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1.
Feizollah Masoumi Taymour Eslamkish Mehdi Honarmand Ali Akbar Abkar 《Journal of the Indian Society of Remote Sensing》2017,45(6):1039-1055
This study attempts to evaluate the capability of the advanced spaceborne thermal emission and reflection radiometer (ASTER) and the advantages of ground knowledge for generating maps portraying hydrothermally altered areas in relation to porphyry copper deposits. The northern part of the Rabor area in the Urumieh–Dokhtar magmatic belt, containing some copper mineralization occurrences, was investigated as a case study. Several image processing techniques, namely minimum noise fraction, pixel purity index, and n-dimensional visualization, contributed to the extraction of pure pixels as endmembers. The spectra of some rock samples collected around the well-known altered zones of the study area were resampled to ASTER bands and used to identify the image-extracted endmembers. Spectral analysis of the endmembers and ground sample spectra led to the identification of three types of hydrothermal alterations: (1) phyllic, (2) propylitic, and (3) argillic. The identified endmembers were used as the specified targets for mapping hydrothermal alteration zones over the study area by using a mixture tuned match filtering algorithm. Results demonstrate that high abundances within pixels correspond closely to the altered areas. Field observations, thin section, and X-ray diffraction of collected samples confirmed the accuracy of the alteration maps prepared by the application of the proposed methods. The final classified hydrothermal alteration maps showed the overall accuracy and kappa coefficient values of 85.41 and 0.72%, respectively. These results ascertain that ASTER data that use suitable image processing techniques appear consistent in mapping out the distribution of hydrothermally altered areas. In addition, ground knowledge data can act as a valuable information source to increase the image classification accuracy and reliability. 相似文献
2.
This work presents the promising application of three variants of TOPSIS method (namely the conventional, adjusted and modified versions) as a straightforward knowledge-driven technique in multi criteria decision making processes for data fusion of a broad exploratory geo-dataset in mineral potential/prospectivity mapping. The method is implemented to airborne geophysical data (e.g. potassium radiometry, aeromagnetic and frequency domain electromagnetic data), surface geological layers (fault and host rock zones), extracted alteration layers from remote sensing satellite imagery data, and five evidential attributes from stream sediment geochemical data. The central Iranian volcanic-sedimentary belt in Kerman province at the SE of Iran that is embedded in the Urumieh–Dokhtar Magmatic Assemblage arc (UDMA) is chosen to integrate broad evidential layers in the region of prospect. The studied area has high potential of ore mineral occurrences especially porphyry copper/molybdenum and the generated mineral potential maps aim to outline new prospect zones for further investigation in future. Two evidential layers of the downward continued aeromagnetic data and its analytic signal filter are prepared to be incorporated in fusion process as geophysical plausible footprints of the porphyry type mineralization. The low values of the apparent resistivity layer calculated from the airborne frequency domain electromagnetic data are also used as an electrical criterion in this investigation. Four remote sensing evidential layers of argillic, phyllic, propylitic and hydroxyl alterations were extracted from ASTER images in order to map the altered areas associated with porphyry type deposits, whilst the ETM+ satellite imagery data were used as well to map iron oxide layer. Since potassium alteration is generally the mainstay of porphyry ore mineralization, the airborne potassium radiometry data was used. The geochemical layers of Cu/B/Pb/Zn elements and the first component of PCA analysis were considered as powerful traces to prepare final maps. The conventional, adjusted and modified variants of the TOPSIS method produced three mineral potential maps, in which the outputs indicate adequately matching of high potential zones with previous working and active mines in the region. 相似文献
3.
Kaveh Pazand Jamal Fereidoni Sarvestani M. Reza S. Ravasan 《Journal of the Indian Society of Remote Sensing》2013,41(2):379-389
The Ahar area is located in East Azarbaijan province, and covers an area of about 2,500 km2. Spectral mapping techniques were applied on VNIR and SWIR of ASTER data for discriminating between hydrothermal alteration zones and the identification of high potential mineralized lithological unit associated with hydrothermal porphyry copper mineralization in the Ahar. In this research to remove atmospheric and topographic effects from ASTER data, the log-residual method (LRM) was used. Four methods, Relative Band Depth Ratios (RBD), Principal Component Analysis (PCA), Minimum Noise Fraction (MNF) and matched filtering (MF), were used to processing and interpretation of remote sensing data in the study area. Results show that ASTER images provide preliminary mineralogy information and geo-referenced alteration maps at low cost and with high accuracy for reconnaissance porphyry copper mineralizations. 相似文献
4.
