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A Comparative Study of Landsat‐7 and Landsat‐8 Data Using Image Processing Methods for Hydrothermal Alteration Mapping 
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下载免费PDF全文 Feizollah Masoumi Taymour Eslamkish Mehdi Honarmand Ali Akbar Abkar 《Resource Geology》2017,67(1):72-88
Comparing spaceborne satellite images of Landsat‐8 Operational Land Imager (OLI) and Landsat‐7 Enhanced Thematic Mapper plus (ETM+) was undertaken to investigate the relative accuracy of mapping hydrothermal alteration minerals. The study investigated the northern part of Rabor, which contains copper mineralization occurrences, and is located in the Kerman Cenozoic magmatic assemblage (KCMA), Iran. Image processing methods of band ratio, principal component analysis (PCA), and spectral angle mapper (SAM) were used to map the distribution of hydrothermally altered rocks associated with the porphyry copper mineralization. The band ratio combination of both sensors for mapping altered areas showed similar outcomes. PCA exposed variations in the spatial distribution of hydroxyl‐bearing minerals. The representation of hydrothermal areas using OLI data was more satisfactory than when using ETM+ data. SAM analysis found similar results for mapping hydroxyl‐bearing zones. Verification of the results came through ground investigation and laboratory studies. Rock samples (n = 56) were collected to validate results using thin sections, X‐ray diffraction (XRD) and spectral analyses. Field observations and laboratory analysis revealed that phyllic and propylitic alterations dominate the alteration zones in the study area. Argillic and iron oxides/hydroxides alterations were observed to a lesser degree. The results indicate that alteration maps prepared by OLI data using PCA for visual interpretation are more suitable than those of ETM+ due to a higher radiometric resolution and lower interference between vegetation and altered areas. As the spectral bandwidth of ETM+ band 7 covers absorption feature of propylitic alteration, better mapping of propylitic alterations is achieved using ETM+ data. 相似文献
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Eastern Iran has great potential for the discovery of different types of mineralization. The study area encompasses Tertiary magmatism in the northern Lut block located in northern Khur, South Khorasan, eastern Iran and is mostly covered by volcanic rocks, which are intruded by porphyritic subvolcanic intrusions in some places. Application of the spectral angle mapper (SAM) technique to Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) images detected sericitic, argillic, and propylitic alterations, silicification, and secondary iron oxides. The alteration is linear and associated within vein-type mineralization. Twelve prospective areas are selected for detailed exploration and based on our processing results, in addition to NW-SE faults, which are associated with Cu mineralization indications, NE-SW faults are also shown to be important. Based on the presence of subvolcanic rocks and numerous Cu ± Pb-Zn vein-type mineralizations, extensive alteration, high anomaly of Cu and Zn (up to 100 ppm), the age (43.6 to 31.4 Ma) and the initial 87Sr/86Sr ratio (0.7047 to 0.7065) of the igneous rocks, and the metallogenic epoch of the Lut block (middle Eocene-lower Oligocene) for the formation of porphyry Cu and epithermal deposits, the studied area shows great potential for porphyry copper deposits. 相似文献
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以ASTER遥感影像为数据源，对青海祁漫塔格成矿带虎头崖矿区，应用成像光谱法和主成分分析法对矿区矿化蚀变异常信息进行提取分析。成像光谱方法利用最小噪音分量（MNF）变换、像元纯度指数（PPI），n维可视化（n-Dimensional Visualization）端元识别，并进行混合谐调匹配滤波（MTMF），最终得到矿区的矿物信息分布图。而主成分分析法则选择ASTER1、2、3、4波段提取铁染异常信息，1、3、4、5波段提取矽卡岩化蚀变异常信息，1、3、4、（5+6）/2波段提取蒙脱石、伊利石与绢云母等矿物的蚀变异常信息，1、3、4、8波段提取方解石、黑云母、绿泥石等矿物的蚀变异常信息。利用野外实地踏勘确定的矿床、矿（化）点，在ArcGIS10.1软件中对遥感提取蚀变异常信息进行验证显示，二者吻合效果良好，表明提取结果与数据处理方法较可靠，对于扩大找矿规模和发现矿化富集地段具有重要的指导意义。 相似文献
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In recent years, the Neoproterozoic Huqf Supergroup formations of the Oman Salt Basins have been the target for oil exploration. The present study maps the surficial exposure of the Huqf Supergroup in and around Khufai Dome of the Huqf area in the Sultanate of Oman using low-cost multi-spectral remotely sensed satellite data and image processing methods such as decorrelation stretching, principal component analysis (PCA) and spectral angle mapper (SAM), as alternative to expensive and time-consuming tools, which have the capability and potential to be used by geoscientists for oil exploration. In this research, the study of Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) spectral bands 8, 3 and 1 by decorrelation stretching well discriminated the Masirah Bay, the Khufai, the Shuram and the Buah Formations of the Nafun Group, the source rocks of Huqf Supergroup with the Quaternary deposits. The analysis of visible and near