scholarly journals Use of the Sentinel-2A Multispectral Image for Litho-Structural and Alteration Mapping in Al Glo’a Map Sheet (1/50,000) (Bou Azzer–El Graara Inlier, Central Anti-Atlas, Morocco)

2019 ◽  
Vol 54 (3) ◽  
pp. 73-96
Author(s):  
Abdessamad El Atillah ◽  
Zine El Abidine El Morjani ◽  
Mustapha Souhassou
Keyword(s):  
Hydrothermal Alteration ◽  
Thermal Emission ◽  
Principal Component ◽  
Alteration Zone ◽  
Efficient Manner ◽  
Geological Maps ◽  
Analysis Technique ◽  
Landsat 7 ◽  
Earth Observation Satellites ◽  
Sentinel 2A

Abstract The discovery of natural resources remains the main mission of Earth observation satellites, especially in geographical areas that have a very difficult accessibility as those of the Bou Azzer–El Graara inlier (Central Anti-Atlas, Morocco). This work investigates the use of different satellite data, such as Sentinel-2A’s multispectral imagery, in order to direct the prospection program in an efficient manner, saving both time and cost. The image processing methods of Landsat 7, 8, and “Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER)” (30 m/15 m) were used to create methods for Sentinel-2A images (10 m). The red, green, blue (RGB) image 12.8.2, 11/12.11/2.11/8, principal component (PC) 1,2,3(11.12.2), and other new images were the result of principal component analysis (PCA), and classification by the Iterative Self-Organizing Data Analysis Technique (ISODATA) and K-Means allowed realization of a lithological cartography as well as maps of lineaments through directional filters and the ratio of 11/12 for hydrothermal alteration zone mapping. The assembly of lithological, structural, and hydrothermal alteration data gave an idea of the mineralogy of the study area. Validity of the results was tested by comparison with the field data and the geological maps of the studied site (62% for the hydrothermal alteration zone, 81% for the lithological map, and 74% for the structural map).

scholarly journals Utilisation De L’image Multispectrale Pour L’exploration Et La Recherche Des Ressources Minérales : État Des Connaissances Et Proposition D’un Modèle De Traitement

2018 ◽  
Vol 14 (24) ◽  
pp. 350
Author(s):  
Abdessamad El Atillah ◽  
Zine El Abidine El Morjani ◽  
Mustapha Souhassou
Keyword(s):  
Remote Sensing ◽  
Principal Component ◽  
Geological Mapping ◽  
Landsat 8 ◽  
Geological Maps ◽  
Landsat 7 ◽  
Sentinel 2A ◽  
Terrestrial Globe ◽  
The Cost ◽  
Methods Of Treatment

Multiband space remote sensing is an indirect tool for prospecting the Earth's surface. It is very powerful especially in its applications related to the field of geology including geological mapping, mining and oil exploration. It can also significantly reduce the cost of exploration, reach inaccessible areas, guide mining research to favorable regions and reach a large surface. In this article, we highlight in details the state of knowledge in this field of research by citing the different methods and approaches carried out by several specialists who generally define the use of remote sensing for lithostructural and mineralogical mapping and particularly for the exploration and research of mineral substances. We also create methods derived from the aforementioned methods of treatment by means of a logical analogy between the different bands of several satellites of observation of the terrestrial globe, particularly between : Landsat 7 ETM +; Landsat 8 OLI / TIRS; Aster and Sentinel 2A. At the end, we synthesize these results by proposing a multispectral image-processing model that can be applied directly. This model starts with the calculation of Optimum Index Factor (OIF), which allows us to detect only the most important colored composites; and the reports of the bands, rations, the principal component analysis, ACI and the classification that allow the realization of a lithological and mineralogical mapping as well as maps of lineaments by means of directional filters. The validity of the models is tested by comparison with field data and geological maps of the studied site.

scholarly journals IDENTIFICATION OF ROCKS AND THEIR QUARTZ CONTENT IN AMARKANTAK, INDIA USING ASTER TIR DATA

2018 ◽  
Vol XLII-5 ◽  
pp. 255-259 ◽  
Author(s):  
S. Guha ◽  
H. Govil ◽  
M. Tripathi ◽  
M. Besoya
Keyword(s):  
Thermal Emission ◽  
Mineral Exploration ◽  
Atmospheric Correction ◽  
Sedimentary Rocks ◽  
Interaction Strength ◽  
Principal Component ◽  
Quartz Content ◽  
Important Indicator ◽  
Analysis Technique ◽  
Organic Particles

