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Detection of potential gold mineralization areas using MF-fuzzy approach on multispectral data / Tohid Nouri in Geocarto international, Vol 37 n° 17 ([20/08/2022])
[article]
Titre : Detection of potential gold mineralization areas using MF-fuzzy approach on multispectral data Type de document : Article/Communication Auteurs : Tohid Nouri, Auteur Année de publication : 2022 Article en page(s) : pp 5017 - 5040 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image
[Termes IGN] altération géologique
[Termes IGN] analyse des mélanges spectraux
[Termes IGN] appariement d'images
[Termes IGN] diffraction
[Termes IGN] image multibande
[Termes IGN] Iran
[Termes IGN] logique floue
[Termes IGN] mine d'or
[Termes IGN] MNS ASTER
[Termes IGN] pixel
[Termes IGN] prospection minérale
[Termes IGN] sédiment
[Termes IGN] spectrométrieRésumé : (auteur) The northeast area of Ardabil, a city located in northwestern Iran, is one of the potential gold mineralization areas. In this study, ASTER data were used to identify the alteration events in this region. For this purpose, a novel approach was used in which the fuzzy logic was implemented to extract the co-occurrence map of the endmembers. This method revealed alterations more accurately than SID. Stream sediment samples were employed to validate the obtained results. Since these samples are alluvial, their catchment basins were determined and overlaid with the alteration maps. To the best of the authors’ knowledge, this validation approach has not been used in previous studies. The extracted alteration zones were in high conformity to the stream sediment samples. Next, X-ray diffraction (XRD) analysis and field spectrometry were used for delineation of the mineralogical phases present in the anomalous areas. Finally, the potential gold mineralization zones were identified. Numéro de notice : A2022-701 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/10106049.2021.1903575 Date de publication en ligne : 07/06/2021 En ligne : https://doi.org/10.1080/10106049.2021.1903575 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=101560
in Geocarto international > Vol 37 n° 17 [20/08/2022] . - pp 5017 - 5040[article]Near-real-time identification of the drivers of deforestation in French Guiana / Marie Ballère (2021)
Titre : Near-real-time identification of the drivers of deforestation in French Guiana Type de document : Article/Communication Auteurs : Marie Ballère , Auteur ; Stéphane Mermoz, Auteur ; Alexandre Bouvet, Auteur ; Thierry Koleck, Auteur Editeur : Munich [Allemagne] : European Geosciences Union EGU Année de publication : 2021 Conférence : EGU 2021, General Assembly 19/04/2021 30/04/2021 en ligne OA Abstracts only Format : 21 x 30 cm Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de télédétection
[Termes IGN] déboisement
[Termes IGN] exploitation forestière
[Termes IGN] forêt tropicale
[Termes IGN] Guyane (département français)
[Termes IGN] image radar moirée
[Termes IGN] image Sentinel-SAR
[Termes IGN] mine d'or
[Termes IGN] surveillance forestière
[Termes IGN] urbanisationNuméro de notice : C2021-004 Affiliation des auteurs : UGE-LASTIG+Ext (2020- ) Thématique : BIODIVERSITE/FORET/IMAGERIE Nature : Communication nature-HAL : ComSansActesPubliés-Unpublished DOI : sans En ligne : https://doi.org/10.5194/egusphere-egu21-16015 Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=97598 Towards a system combining SAR and optical Sentinel data to monitor gold mining in the Guiana shield / Mathieu Rahm (2016)
Titre : Towards a system combining SAR and optical Sentinel data to monitor gold mining in the Guiana shield Type de document : Article/Communication Auteurs : Mathieu Rahm, Auteur ; Cédric Lardeux, Auteur ; Pierre-Louis Frison , Auteur ; et al., Auteur Editeur : Paris : Agence Spatiale Européenne ASE / European Space Agency ESA Année de publication : 2016 Conférence : LPS 2016, ESA Living Planet Symposium 09/05/2016 13/05/2016 Prague République tchèque programme sans actes Importance : 60 p. Format : 21 x 30 cm Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de télédétection
[Termes IGN] analyse diachronique
[Termes IGN] Brésil
[Termes IGN] déboisement
[Termes IGN] fusion d'images
[Termes IGN] Guyana
[Termes IGN] Guyane (département français)
[Termes IGN] image Sentinel-MSI
[Termes IGN] image Sentinel-SAR
