469 research outputs found

    EVOLUTION OF THE SUBCONTINENTAL LITHOSPHERE DURING MESOZOIC TETHYAN RIFTING: CONSTRAINTS FROM THE EXTERNAL LIGURIAN MANTLE SECTION (NORTHERN APENNINE, ITALY)

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    Our study is focussed on mantle bodies from the External Ligurian ophiolites, within the Monte Gavi and Monte Sant'Agostino areas. Here, two distinct pyroxenite-bearing mantle sections were recognized, mainly based on their plagioclase-facies evolution. The Monte Gavi mantle section is nearly undeformed and records reactive melt infiltration under plagioclase-facies conditions. This process involved both peridotites (clinopyroxene-poor lherzolites) and enclosed spinel pyroxenite layers, and occurred at 0.7–0.8 GPa. In the Monte Gavi peridotites and pyroxenites, the spinel-facies clinopyroxene was replaced by Ca-rich plagioclase and new orthopyroxene, typically associated with secondary clinopyroxene. The reactive melt migration caused increase of TiO2 contents in relict clinopyroxene and spinel, with the latter also recording a Cr2O3 increase. In the Monte Gavi peridotites and pyroxenites, geothermometers based on slowly diffusing elements (REE and Y) record high temperature conditions (1200-1250 °C) related to the melt infiltration event, followed by subsolidus cooling until ca. 900°C. The Monte Sant'Agostino mantle section is characterized by widespread ductile shearing with no evidence of melt infiltration. The deformation recorded by the Monte Sant'Agostino peridotites (clinopyroxene-rich lherzolites) occurred at 750–800 °C and 0.3–0.6 GPa, leading to protomylonitic to ultramylonitic textures with extreme grain size reduction (10–50 μm). Compared to the peridotites, the enclosed pyroxenite layers gave higher temperature-pressure estimates for the plagioclase-facies re-equilibration (870–930 °C and 0.8–0.9 GPa). We propose that the earlier plagioclase crystallization in the pyroxenites enhanced strain localization and formation of mylonite shear zones in the entire mantle section. We subdivide the subcontinental mantle section from the External Ligurian ophiolites into three distinct domains, developed in response to the rifting evolution that ultimately formed a Middle Jurassic ocean-continent transition: (1) a spinel tectonite domain, characterized by subsolidus static formation of plagioclase, i.e. the Suvero mantle section (Hidas et al., 2020), (2) a plagioclase mylonite domain experiencing melt-absent deformation and (3) a nearly undeformed domain that underwent reactive melt infiltration under plagioclase-facies conditions, exemplified by the the Monte Sant'Agostino and the Monte Gavi mantle sections, respectively. We relate mantle domains (1) and (2) to a rifting-driven uplift in the late Triassic accommodated by large-scale shear zones consisting of anhydrous plagioclase mylonites. Hidas K., Borghini G., Tommasi A., Zanetti A. & Rampone E. 2021. Interplay between melt infiltration and deformation in the deep lithospheric mantle (External Liguride ophiolite, North Italy). Lithos 380-381, 105855

    Impact of Etna’s volcanic emission on major ions and trace elements composition of the atmospheric deposition

