2,168 research outputs found
Photo-lithological map of the southern flank of the Tindouf Basin (Western Sahara)
No full textThis paper examines the potential to map surface geology by applying specific enhancement techniques to Landsat 7 ETM+ imagery, resulting in false color composite images, which were interpreted and then validated during a field campaign. The study area is located on the southern flank of the Tindouf Basin (Western Sahara), and it is noted that there is a general lack of bibliographic data due both to the region's remote location and to its difficult political situation. A number of photo-lithological units were mapped within the Proterozoic basement and the sedimentary succession of the Tindouf Basin incisively contributing to the knowledge of the geological setting of this area. © 2012 Andrea Ciampalini, Francesca Garfagnoli, Benedetta Antonielli, Chiara Del Ventisette and Sandro Moretti
Quantitative mapping of clay minerals using airborne imaging spectroscopy: New data on mugello (Italy) from SIM-GA prototypal sensor
No full textThe possibility of using high spectral and spatial resolution remote sensing technologies is becoming increasingly important in the monitoring of soil degradation processes. A high spatial resolution hyperspectral dataset was acquired with the airborne Hyper SIM-GA sensor from Selex Galileo, simultaneously with ground soil spectral signatures and samples collection. A complete mapping procedure was developed using the 2000-2450 nm spectral region, demonstrating that the 2200 absorption band allows the obtainment of reliable maps of the clay content. The correlation achieved between the observed and the predicted values is encouraging for the extensive application of this technique in soil conservation planning and protection actions
Remote sensing techniques using Landsat ETM+ applied to the detection of iron ore deposits in Western Africa
No full textRemote sensing methods enable the rapid and inexpensive mapping of surface geological and mineralogical features. This capability proves highly useful when working on isolated or inaccessible areas. In this study, several enhancements of Landsat Enhanced Thematic Mapper plus (i.e. band ratios, false colour composites and principal component analysis) were used and evaluated to obtain the best possible visualisation of iron deposits hosted in the Devonian sedimentary rocks of northwestern Africa. In particular, two test sites were chosen: southern Algeria (Djebilet area), where the literature mineralogical and geological data on iron mine fields were already available, and the Western Sahara (the southern flank of Tindouf Basin), which was investigated during a field campaign and was where the occurrence of an analogous sedimentary succession led us to hypothesise the possible presence of exploitable iron deposits. This work demonstrates the usefulness of multispectral imagery in the detection of iron-rich areas and establishes a full remote sensing procedure, which can be profitably applied to a wider region of Western Sahara and can provide interesting perspectives on the possibility of detecting new exploitable iron ore deposits in arid environments. © 2012 Saudi Society for Geosciences
Potential Use of Remote Sensing Techniques for Exploration of Iron Deposits in Western Sahara and Southwest of Algeria
No full textAt present, Western Sahara is politically one of the most sensitive areas of the World. Its economic development could be achieved through the exploitation of mineral resources that can be found in the almost unexplored area administrated by the Saharawi Arab Democratic Republic. In this paper, we describe applications of known and cost-effective remote sensing techniques to detect and map areas containing mineral deposits, through the enhancement of Landsat ETM+ imageries. Several image processing techniques (false color composite, band ratioing, and principal component analysis) were used to highlight the presence of iron deposits. Two test areas were selected, one in Western Sahara and another one in Algeria. The occurrence of iron deposits in these test areas was assured using literature data for the Algerian test site and through a field campaign for the Western Sahara. There is good agreement between the ground truth data and the results obtained by the enhancements of the satellite images. Landsat images can be downloaded free of charge and their enhancements does not need expensive hardware or software tools. Therefore this technology could be transferred to the Saharawi technicians, enabling them to explore and manage the mineral resources of their own country independently. © 2013 International Association for Mathematical Geology
Two GUIs-based analysis tool for spectroradiometer data pre-processing
No full textA new graphical user interface (GUI) for pre-processing reflectance spectra, built using MATLAB and expressly designed for the ASD FieldSpec® spectroradiometer, was developed to solve problems that generally affect experimental ASD data. The GUI is characterised by an easily readable, graphic visualisation of spectra, from which the absorption band depth (ABD) can be obtained for a selected wavelength. The output format of the ASD data is a binary file with an .asd extension. The binary file, that provides a single spectrum, can be processed using a software functionality, by means of a GUI, that allows to select one or more binary files to produce a spectral library in a unique .txt file. The spectral reflectance is re-calibrated with the "convex-hull" methodology to eliminate the convex shape, which is typical of reflectance spectra. Different examples of the use of the new GUI are provided. © 2013 Springer-Verlag Berlin Heidelberg
Corsica ophiolites: geochemistry and petrogenesis of basaltic and metabasaltic rocks
No full textThis paper presents a systematic geochemical characterization of the basaltic and metabasaltic rocks from the Alpine Corsica ophiolites. The various ophiolitic units of Alpine Corsica can basically be subdivided into two main types: (1) high-pressure/low-temperature, metamorphic ophiolites belonging to the Lower Schistes Lustrés (LSL) and Upper Schistes Lustrés (USL) Complexes and (2) the non-metamorphic, upper ophiolitic units.