Melanie Brandmeier 《国际地球制图》2013,28(8):629-648
A combined approach to detect hydrothermal alteration zones and their mineral distribution is proposed for a relatively remote area around the Carhuarazo volcanic complex in southern Peru encompassing 2222 km2. In this region, tertiary volcanic structures associated with hydrothermal alteration are well known to host epithermal ore deposits. We make an attempt to detect and to quantify alteration minerals based on spectral analysis using ASTER reflectance data product provided by LP-DAAC. Besides commonly used ratio images, mineral indices (MI) and relative band depth images (RBD), we also extracted endmember spectra using Pixel-Purity-Processing preceded by minimum noise fraction transformation. These spectra are thought to represent the spectrally purest pixel of the image and show the typical absorption features of the main constituents. Based on this assumption, we used different spectral analysis methods in order to extract the most important alteration minerals for such an environment. These minerals were then used for matched filter processing in areas showing high values in MIs and RBDs. Using this method, we detected and mapped argillic alteration and variations in the distribution of important minerals like alunite, kaolinite or nacrite. There were no indications for the presence of propilitization at ASTER spatial resolutions. Our method can be applied easily to any ASTER scene and provides information about the intensity of alteration and the character of alteration zones. The intensity is highest in the centre of the Carhuarazo volcanic complex and is mostly argillic with a high content of alunite, dickite and other clay minerals. 相似文献
5.
6.
AbstractRemote sensing techniques provide meaningful information to mineral exploration by identifying the hydrothermally altered minerals and the fracture/fault systems. In this article, Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) data were processed to detect the hydrothermal alteration zones in Hamama area in the central part of the Eastern Desert of Egypt. Band ratios and principal component analyses successfully revealed the extent and the geometry of the hydrothermal alteration zones that trend in an NE–SW direction. Matching pixel spectrum derived from Minimum Noise Fraction, Pixel Purity Index, and n-dimensional visualization with reference spectra allowed characterizing key hydrothermal alteration minerals, including chlorite, kaolinite-smectite, muscovite, and haematite, in a successive alteration pattern. Field investigations and X-Ray Diffraction analysis validated the results revealed by ASTER data. In addition, the present prospects of significant gold and massive sulphide mineralizations are consistent with the detected hydrothermal alteration zone. 相似文献
7.
8.
Zahra Yazdi Alireza Jafari Rad Mehraj Aghazadeh Peyman Afzal 《Journal of the Indian Society of Remote Sensing》2018,46(10):1581-1593
The Sonajeel prospect is located in the Arasbaran belt which is one of the significant copper mineralization belts in NW Iran. There are mostly Eocene volcano-sedimentary rocks and Post Eocene intrusive units which are the source for mineralization in the area. ASTER multispectral images were used for delineation of alteration zones as a key feature of porphyry copper mineralization. Due to the need for geometric correction and ortho-rectification of the ASTER images, a high resolution QuickBird image with pixel width of about 60 cm (in PAN) was employed as a reference image in order to boost the rectification process. Ortho-rectification has been done by using digital elevation model which is created by topographic map in scale 1:1000. Potassic alteration as one of the essential alteration types in porphyry copper deposits, distributed mostly in the north of the Sonajeel prospect that determined by Thermal infrared bands processing. Phyllic and argillic alteration zones detected by creating relative absorption band-depth grids which are comparable to field observations. Moreover, silica rich areas which are remnants of hydrothermal circulation and form at the top of porphyry copper systems were detected for recognition of epithermal deposits (with 1 km distance from Sonajeel porphyry system). Finally, Remote Sensing results were compared by field evidences especially for determination of an epithermal system. Most parts of the alteration zones were observed of the surface confirmed with the remote sensing alteration (in average about 75% matched fittingly), displayed concentrations anomalous in the NE and NW parts of the studied area. 相似文献
9.