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    Mt. Etna, on the eastern coast of Sicily (Italy), is one of the most active volcanoes on the planet and it is widely recognized as a big source of volcanic gases (e.g., CO2 and SO2), halogens, and a lot of trace elements, to the atmosphere in the Mediterranean region. Especially during eruptive periods, Etna’s emissions can be dispersed over long distances and cover wide areas. A group of trace elements has been recently brought to attention for their possible environmental and human health impacts, the Technology-critical elements. The current knowledge about their geochemical cycles is still scarce, nevertheless, recent studies (Brugnone et al., 2020) evidenced a contribution from the volcanic activity for some of them (Te, Tl, and REE). In 2021, in the framework of the research project “Pianeta Dinamico”, by INGV, a network of 10 bulk collectors was implemented to collect, monthly, atmospheric deposition samples. Four of these collectors are located on the flanks of Mt. Etna, other two are in the urban area of Catania and three are in the industrial area of Priolo, all most of the time downwind of the main craters. The last one, close to Cesarò (Nebrodi Regional Park), represents the regional background. The research aims to produce a database on major ions and trace element compositions of the bulk deposition and here we report the values of the main physical-chemical parameters and the deposition fluxes of major ions and trace elements from the first year of research. The pH ranged from 3.1 to 7.7, with a mean value of 5.6, in samples from the Etna area, while it ranged between 5.2 and 7.6, with a mean value of 6.4, in samples from the other study areas. The EC showed values ranging from 5 to 1032 μS cm-1, with a mean value of 65 μS cm-1. The most abundant ions were Cl- and SO42- for anions, Na+ and Ca+ for cations, whose mean deposition fluxes, considering all sampling sites, were 16.6, 6.8, 8.4, and 6.0 mg m-2 d, respectively. The highest deposition fluxes of volcanic refractory elements, such as Al, Fe, and Ti, were measured in the Etna’s sites, with mean values of 948, 464, and 34.3 μg m-2 d-1, respectively, higher than those detected in the other sampling sites, further away from the volcanic source (26.2, 12.4, 0.5 μg m-2 d-1, respectively). The same trend was also observed for volatile elements of prevailing volcanic origin, such as Tl (0.49 μg m-2 d-1), Te (0.07 μg m-2 d-1), As (0.95 μg m-2 d-1), Se (1.92 μg m-2 d-1), and Cd (0.39 μg m-2 d-1). Our preliminary results show that, close to a volcanic area, volcanic emissions must be considered among the major contributors of ions and trace elements to the atmosphere. Their deposition may significantly impact the pedosphere, hydrosphere, and biosphere and directly or indirectly human health

    Impact of geogenic degassing on C-isotopic composition of dissolved carbon in karst systems of Greece

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    The Earth C-cycle is complex, where endogenic and exogenic sources are interconnected, operating in a multiple spatial and temporal scale (Lee et al., 2019). Non-volcanic CO2 degassing from active tectonic structures is one of the less defined components of this cycle (Frondini et al., 2019). Carbon mass-balance (Chiodini et al., 2000) is a useful tool to quantify the geogenic carbon output from regional karst hydrosystems. This approach has been demonstrated for central Italy and may be valid also for Greece, due to the similar geodynamic settings. Deep degassing in Greece has been ascertained mainly at hydrothermal and volcanic areas, but the impact of geogenic CO2 released by active tectonic areas has not yet been quantified. The main aim of this research is to investigate the possible deep degassing through the big karst aquifers of Greece. Since 2016, 156 karst springs were sampled along most of the Greek territory. To discriminate the sources of carbon, the analysis of the isotopic composition of carbon was carried out. δ13CTDIC values vary from -16.61 to -0.91‰ and can be subdivided into two groups characterized by (a) low δ13CTDIC, and (b) intermediate to high δ13CTDIC with a threshold value of -6.55‰. The composition of the first group can be related to the mixing of organic-derived CO2 and the dissolution of marine carbonates. Springs of the second group, mostly located close to Quaternary volcanic areas, are linked to possible carbon input from deep sources

    Crit-i-kit (playing cards and raw list)

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    Crit-i-kit is a game that explores the tools, equipment and supplies that are considered ‘essential’ to the inhabitation of landscape. Walkers encountered by the artist in a variety of environments anonymously shared the complete contents of the bags they were carrying at the time; items were then catalogued and grouped into broad thematic categories. Each category is printed onto a card that is then randomly selected by a player and used to guide a new walk. This work prompts consideration of the structures we individually build and respond to as we walk within the world. Each item is proposed as a structure that guides our inhabitation; a vessel for carrying, a gesture of care, or an item of potential are each thought of as prompts for spontaneous architectures that result in profoundly different modes of liv-ing

