluton in plain view (Fig. 2). In igneous rocks interstitial amphibole has an Al content compatible with intrusion depth variable between 4 and 7 km. Ti content in amphibole and equilibrium between amphibole and plagioclase are consistent with intrusion temperature between 670 and 720°C (Zanoni et al., 2010). In the country rocks temperature peak, reached during pluton crystallisation, vary between about 700°C at the pluton margin, and 550°C at about 600 m far from the pluton (Zanoni et al., 2010). The comparison of thermal estimates in the country rocks with a 2D conductive thermal model for pluton cooling shows that the best t is for initial temperature in the country rocks between 430 and 530°C at 8 km depth (Fig. 3). That involves a thermal gradient of the country rock at time of intrusion ranging between 55 and 65°C/km. The crustal level of Biella pluton emplacement is as shallow as a few kilometres and this is consistent with magmatic rocks intersecting all ductile structures in the country rocks and with contact metamorphism assemblages replacing greenschist facies assemblages. The computed extent of the aureole for the simulations is wider than the mapped one because the computed thermal boundary of the aureole is between 300 and 400°C. Finally, the thermal gradient of the country rocks at the time of pluton intrusion is suf ciently high to justify the emplacement of Biella pluton during the accomplishment of the break-off of the Alpine slab
Tectono-metamorphic map of the Mont Morion Permian metaintrusives (Mont Morion - Mont Collon - Matterhorn Complex, Dent Blanche Unit), Valpelline - Western Italian Alps
Full text linkThe presented map displays the structural and metamorphic evolution of lithotypes from pre-Permian to present. We distinguish pre-Permian rocks (e.g., amphibolite, biotite-bearing gneiss and acid granulite) preserved as roof pendants (i.e., xenoliths) within Permian intrusives. Permian intrusives and hosted xenoliths are then re-equilibrated during Alpine evolution, producing coronitic to mylonitic metaintrus-ives, due to meter to kilometer-scale fabric gradients, and associated white mica-, glaucophane-bearing gneiss. The map also shows the traces of the superimposed foliations and the fold axial planes. The traces are distinguished on the basis of their relative chronology and mineralogical support. This information, reported on a single map, allows us to reconstruct the successive stages of this fragment belonging to the African plate continental crust, from the pre-Alpine extension, recorded by granulite- to amphibolite-facies xenolits, to the Permian intrusive phase (e.g., Mont Morion, Mont Collon and Matter-horn intrusives) lasting with the Alpine subduction-collision related evolution. The Mont Morion, part of the Mont Morion-Mont Collon-Matterhorn Complex of the Dent Blanche unit, may be interpreted as a multi-stadial Alpine km-scale shear zone, where Permian intrusive rocks are transformed into white mica chlorite-bearing or glaucophane-bearing gneisses along high-strain horizons (100 m-thick), while within low-strain cores (100- to 1000 m-thick), meta-intrusives preserve igneous features and xenoliths of am-phibolites, acid granulites and biotite-bearing gneisses. In this paper, an outcrop tectono-metamorphic map (1:10,000 scale) is presented, based upon fieldwork at 1:5,000 together with an interpretative map (1:15,000 scale), in which three dimensional relationships are described, and micro- to mesoscopic fabric types are shown, corresponding to finite strain states recorded by rocks
Meso and microstructural evolution of the Mont Morion metaintrusive complex (Dent-Blanche nappe, Austroalpine domain, Valpelline, Western Italian Alps)
No full textThe Mont Morion complex of the Dent Blanche nappe is interpreted as a multi-stadial Alpine km-scale shear zone. Permian intrusive rocks are transformed into white mica chlorite-bearing or glaucophane-bearing gneisses along high-strain horizons (100m-thick), while within low-strain cores (100- to 1000m-thick), metaintrusives preserve igneous features and xenoliths of amphibolites, acid granulites and biotite-bearing gneisses.