infrared–shortwave infrared spectral bands of ASTER by PCA clearly showed the occurrence and spatial distribution of such formations in the RGB principal component images (R:PC1, G:PC2, B:PC3). The spatial distributions of such formations are assessed by confusion matrix after using maximum likelihood (ML), spectral angle mapper (SAM) and spectral information divergence (SID) algorithms. The matrix of ML algorithm has provided the best overall accuracy of 92.93% and kappa coefficient of 0.92. The minerals of the formations were detected by SAM. Further, the detection of such mineral groups was confirmed through the ASTER thermal infrared (TIR) spectral indices image developed using the carbonate index (CI), quartz index (QI), and mafic index (MI). All results of image analyses are evaluated in the field and laboratory studies. The study also evaluates the satellite data and image processing methods for the formations of Jabal Akhdar, the equivalent formations of the Khufai Dome, to show the sensor capability and the use of the image processing methods to study the source rocks. The results of the study provided similar discriminations comparable to the Khufai Dome. Therefore, the data and the techniques are recommended to the exploration geologists for use in similar regions of the world. 相似文献
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玉龙斑岩铜矿晚期绢云母化、黏土化蚀变强烈叠加在早期的钾硅酸盐化带内,模糊了蚀变分带特征及其与铜矿化之间的相关性.利用短波红外光谱(SWIR)可快速识别斑岩铜矿床内含羟基蚀变矿物,根据该类矿物的空间分布特征与矿化的对应关系,指导找矿勘查工作.本文对玉龙铜矿床靠近斑岩体中心的三个钻孔进行了详细的蚀变-矿化编录和SWIR分析... 相似文献
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Oktay Canbaz Önder Gürsoy Ahmet Gökce 《Journal of the Geological Society of India》2018,91(4):483-488
Remote sensing technology and its terrestrial components are more useful than classical geological investigation in mineral exploration and mapping the hydrothermal alteration areas and help to investigate larger areas in short time. Intrusive and volcanic rocks, namely Kösedag syenite and Karatas volcanics in Kösedag (Zara) area shows argillic alteration zones. Two different test area were chosen and sampled for mineralogical studies. XRD-CF investigations showed that kaolinite and illite are the dominant clay minerals in test areas of A and B respectively. The spectroradiometer measurements were carried out 5 times on different surfaces of clayey samples with self-illuminated contact-probe lens within the wavelength range of 350-2500 nm. The spectroradiometer measurements used as endmember were resampled to ASTER short wave infrared (SWIR) bandwidths. Band ratio, principal component and decorrelation stretching analysis were performed to visualize the distribution of clay minerals. In spectral classification method, matched filtering (MF) was used for integrating the satellite image and spectroradiometer measurement data. It was concluded that co-interpretations of the band ratio, principal component, decorrelation stretching analysis, MF results and geological map are very useful in determining, classifying and mapping of the argillic alteration zones related to hydrothermal processes on ASTER image and they seem to be very useful to identify the target areas for mineral exploration. 相似文献
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This study presents classifications of Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) imagery based on spectral analysis of alteration minerals associated with gold mineralization in Abo Marawat area which is located in the Central Eastern Desert of Egypt. Spectral analysis of continuum removed reference spectra of alteration minerals alunite, kaolinite, sericite, and calcite from USGS and JPL spectral libraries show shifts in position, shape, and strength most probably related to changes in sample purity and particle size of analyzed samples. Spectral Information Divergence (SID) classification method proved successful for mapping sericite, calcite, and clay minerals. Spectral Angle Mapper (SAM) classification identified only sericite and calcite alteration minerals. The identified alteration zones are coincidence with the field sampling and geological map of the study area. The microscopic examination of samples collected from the quartz veins and hydrothermally altered wall-rocks from near surface and subsurface at Abu Marawat gold mine shows sericitization, argillaceous, and carbonatization alteration zones. Gold occurs as very fine inclusions in pyrite, chalcopyrite, and sphalerite and also found filling the fractures between chalcopyrite grains. This study concludes that ASTER image classifications using reference spectra are a stable and reproducible technique for mapping gold related hydrothermal alteration zones in areas with no dominant vegetation cover. 相似文献