    Digital fault mapping and spatial attribute analysis of basement-influenced oblique extension in Passive margin settings

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    Oblique extension and passive margin segmentation may be attributed to the influence of basement structures. Pre-existing fabrics exert a strong control on the overall rift geometry in extensional settings, and can lead to the development of complex fault patterns, obliquely extending segments, deformation partitioning and transfer zones. In offshore settings, the nature of basement structure cannot easily be determined from seismic data, and onshore studies are increasingly used to assess basement controls. A digital mapping methodology GAVA (Geospatial Acquisition Visualisation and Analysis) has been developed to integrate regional- to outcrop-scale data. Digital field mapping methods using DGPS, Laser-Rangefinder and field-GIS are used to map faults to a dm- to mscale accuracy by collecting spatial co-ordinates on a handheld computer whilst traversing along or across the exposed fault systems. Benefits of digital mapping include: more rapid data collection and analysis; all data geospatially located and stored in a digital database; GIS-based analysis and visualisation techniques; digital data format enables direct comparison with fault arrays interpreted from seismic data. The GAVA workflow has been used to investigate three case studies on the North Atlantic Passive Margin: 1) NW Scotland; 2) Lofoten, NW Norway; and 3) Davis Strait, West Greenland. Each case study combines regional onshore and offshore mapping, using remote sensing and seismic interpretation, with detailed outcrop mapping of onshore fault exposures. Fault attributes (e.g. fault orientation, kinematics, fault linkage, fault-rock, overprinting relationships) observed at individual localities were collected in a GIS database. Kinematic fault analysis was carried out using strain inversion techniques at various scales. Spatial analysis was carried out using ArcGIS to identify relationships between various structures, while 3-D models were constructed in order to visualise these relationships over several orders of magnitude. Results show that the complexity of rifted margins may be linked to changes in the obliquity of pre-existing structures relative to the regional extension vector. However, direct reactivation of structures need not always occur. The influence of pre-existing structures may also lead to localized variations in stress/strain orientations, which if analyzed in isolation can indicate extension non-parallel to regional stresses. Therefore, spatial analysis and studies across a range of scales is essential when analyzing such zones. Digital (GIS) mapping methods are an ideal may to carry out such studies, although further development of analysis and visualisation tools for geosciences is required in the field of GIS

    PROTOTYPING PLATEAU GEHRY_CONNECTIVES : Reading Frank Gehry’s experiments through Deleuze and Guattari

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    This thesis attempts to describe and interpret the design practice of an American architect, Frank O. Gehry through concepts developed by French philosopher Gilles Deleuze and his collaborator, French psychotherapist, philosopher and activist, Félix Guattari. At the same time, prototyping a website-based interactive project called PLATEAU GEHRY_CONNECTIVES, it explores an alternative form for the Doctoral thesis. In addition to connections with visual arts, such as painting and cinema, the experimental project PLATEAU GEHRY_CONNECTIVES includes references to concepts and phenomena from various areas of knowledge revealing distinctive, unusual qualities of Gehry’s creative approach in the production of design artefacts. The thesis documents and discusses means of representation in architectural design fused into the specific creative culture of Frank O. Gehry. It notices that the discourse in architectural theory and practice, often neglects what occurs on a particular molecular level of the architectural design process. It shows that elements of micro-level of design procedures render Gehry’s idiosyncratic design phenomena intelligible and perceptible in a new way. It claims that it has been possible because Deleuze and Guattari’s concepts become perceptibly operational in the interpretation of such phenomena, at the level of elementary units of Gehry’s design procedures. Moreover, through this close-up perspective, the thesis’ investigations identify certain similarities in the operational modes of the architect and the painter. It demonstrates how Gehry, who has anchored his interest in painting, and specifically in what he defined as ‘immediacy in painting,’ was able to transform the practice of architectural drawing from projective to a cognitive one. It also shows, how the architect re-defines the commonly applied projective geometries from passive, arbitrary role to an active agent, and how the architect links drawing practice with the construction process on a new, almost palpable level. While stressing its the manual character, the thesis demonstrates that Gehry’s explorative culture of challenging means of representation employed in architectural design production facilitates the re-disciplining of architecture culminating in the integration of the CATIA system in the design procedures. This study of Gehry’s design actions and strategies can help the reader to understand the significance of experimental and intuitive design practices. The thesis proposes the Deleuzian interpretation of Gehry’s experiments in the aesthetics of design thinking and acting. It renders perceptions of patterns, according to which, other design practices can operate