<p><strong>Abstract.</strong> Quartz (SiO<sub>2</sub>) abundance in rock is an important indicator of mineralization in many metal deposits and quartz detection has a great role in mineral exploration. The present study identified the quartz contained rocks in Amarkantak region, India applying thermal infrared bands (bands 10–14) of the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) image. After atmospheric correction, principal component analysis technique was applied on the TIR bands and the resulting principal component images were analyzed. The three optimal principal components were selected based on the spectral interaction strength and the eigenvalues of each band of the ASTER data. The result presented that extrusive igneous rock and carbonate sedimentary rocks are quartz-poor while sedimentary rocks made up of organic particles and sandstone is quartz-rich.</p>

Detection of slip surface in earth slide based on mineral assemblages -An example of hydrothermal alteration zone landslide in East Hokkaido Japan-

2014 ◽  
Vol 51 (3) ◽  
pp. 106-112
Author(s):  
Hiroyuki MAEDA ◽  
Masanori KOHNO ◽  
Yoshihiko SEKISHITA ◽  
Satoshi UEMATSU ◽  
Hiroshi NAYA
Keyword(s):  
Hydrothermal Alteration ◽  
Slip Surface ◽  
Alteration Zone ◽  
Mineral Assemblages

ANALYSIS OF AIRBORNE SPECTRORADIOMETRIC DATA AND THE USE OF LANDSAT DATA FOR MAPPING HYDROTHERMAL ALTERATION

Geophysics ◽  
1978 ◽  
Vol 43 (5) ◽  
pp. 967-987 ◽  
Author(s):  
William Collins
Keyword(s):  
Hydrothermal Alteration ◽  
Spectral Resolution ◽  
Spectral Properties ◽  
Ferric Iron ◽  
Correlated Data ◽  
High Spectral Resolution ◽  
Alteration Zone ◽  
Landsat Data ◽  
Spectral Contrast ◽  
Aircraft Data

An airborne spectroradiometer system has been developed to take 500 channel ground target measurements simultaneously in the spectral region between 400 and 1100 nm. Survey flights with the instrument over an exposed hydrothermal alteration zone in Goldfield, Nevada provide the high‐spectral resolution and spatially correlated data necessary to establish a computerized technique for spectral discrimination of limonitic zones that could indicate mineralization. The data generated by the airborne system are used, in particular, to determine the spectral properties of alteration materials as they appear in integrated measurements over extended field areas, to determine which spectral properties are unique under field conditions and will remain unique in the low‐spectral resolution Landsat data, and to determine accurately the nature and magnitude of the relative spectral differences among geologic targets under the broadband configuration. Field measurements from the aircraft are spatially integrated over contiguous 18 m square fields‐of‐view along traverses flown to cover both background and altered rock assemblages. A small spectral signal unique to zones enriched in ferric iron minerals is recoverable in the aircraft data. Based on a differential spectral discriminant, a computer‐compatible method has been devised to extract the ferric iron signal from atmospheric and background terrain and geologically induced variations in Landsat data. The discrimination technique, adapted to satellite spectral data, was applied to the Goldfield region, including the area of known alteration and metallic mineralization. Field reconnaissance and comparison with published maps for this region has affirmed that limonitic alteration is reliably delineated by the computer analysis technique. Assessment of current satellite instrumentation based on the aircraft data analysis indicates that inclusion of more appropriate band‐pass regions in future sensors could increase spectral contrast among geologic targets by 100 percent. Reducing the field‐of‐view can also increase spectral contrast, and can help reduce spectral ambiguities among extended targets.

scholarly journals Hyperspectral monitoring of fructose content in marzipan

2018 ◽  
Vol 14 (s1) ◽  
pp. 79-88
Author(s):  
Katalin Badak-Kerti ◽  
Szabina Németh ◽  
Andreas Zitek ◽  
Ferenc Firtha
Keyword(s):  
Principal Component Analysis ◽  
Spatial Distribution ◽  
Spectral Properties ◽  
Oil Content ◽  
Sugar Content ◽  
Principal Component ◽  
Reducing Sugar ◽  
Hyperspectral Data ◽  
Hyperspectral Images ◽  
Analysis Technique

In our research marzipan samples of different sugar to almond paste ratios (1:1, 2:1, 3:1) were stored at 17 °C. Reducing sugar content was measured by analytical method, texture analysis was done by penetrometry, electric characteristics were measured by conductometry and hyperspectral images were taken 6–8 times during the 16 days of storage. For statistical analyses (discriminant analysis, principal component analysis) SPSS program was used. According to our findings with the hyperspectral analysis technique, it is possible to identify how long the samples were stored (after production), and to which class (ratio of sugar to almond) the sample belonged. The main wavelengths which gave the best discrimination results among the days of storage were between 960 and 1100 nm. The type of the marzipan was easy to distinguish with the hyperspectral data; the biggest differences were observed at 1200 and 1400 nm, which are connected to the first overtone of C-H bound, therefore correlate with the oil content. The spatial distribution of penetrometric, electric and spectral properties were also characteristic to fructose content. The fructose content of marzipan is difficult to measure by usual optical ways (polarimetry, spectroscopy), but since fructose is hygroscopic, the spatial distribution of spectral properties can be characteristic.