基于ASTER数据的蚀变矿物信息提取——以哈密黄山铜镍矿区为例 总被引：1，自引：0，他引：1
在分析哈密黄山铜镍矿区典型地物波谱特征的基础上,设计了基于ASTER数据的蚀变信息提取流程,详细论述了对4组含不同离子或基团的常见蚀变矿物应用主成分分析(PCA)进行蚀变信息提取、采用光谱角制图法(spectral angle mapper,SAM)进行干扰异常筛选的“SAM去干扰异常主分量门限技术”.4组(9种)蚀变矿物包括:含Fe离子的矿物(针铁矿、赤铁矿)、含CO23-基团的矿物(方解石、白云石)、含Al - OH基团的矿物(白云母、蒙脱石、高岭石)以及含Mg - OH基团的矿物(绿泥石、绿帘石).蚀变矿物信息提取结果表明,“SAM去干扰异常主分量门限技术”方法可行,对ASTER数据的应用效果与实际情况比较吻合,充分证明ASTER在短波红外范围内具有很强的矿物刻画能力. 相似文献
10.
矿化蚀变信息的提取是遥感找矿中重要的内容,ASTER遥感数据因波段范围宽、波段多,在蚀变异常与矿产勘探中有较好的应用前景。本文在比较了前人的研究方法,如比值法、主成分分析法、光谱角法基础上,通过对西藏朱诺矿区进行试验研究,得出了在该研究区采用主成分分析法最佳的结论。 相似文献
11.
Murat Gül Kemal Gürbüz Özgür Kalelioğlu 《Journal of the Indian Society of Remote Sensing》2012,40(2):257-269
The Kahramanmaraş Foreland Basin (KFB) margins are formed by Paleozoic-Mesozoic limestone, metamorphic and ophiolite. This
basin contains sandstone and claystone alternations with lesser amounts of reefal limestone, channelized conglomerates, debrites
and slump deposits. An irregular topography and absence of path obscured the accurate and complete mapping of the basin. Thus,
Landsat TM images were used. The RGB 751 false colour composites were chosen due to abundant claystone and limestone content
of the KFB. The RGB PCA 145 was preferred due to high loading of TM bands 5 (clay and iron oxide mineral), 7 (carbonate mineral),
3 and 1 (albedo and topography). The RGB 5/7-5/1-4 (light green dots in 5/7 indicate enhanced claystone area and OH- bearing alteration zone; red dots in 5/1 indicate enhanced iron oxide bearing alteration zone; fourth band for water bearing
minerals) shows the transportation way of sediments. The OH- and iron oxide bearing alteration zones are found on older source rocks and younger deposition area. Main lithological boundary,
geometry and provenance properties of the KFB were satisfactorily obtained from the Landsat TM images. However, low spatial
resolution (30 m) prevents detail facies discrimination that still requires hard field working and/or detailed satellite images. 相似文献
12.
Concealed and fossilized geothermal systems are not characterized by obvious surface manifestations like hotsprings and fumaroles, therefore, could not be easily identifiable using conventional techniques. In this investigation, the applicability of Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) and Hyperion data-sets were evaluated in discriminating hydrothermal alteration minerals associated with geothermal systems as a proxy in identifying subtle Geothermal systems at Yankari Park, Nigeria. Feature-oriented principal component selection, spectral angle mapper, linear spectral unmixing were applied to ASTER data based on spectral characteristics of hydrothermal alteration key minerals for a systematic selective extraction of the information of interest. Analytical imaging and geophysics-developed processing methods were applied to Hyperion data for mapping iron oxide/hydroxide minerals and clay mineral assemblages in hydrothermal alteration zones. The results indicate that ASTER and Hyperion could be complemented for reconnaissance stage of targeting subtle alteration mineral assemblages associated with geothermal systems. 相似文献
13.
AbstractThe Shahr-e-Babak region located in the Kerman metallogenic belt is one of the high potential segments of Urumieh–Dokhtar magmatic arc for porphyry copper and epithermal gold mineralization in the south of Iran. This high potential zone encompasses several porphyry copper deposits under exploitation, development and exploration stages. The aim of this study is to evaluate Landsat-8 data and comparison with the Advanced Spaceborne Thermal Emission and Reflection Radiometer data-sets for mapping hydrothermal alteration zones related to Cenozoic magmatic intrusions in Shahr-e-Babak region. Previous studies have proven the robust application of ASTER in lithological mapping and mineral exploration; nonetheless, the Landsat-8 data have high capability to map and detect hydrothermal alteration zones associated with porphyry copper and epithermal gold mineralization. In this investigation, several band combinations and multiplications, developed selective principal component analysis and image transformations were developed for discriminating hydrothermal alteration zones associated with porphyry copper mineralization using Landsat-8 data. 相似文献
14.