    Landscape Strategies in Architecture

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    The central question and purpose of the thesis is to understand how landscape as a design concept is changing our understanding of architecture. It explores the ways in which landscape is relevant for design strategies in architecture. Buildings that have been designed like landscapes have become a topic in contemporary architecture and in the recent literature about it. The apparent distinction between architecture and landscape is questioned in exemplary theoretical works and building designs with increasing interest in landscape as a phenomenon of contemporary architecture. To understand this phenomenon this thesis first explores the term of landscape and its design. The introduction focuses on the exploration of the idea of landscape and how it is applicable in architectural design. Strategies of landscape design as they are discussed in contemporary landscape architecture are defined and illustrated with specific examples. This view is contrasted with the idea of nature in architecture. Architecture's concepts of nature reveal some crucial problems that lead to the polarity of 'wild' nature and 'human' architecture. With a critique of these common architectural theories and within the methodological differentiation the thesis reveals the necessity of research through analysis of landscape spatial composition in architecture. The core of this thesis is three case studies of architectural designs that approach a building like a landscape. A selection of analytical techniques is applied to key cases in three central chapters. The main analytical model for landscape architectural composition that Steenbergen and Reh (2003) developed for the European Gardens of the Renaissance, Baroque and Enlightenment is applied as a drawing analysis of the formal composition of three selected contemporary architectural projects in a period from 1992 to 2015. Each of the three building designs is studied with the same four-layer method of design analysis. In conjunction with this comparative analysis, a project specific method that reveals unique aspects of each design has been developed. The first case is OMA's unbuilt Jussieu design for two university libraries in Paris. In 1992 Dutch architect Rem Koolhaas and his collaborators at OMA proposed the Jussieu project at a turning point of the discipline, where new forms of architecture with landscape design strategies were being explored. Though this project has not been realised, this thesis makes it possible to describe the building in a guided walk-through. This visualisation of the design as it could have looked if built is also the specific analytical method chosen for this example. The second case, the Rolex Learning Centre at EPF Lausanne, has been clearly declared 'landscape' as architecture by its designers. This competition winning design from 2004 and opened in 2010 is the largest scale international building of Japanese Architects Kazuyo Sejima and Ryue Nishizawa (SANAA). The specific analytical method used for this case is a visual space analysis of the project using 3D-isovists. The third case is the City of Culture of Galicia in Santiago de Compostela by American architect Peter Eisenman. This project was initially designed in 1999 in a process of layering - in principle, similar to the layer model analysis of this thesis. However, the four tenets of the thesis layer model - ground form, spatial form, metaphorical form and programmatic form - will alter the reading of this project. This execution of the giant public project of "City of Culture" was interrupted half-way in 2015, with great political difficulties fo Galicia. The specific analytical method used for this case is an experiment that uses the ruins of unbuilt architecture as the base for a landscape architectural design. This design of a temporary garden mimics the design principles of architect Peter Eisenman. This experiment shows that landscape strategies developed for the design of a building can be applied in reverse for designed landscapes. In conclusion, this thesis will compare the three case studies of architectural designs with each other. While some design instruments, strategies and methods are specific, others are commonly applied in several or all of the projects. In a broader scope, the analysis is transposed into the greater societal and theoretical realm to explore whether landscape design strategies change architecture. For the discipline of architecture in general, the thesis explores how far landscape could lead the profession further as a new concept to build a sustainable human environment. Evoking potential applications and the reach of landscape in architecture in the perspective of future development, the thesis ultimately discusses unexplored potentials for landscape design strategies in the architectural discipline