scholarly journals Glacier Changes in the Chhombo Chhu Watershed of Tista basin between 1975 and 2018, Sikkim Himalaya, India

2021 ◽  
Author(s):  
Arindam Chowdhury ◽  
Milap Chand Sharma ◽  
Sunil Kumar De ◽  
Manasi Debnath
Keyword(s):  
Large Population ◽  
Eastern Himalaya ◽  
Glacier Area ◽  
Change Analysis ◽  
Sikkim Himalaya ◽  
Mountain Communities ◽  
Area Loss ◽  
Landsat 7 ◽  
Landsat 5 Tm ◽  
Sentinel 2A

Abstract. Glaciers of the Tista basin represent an important water resource for mountain communities and large population downstream. The present article attempts to assess the observable changes in the glacier area in the Chhombo Chhu Watershed (CCW) of Tista basin, Sikkim Himalaya. The CCW consists of 74 glaciers (>0.02 km2) with a mean glacier size of 0.61 km2. The change of such glacier outlines obtained from the declassified hexagon KH-9 (1975), Landsat 5 TM (1989), Landsat 7 ETM+ (2000), Landsat 5 TM (2010), and Sentinel 2A (2018). The total glacier area in 1975 was 62.6 ±0.7 km2; by 2018, the area had decreased to 44.8 ±1.5 km2, an area loss of 17.9 ± 1.7 km2 (0.42 ± 0.04 km2 a−1). Debris free glaciers exhibit more area loss by 11.8 ± 1.2 km2 (0.27 ± 0.03  km2 a−1) followed by partially debris-covered (5.0 ± 0.4 km2 or 0.12 ± 0.01 km2 a−1) and maximum debris-covered (1.0 ± 0.1 km2 or −0.02 ± 0.002 km2 a−1) glaciers. The quantum of glacier area loss in the CCW of Sikkim Himalaya took its pace during 2000–2010 (0.62 ± 0.5 km2 a−1) and 2010–2018 (0.77 ± 0.6 km2 a−1) timeframes. Field investigations of selected glaciers and climatic records also support the trend in glacier recession in the CCW due to a significant increase in temperature trend and more or less static precipitation since 1995. Glacier retreat rates in the CCW were almost similar to the Changme Khangpu basin and other selected glaciers in Sikkim Himalaya. This glacier inventory and area change analysis will provide valuable information to the glaciological and hydrological community to model and plan the water resources in the Sikkim state of Eastern Himalaya. The dataset is now available from the Zenodo web portal: http://doi.org/10.5281/zenodo.4457183 (Chowdhury et al., 2021).

scholarly journals The southern Jê and adaptation to the wetland areas on the southern of the Araucarias plateau/Brazil

2021 ◽  
Vol 12 (3) ◽  
pp. 737-747
Author(s):  
Jones Fiegenbaum ◽  
Marina Schmidt Dalzochio ◽  
Eduardo Périco ◽  
Neli Teresinha Galarce Machado
Keyword(s):  
Principal Component Analysis ◽  
Sea Level ◽  
Principal Component ◽  
Interdisciplinary Studies ◽  
Archaeological Sites ◽  
Archaeological Research ◽  
Human Relations ◽  
Running Water ◽  
Analysis Technique ◽  
The Right

The Jê archeology has witnessed in the last decades a significant increase in information on the pattern of settlement, subsistence, mobility and ceremonial practices as a result of major projects developed in the South Brazilian Plateau. With the beginning of a systemic and procedural view in archeology, interdisciplinary studies in archaeological research are directed to the study on the understanding of human relations with the environment. Between the basins of the Forqueta and Guaporé Rivers, both tributaries of the right bank of the Taquari/Antas River, twenty-one archaeological sites were found with the presence of pit houses associated with Jê groups. Of the twenty-one areas of identified pit houses, nineteen are in areas close to wetlands. In an interdisciplinary perspective, we seek to understand the reasons why Jê groups established settlements close to wetlands. Six criteria were analyzed regarding the installation of pit houses and the proximity to wetlands, namely hydrography, distance from rivers with running water, clinography, terrain slope, hypsometry, altitude in relation to sea level, soils, soil quality, distance from wetlands, and phytoecological region (vegetation cover). The patterns of occupation of Jê groups were analyzed using the Principal Component Analysis technique on the variables presented.

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