Ten superposed evolutionary stages (1 to 10) occurred: from pre-Permian (1 and 2, only in pre-intrusive host rocks) to Permian-Triassic (3 and 4) and Mesozoic-Cenozoic (5 to 10). Stages 1 and 2 developed under amphibolite to granulite-facies conditions. During stage 3, the Mont Morion complex was intruded (P-range = 0.25-0.70 GPa at T between 600-760°C). Stage 4 occurred under greenschist facies conditions. Stages 5 and 6 are associated with the development of tectonitic mylonitic km-scale domains under blueschist facies conditions. Stage 7 is represented by folding of S6 under greenschist-facies conditions. Metre-scale shear zones developed during stages 8, 9 and 10. The pre-Alpine part of the P-T-t-d path is interpreted as trace of post-collisional thinning Variscan continental crust, related to the upwelling of magmas (e.g. Mont Collon-Matterhorn gabbros; Arolla granites); the Alpine part of the P-T-t-d path is interpreted as record of continental crust subduction and exhumation, related to the Alpine oceanic-continental subduction and continental collision
Testing the thermal state of Biella pluton country rocks via numerical model of magma cooling
Full text linkThe Biella pluton (30-31 Ma) is a Periadriatic intrusive of the Alps, emplaced in the internal part of the HP continental Sesia Lanzo Zone (Berger et al., 2012). Pluton cooling involved contact metamorphism overprinting eclogitic to greenschist facies assemblages in country rocks. Multiscale structural analysis combined with thermos-barometric estimates suggest that magma intrusion took place at shallow crustal levels (Zanoni et al., 2008; Zanoni et al., 2010; Zanoni, 2015).
The emplacement history indicates that the intrusion of Biella body occurred when the Sesia Lanzo Zone had almost completed its exhumation under low thermal state consistent with an ongoing subduction (e.g. Roda et al., 2012 and refs therein). The mechanism proposed for triggering the Periadriatic magmatism are either subduction (Tiepolo et al., 2014) or slab break-off (e.g. Von Blankenburg & Davies, 1995). However recent numerical modeling (Freeburn et al., 2015) suggests that a slab break-off related melting does not result in the widespread magmatism characterizing many collisional belts.
In order to unravel the thermal state of the Biella stock country rocks at the intrusion time we develop a preliminary 2D thermal model of pluton cooling testing four different thermal gradients of the host rocks. We compare the extent and the variation in the thermal peak of the contact aureole recorded in the country rock (Fig. 1) with the results of the numerical simulations.
The computed thermal boundary of the aureole is between 300 and 400°C and is wider than the mapped one due to the difficulty to distinguish between contact and greenschists regional metamorphism at such low temperatures. The best fit occurs for the simulation accounting for temperatures between 427 and 527°C (700 and 800 K) at 8 km depth (Fig. 2), assuming conduction as the only effective heat transfer mechanism. This indicates that the emplacement occurred under thermal gradients between 55 and 65°C/km that would exclude a syn-subductive magmatism. The suggested thermal gradient for the country rock of the Biella pluton would represent the constraint for testing different scenarios responsible for the generation of Periadriatic magmatism
Landscape Of[f] Limits
Full text linkThe essay explores the evolving and increasingly complex field of landscape architecture, emphasizing its plural and interdisciplinary nature. The author highlights how contemporary landscape practice must account for layered and dynamic relationships between visible and invisible forces, human and non-human agents, and macro- and micro-scale processes. Time, particularly in the context of the Anthropocene, is positioned as a crucial dimension that reshapes how we perceive and engage with landscapes.
Protasoni calls for a shift in perspective, where the landscape architect is not external to the context but embedded within it—as a professional, intellectual, and living being. This involvement demands not only technical skill but also ethical and interpretive engagement, acknowledging that transformation processes involve diverse and often conflicting interests, norms, and representations. The essay argues for a renewed ecological and ethical commitment in landscape design, one that abandons rigid binaries (e.g., nature vs. human) and embraces a networked understanding of environmental responsibility. The Landscape Of[f] Limits program, within this framework, is proposed as a platform for this new, inclusive approach to landscape transformatio
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