[Termes IGN] mine d'or
[Termes IGN] pollution des eaux
[Termes IGN] SurinameRésumé : (auteur) Included in the larger Guiana Shield ecosystem, Suriname, Guyana, French Guiana and the Brazilian state of Amapá possess one of the largest continuous tracts of pristine forest in the world. Under little threat until fifteen years ago, deforestation and forest degradation are of increasing concern in the region. Gold mining activities driven by the sustained increase of gold price has experienced a significant boom and represents nowadays one of the main driver. The pollution of rivers and streams by mercury used in small-scale gold mining is also expanding, which increases risks to local population health and freshwater biodiversity. In 2010, the French National Forest Office (ONF) showed by using optical satellite images at medium and high resolution (HR) that gold mining activities’ impacts on forest cover and freshwater increased approximately by a factor three in the region between 2001 and 2008. More recently, Alvarez-Berríos et al. (2015) pointed out a sustained acceleration of deforestation caused by gold mining in the Guiana shield between 2007 and 2013. However, this study which was performed using low resolution data at the scale of South America has limited capacity to detect gold mining, especially in the high forest cover of Guiana Shield where small- and medium-scale operations account for most of the deforestation. To overcome this limitation, the REDD+ for the Guiana Shield project conducted a study co-funded by WWF Guianas to update for 2014 the ONF 2001-2008 results, using optical multi-sensors data at medium and high resolution. The study was carried out following a unique collaborative and participatory approach involving a team of experts from the forestry and environmental services of each territory, namely SEMA (Amapá-Brazil), ONF (French Guiana-France), GFC (Guyana), and SBB (Suriname). The results confirmed the rapid expansion of the activity in the region where more than 92,000 ha were newly deforested between 2008 and 2014, compared to approximately 46,000 ha during the period 2001-2008. In 2014, more than 9,000 km of waterways were in direct contact with mining sites, which is approximately 6.5 times more than in 2001. Although a reliable, accurate and robust regional methodology has been developed and operationally implemented, the frequent and widespread cloud cover of the Guianan moist forest region represents a challenge for the use of optical HR data. The need to process time series of satellite images in most areas to reduce cloud cover is time-consuming. Despite processing more than two hundreds images, 3.6% of the study area remained masked by clouds. The recent free access to SAR HR Sentinel-1 data offers great opportunities to improve the process. SAR sensors can peer through clouds and their sensitivity to soil moisture can help to better detect small-scale mining sites. Therefore, the REDD+ for the Guiana Shield project has started to build capacities in the region on SAR image interpretation and processing using the Sentinel Application Platform (SNAP). A first mosaic of Sentinel-1 data covering Suriname, Guyana, French Guiana and the Brazilian state of Amapá has been created and automated pre-processing steps have been developed. The integration of Sentinel-1 data in the regional gold mining monitoring system has been successfully tested in four study sites, one in each country. The coming free access to optical HR Sentinel-2 data opens even more perspectives towards the development of cost-effective monitoring systems in the region, especially valuable in the context of REDD+. This paper first presents the results of the impact of gold mining activities on the forest cover and freshwater for 2014 and shows the evolution since 2001. Secondly, it provides the first outcomes towards the development of time- and cost-efficient forest monitoring systems in the region. Numéro de notice : C2016-058 Affiliation des auteurs : LASTIG MATIS+Ext (2012-2019) Thématique : IMAGERIE Nature : Communication nature-HAL : ComAvecCL&ActesPubliésIntl DOI : sans En ligne : http://lps16.esa.int/page_session187.php#1306p Format de la ressource électronique : URL abstract Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=91912 Documents numériques
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