Basaltic and metabasaltic rocks from all these units display many common geochemical characteristics, which indicate a common genesis in a mid-ocean ridge setting. However, on the bases of their high field strength element (HFSE) and rare earth element (REE) distribution, two main geochemical types can be recognized. One type has normal MORB-type (N-MORB) geochemical features, being characterized by flat N-MORB normalized HFSE patterns, slight depletion in Th, U, Ta and variable depletion of light REE (LREE) with respect to medium REE (MREE). This type is volumetrically prevalent and is found in metabasalts from the LSL and USL, as well as in basalts from the upper ophiolitic units. The other type has transitional MORB-type (T-MORB) geochemical features, as it shows slightly enriched N-MORB normalized HFSE patterns, slight enrichment in Th, U, Ta and LREE enrichment with respect to MREE. This
type is observed in metabasaltic rocks from the Santo Pietro di Tenda Unit (USL) and in basalts from the Nebbio and from the bottom of the Balagne units.
A distinguishing geochemical feature of basaltic and metabasaltic rocks from the Alpine Corsica ophiolites is a marked heavy REE (HREE) fractionation with respect to MREE. The (Sm/Yb)N ratios range from 1.1 to 2.6, but in most cases are > 1.5. This feature is interpreted as a garnet signature, which can be related to the melting of a heterogeneous mantle source characterized by garnet-bearing mafic/ultramafic layers. Semi-quantitative modelling of the REE data for the N-MORBs indicates that these rocks may have derived from small-degree (< 8%) partial melting of a depleted MORB-type peridotitic source bearing small volumes of garnet-pyroxenite relics. The differential degree of partial melting of this source can explain the significant range of variation of LREE/MREE ratios, as well as the high (Sm/Yb)N ratios observed in the studied N-MORB rocks. In addition, the N-MORB rocks most likely derived from compositionally similar mantle sources and much of the internal chemical variation in these rocks is more likely due to differential partial melting rather than different enrichments of their mantle sources. Semi-quantitative modelling of the REE data for the T-MORBs indicates that these rocks may have been derived from small-degree (< 5%) partial melting of a lithospheric mantle source bearing garnet-pyroxenite relics. They could represent products extruded in the ocean-continent transition zone during the initial stage of oceanic opening, whereas N-MORBs may represent volcanic sequences formed in more internal paleo-oceanic positions after the onset of the oceanic spreading
3-D geomechanical rock mass characterization for the evaluation of rockslide susceptibility scenarios
No full textAn integrated methodology based on traditional field and remote surveys such as terrestrial laser scanning and terrestrial infrared thermography is proposed, with the aim of defining susceptibility scenarios connected to rock slopes affected by instability processes. The proposed methodology was applied to a rock slope threatening a coastal panoramic roadway located in western Elba Island (Livorno district, central Italy). The final aim of the methodology was to obtain an accurate three-dimensional rock mass characterization in order to detect the potentially more hazardous rock mass portions, calculate their volume, and collect all the required geomechanical and geometrical parameters to perform a detailed stability analysis. The proposed approach proved to be an effective tool in the field of engineering geology and emergency management, when it is often urgently necessary to minimize survey time when operating in dangerous environments and gather all the required information as fast as possible
"The love that made hell, paradise." Ouida re-writing the Paolo and Francesca theme in Held in Bondage
No full textThe bestselling Victorian author Ouida reveals in her novels, and, in particular, Held in Bondage, an extraordinary knowledge od Dante, by using characters and themes from the Commedia. The Paolo and Francesca theme actually constitutes part of the plot of the novel and is to be found in many of her other works, short stories and non-fiction writing
HERStory Makers 2023: Francesca Fotheringham
No full textFrancesca Fotheringham is a postdoctoral research associate at the University of Edinburgh studying educational psychology with a focus on neurodiversity. She took part in HERStory Makers 2023.What is HERStory Makers?HERStory Makers is a social media competition for female-identifying early career researchers to share their research, their career journeys, and to inspire the next generation. Winners are selected by public vote. HERStory Makers is also part of EXPLORATHON, Scotland's contribution to European Researchers' Night.In 2022-23, EXPLORATHON Francescasupported by the Engineering & Physical Sciences Research Council [grant number EP/X020762/1].Author contributions to contentFrancesca conceived, planned, and recorded the video content. Kirsty Ross edited the video content to insert HERStory Maker credits, added subtitles, and reduce video length to below Twitter/X limit of 2 mins and 20 secs.</p
Medicina illuminata. La Biblioteca Lancisiana di Roma
No full textL'articolo presenta i codici miniati della Biblioteca Lancisiana di Roma. La prima parte, del coautore, è dedicata alla Biblioteca. La seconda parte, di F. Manzari, tratta dei manoscritti miniati, costituiti da due codici con le opere di Avicenna e dal Liber fraternitatis della Confraternita dell'Ospedale di Santo Spirito in Sassia a Roma.The article introduces the illuminated manuscripts of the Biblioteca Lancisiana in Rome. The first part of the article, by the co-author, is dedicated to the Library. The second part, by Francesca Manzari, illustrates the manuscipts; these are two manuscripts with the works of Avicenna and the Liber fraternitatis of the Confraternity of the Hospital of Santo Spirito in Sassia in Rome
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