    Landscape Strategies in Architecture

    Get PDF
    The central question and purpose of the thesis is to understand how landscape as a design concept is changing our understanding of architecture. It explores the ways in which landscape is relevant for design strategies in architecture. Buildings that have been designed like landscapes have become a topic in contemporary architecture and in the recent literature about it. The apparent distinction between architecture and landscape is questioned in exemplary theoretical works and building designs with increasing interest in landscape as a phenomenon of contemporary architecture. To understand this phenomenon this thesis first explores the term of landscape and its design. The introduction focuses on the exploration of the idea of landscape and how it is applicable in architectural design. Strategies of landscape design as they are discussed in contemporary landscape architecture are defined and illustrated with specific examples. This view is contrasted with the idea of nature in architecture. Architecture's concepts of nature reveal some crucial problems that lead to the polarity of 'wild' nature and 'human' architecture. With a critique of these common architectural theories and within the methodological differentiation the thesis reveals the necessity of research through analysis of landscape spatial composition in architecture. The core of this thesis is three case studies of architectural designs that approach a building like a landscape. A selection of analytical techniques is applied to key cases in three central chapters. The main analytical model for landscape architectural composition that Steenbergen and Reh (2003) developed for the European Gardens of the Renaissance, Baroque and Enlightenment is applied as a drawing analysis of the formal composition of three selected contemporary architectural projects in a period from 1992 to 2015. Each of the three building designs is studied with the same four-layer method of design analysis. In conjunction with this comparative analysis, a project specific method that reveals unique aspects of each design has been developed. The first case is OMA's unbuilt Jussieu design for two university libraries in Paris. In 1992 Dutch architect Rem Koolhaas and his collaborators at OMA proposed the Jussieu project at a turning point of the discipline, where new forms of architecture with landscape design strategies were being explored. Though this project has not been realised, this thesis makes it possible to describe the building in a guided walk-through. This visualisation of the design as it could have looked if built is also the specific analytical method chosen for this example. The second case, the Rolex Learning Centre at EPF Lausanne, has been clearly declared 'landscape' as architecture by its designers. This competition winning design from 2004 and opened in 2010 is the largest scale international building of Japanese Architects Kazuyo Sejima and Ryue Nishizawa (SANAA). The specific analytical method used for this case is a visual space analysis of the project using 3D-isovists. The third case is the City of Culture of Galicia in Santiago de Compostela by American architect Peter Eisenman. This project was initially designed in 1999 in a process of layering - in principle, similar to the layer model analysis of this thesis. However, the four tenets of the thesis layer model - ground form, spatial form, metaphorical form and programmatic form - will alter the reading of this project. This execution of the giant public project of "City of Culture" was interrupted half-way in 2015, with great political difficulties fo Galicia. The specific analytical method used for this case is an experiment that uses the ruins of unbuilt architecture as the base for a landscape architectural design. This design of a temporary garden mimics the design principles of architect Peter Eisenman. This experiment shows that landscape strategies developed for the design of a building can be applied in reverse for designed landscapes. In conclusion, this thesis will compare the three case studies of architectural designs with each other. While some design instruments, strategies and methods are specific, others are commonly applied in several or all of the projects. In a broader scope, the analysis is transposed into the greater societal and theoretical realm to explore whether landscape design strategies change architecture. For the discipline of architecture in general, the thesis explores how far landscape could lead the profession further as a new concept to build a sustainable human environment. Evoking potential applications and the reach of landscape in architecture in the perspective of future development, the thesis ultimately discusses unexplored potentials for landscape design strategies in the architectural discipline
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