为了利用遥感影像进行更加精确的找矿预测,本文选择新疆东天山尾亚地区ASTER数据进行矿化蚀变信息提取方法研究。为了提高信息提取精度,本文提出了结合主成分分析(PCA)、多尺度分割和支持向量机(SVM)的遥感矿化蚀变信息提取方法。首先,分析ASTER数据的特征,选取各矿化蚀变信息的特征波段,对组合波段进行主成分分析,获得主分量图像;然后,对各主分量图像进行多尺度分割,并获得分割之后的均值图像;接着,提取训练样本,利用SVM对训练样本进行训练,采用试验方法求得最优核参数和松弛变量,构造最优SVM模型;最后,运用最优SVM模型完成矿化蚀变信息的提取。进行主成分分析时,铁染蚀变信息选择Band1、2、3、4组合,Al-OH基团蚀变信息选择Band 1、4、6、7组合,OH和CO32-基团蚀变信息采用Band 1、2、8、9组合。在运行SVM时采用了序列最小优化算法(SMO)进行求解,速度提高了12%。实验结果表明,与波段比值法、主成分分析法及基于光谱角和SVM的方法等3种方法相比,本文方法提取铁染蚀变信息、Al-OH基团蚀变信息及OH和CO32-基团蚀变信息的总体精度可达到87.98%、 90.01%及88.93%,Kappa系数分别为0.8011、0.8134及0.8023,与成矿区带、已知矿点和已有不同地质背景成矿特征相关性较好。 相似文献
15.
In this study, we proposed an automated lithological mapping approach by using spectral enhancement techniques and Machine Learning Algorithms (MLAs) using Airborne Visible Infrared Imaging Spectroradiometer-Next Generation (AVIRIS-NG) hyperspectral data in the greenstone belt of the Hutti area, India. We integrated spectral enhancement techniques such as Principal Component Analysis (PCA) and Independent Component Analysis (ICA) transformation and different MLAs for an accurate mapping of rock types. A conjugate utilization of conventional geological map and spectral enhancement products derived from ASTER data were used for the preparation of a high-resolution reference lithology map. Feature selection and extraction methods were applied on the AVIRIS-NG data to derive different input dataset such as (a) all spectral bands, (b) shortwave infrared bands, (c) Joint Mutual Information Maximization (JMIM) based optimum bands, and (d) optimum bands using PCA, to choose optimum input dataset for automated lithological mapping. The comparative analysis of different MLAs shows that the Support Vector Machine (SVM) outperforms other Machine Learning (ML) models. The SVM achieved an Overall Accuracy (OA) and Kappa Coefficient (k) of 85.48% and 0.83, respectively, using JMIM based optimum bands. The JMIM based optimum bands were more suitable than other input datasets to classify most of the lithological units (i.e. metabasalt, amphibolite, granite, acidic intrusive and migmatite) within the study area . The sensitivity analysis performed in this study illustrates that the SVM is less sensitive to the number of samples and mislabeling in the model training than other MLAs. The obtained high-resolution classified map with accurate litho-contacts of amphibolite, metabasalt, and granite can be coupled with an alteration map of the area for targeting the potential zone of gold mineralization. 相似文献
16.
AbstractGeological mapping is one of the primary tasks of remote sensing. Remote sensing applications are especially useful when extreme environmental conditions inhibit direct survey such as in Antarctica. In this investigation, a satellite-based remote sensing approach was used for mapping alteration mineral zones and lithological units using Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) data in the Oscar II coast area, north-eastern Graham Land, Antarctic Peninsula. Specialized band ratios and band combinations were developed using visible and near infrared, shortwave infrared (SWIR) and thermal infrared spectral bands of ASTER for detecting alteration mineral assemblages and lithological units in Antarctic environments. Constrained Energy Minimization, Orthogonal Subspace Projection and Adaptive Coherence Estimator algorithms were tested to ASTER SWIR bands for detecting sub-pixels’ abundance of spectral features related to muscovite, kaolinite, illite, montmorillonite, epidote, chlorite and biotite. Results indicate valuable applicability of ASTER data for Antarctic geological mapping. 相似文献
17.
ASTER和TM/ETM+遥感数据融合监测土地覆盖变化 总被引：3，自引：0，他引：3
在人们纷纷选择IKONOS、QUICKBIRD、SPOT-5等高分辨率影像监测土地利用/覆盖变化之际,以北京海淀区为例,尝试采用Brovey变换和主成分分析(PCA)法融合ASTER、TM/ETM+中等分辨率影像,充分利用ASTER、TM/ETM+数据的多光谱和较高空间分辨率特性,挖掘其在土地覆盖变化监测中的潜力,为大规模监测土地利用/覆盖变化提供科学参考。研究将2003年ASTER多光谱3N、2、1波段与1999年ETM+PAN波段进行Brovey变换;1992年TM543与1999年ETM+PAN波段进行PCA融合,快速发现土地覆盖变化信息。经验证,变化发现精度达92.50%,符合项目精度要求。试验表明:在缺乏高分辨率影像的地区,选择价格相对便宜的AS-TER和TM/ETM+数据,采用Brovey变换和主成分分析(PCA)法进行融合,可有效监测土地覆盖变化,节约动态监测成本,二者具有很大的应用价值,值得推广。 相似文献
18.
ASTER short-wave infrared bands were used to investigate the spectral discrimination of hydrothermally altered materials, based on the presence of minerals with diagnostic spectral features in wavelengths around 2200 nm (e.g. kaolinite and K-micas). Due to the presence of widespread albitized-greisenized materials, the Serra do Mendes granitoid, located in area of tropical savannah environment in Central Brazil, was selected for this study. The Spectral Angle Mapper (SAM) technique was used as an attempt to detect the presence of hydroxyl-bearing minerals in the domain of the hydrothermally altered materials. Results indicated that areas of altered materials were discriminated from the surrounding mainly due to the high overall reflectance of the whitish lithosols in these areas. The detection of hydroxyl-bearing minerals was blurred by the presence of a sparse grass cover in the alteration zone, which caused a slight increase in the SAM classification angles. As a consequence, the remote detection of hydroxyl-bearing minerals was restricted to a small number of pixels from barren areas. Results indicate that, for the environmental conditions of the study area, ASTER data are more efficacious for spectral characterization of rock–soil-vegetation associations than for the detection of alteration-derived minerals. 相似文献
19.
Habes A. Ghrefat Abdullah A. Al Zahrani Mahmoud A. Galmed 《Journal of the Indian Society of Remote Sensing》2018,46(9):1399-1411
Mapping the surficial extent of oolitic iron ore deposits hosted in the Oligo–Miocene sedimentary rocks of the Ashumaysi Formation, western Saudi Arabia, was carried out using Landsat 7 Enhanced Thematic Mapper Plus (ETM+) data. Ore samples were collected from four various locations in the study area, and were studied in the laboratory using the GER 3700 Spectroradiometer (0.4–2.5 µm) and X-ray diffraction (XRD). Principal component analysis (PCA), minimum noise fraction (MNF), and minimum distance classification were used and assessed to map mineralization zones in the study area. Good correspondences were observed between the results obtained from the above mentioned techniques, spectral reflectance analyses, and XRD. The confusion matrix results revealed that mapping of iron ores using MNF is better and more accurate than using PCA. Good matching was also observed between the spectral reflectance curves of the collected samples and the corresponding pixels from Landsat 7 ETM+. The results demonstrated the usefulness of the image processing and interpretation of Landsat 7 ETM+ data for the detection and delineation iron ore deposits in arid and semi-arid areas. 相似文献
20.
Banana is one of the main economic agrotypes in Zhangzhou, Fujian Province. The multi-temporal ENVISAT ASAR data with different
polarization are used to classify the banana fields in this paper. Principal component analysis (PCA) was applied for six
pairs of ASAR dual-polarization data. For its large leaves, banana has high backscatter. So the value of banana fields is
high and shows very bright in the 1st component, which makes it much easier for banana fields extraction. Dual-polarization
data provide more information, and the VV and VH backscatter of banana show different characters with other land covers. Based
on the analysis of the radar signature of banana fields and other land covers and the 1st component, banana fields are classified
using object-oriented classifier. Compared to the field survey data and ASTER data, the accuracy of banana fields in the study
area is 83.5%. It shows that the principal component analysis provides the useful information in SAR images analysis and makes
the extraction of banana fields easier.
Supported by the Program for New Century Excellent Talents in University (NCET-05-0573), Fujian Science and Technology Project
(No.2006I0018), the Science Project of the Education Department of Fujian Province(No. 2006F5022). 相似文献