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近年来红外光谱技术作为一种绿色、快速、无损、精确探测矿物的技术手段而倍受关注,针对斑岩型矿床蚀变矿物高度叠加、蚀变分带界线不明显、细粒蚀变矿物多、黏土蚀变矿物多等特征,该技术在蚀变矿物识别和勘探信息解读等方面优势突出。本文应用红外光谱技术对云南普朗斑岩铜矿区钻孔ZK1801岩心进行矿物识别和蚀变分带划分的研究,识别出钾硅酸盐化带、绿帘石-绿泥石化带、绿泥石-伊利石化带、石英-伊利石化带和泥化带。研究表明:普朗铜矿整个钻孔的蚀变矿物主要有石英、钾长石、绢云母、绿泥石、绿帘石、高岭石、蒙脱石、伊利石等;根据矿化特征,发现铜矿体广泛赋存在钾硅酸盐化带和绿帘石-绿泥石化带中,与矿化关系密切的蚀变矿物"石英+钾长石+绢云母"和"绿帘石+绿泥石",可以作为普朗矿床勘查的标型蚀变矿物组合;研究区广泛发育的绢云母Al—OH波长随钻孔深度增加而逐渐从2210～2205nm减小到2202～2198nm, Al—OH波长2210～2205nm(长波绢云母)与矿化关系密切,可以作为普朗矿床勘查的指示信息。 相似文献
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Visible near infrared and shortwave infrared (VNIR-SWIR, 350 to 2500 nm) reflectance spectra obtained from an analytical spectral device (ASD) have been used to define alteration zones adjacent to porphyry copper deposits (PCDs), in the central part of Kerman magmatic arc, SE Iran. The spectral analysis identified sericite, illite, halloysite, montmorillonite, dickite, kaolinite, pyrophyllite, biotite, chlorite, epidote, calcite, jarosite, and iron oxyhydroxides (e.g. hematite, goethite) of hydrothermal and supergene origin. Identified alteration zones are classified into six principal types namely phyllic, phyllic/propylitic, propylitic, potassic, argillic and advanced argillic. The iron oxide minerals in the oxidized zone were also identified using spectral analysis. Results of spectral analyses of samples are consistent with mineralogical data obtained from X-ray diffraction (XRD) and petrographic studies. Spectroscopic studies by ASD demonstrate that this tool is very useful for semi-quantitative and cost effective identification of different types of alteration mineral assemblages. Furthermore, it can provide a valuable tool for evaluating aerial distribution of alteration minerals while coupled with remote sensing data analysis. 相似文献
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The Cenozoic Urumieh–Dokhtar Magmatic Belt (UDMB) of Iran is a major host to porphyry Cu ± Mo ± Au deposits (PCDs). Most known PCDs in the UDMB occur in the southern section of the belt, also known as the Kerman Copper Belt (KCB). Three major clusters of PCDs are distinguished in the KCB and include the Miduk, Sarcheshmeh and Daraloo clusters. The Daraloo and Sarmeshk deposits occur in a northwest–southeast-trending fault zone that is characterized by the presence of a narrow zone of alteration–mineralization that contains a series of Oligocene granitoids and Miocene porphyritic tonalite–granodiorite plutons that cut Eocene andesitic lava flows and pyroclastic rocks. Here we use various techniques, including different ratio images, minimum noise fraction, pixel purity index, and matched filter processing to process ASTER data (14 bands) and generate maps that portray the distribution of hydrothermal minerals (e.g., sericite, kaolinite, chlorite, epidote and carbonate) related to PCD alteration zones. In order to validate the ASTER data, follow-up ground proofing and related mineralogical work was done which, in all cases, proved to be positive. The results of this work have identified the regional distribution of hypogene alteration zones (i.e., phyllic, argillic, propylitic and silicic), in addition to areas of secondary Fe-oxide formation, which are coincident with known sites of PCDs. The regional distribution and extent of the alteration zones identified also highlighted the role of regional structures in focusing the mineralizing/altering fluids. These results demonstrate very convincingly that ASTER imagery that uses the appropriate techniques is reliable and robust in mapping out the extent of hydrothermal alteration and lithological units, and can be used for targeting hydrothermal ore deposits, particularly porphyry copper deposits where the alteration footprint is sizeable. 相似文献
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利用ASTER提取德兴斑岩铜矿遥感蚀变分带信息 总被引：7，自引：1，他引：6
在遥感光谱分析的基础上,结合德兴斑岩铜矿矿床地质特征,利用ASTER遥感数据提取了德兴斑岩铜矿的遥感蚀变分带信息.德兴斑岩铜矿蚀变分带根据蚀变矿物特征来分析,主要的蚀变矿物为白云母、伊利石、绿泥石、方解石、白云石;根据光谱特征,采用比值、斜率、相关吸收和主成分分析4种提取方法提取各蚀变矿物的信息,并采用叠加法对各蚀变矿物信息进行叠加,从而形成各个蚀变分带的遥感信息.各蚀变分带的遥感信息总体特征比较明显.最后,根据矿床成矿模式对蚀变分带信息进行了分析. 相似文献
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This study demonstrates the capability of the longer wavelength (L-band) and fine mode images of the Phased Array type L-band Synthetic Aperture Radar (PALSAR), and the optical spectral bands of the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) to map sedimentary formations and structures of the Marmul region, Central Oman. Results of study shows that the principal components image of the visible and near infrared–shortwave infrared (VNIR-SWIR) spectral bands of the ASTER have potential to discriminate the occurrence and distribution of marine and Quaternary sedimentary formations of the region. The color composite image developed using PALSAR data (R:HH?+?HV; G:HH; B:HV) has capable to differentiate the occurrence of the sedimentary formations and structures of the region. We developed ratios images by summing the HH intensity as a numerator and the HV intensity as a denominator (R:HH+(HH?+?HV)/HV, G:HH?+?HV, B:HH/HV), and by summing the HV intensity as a numerator and the HH intensity as a denominator (R:HV+(HH?+?HV)/HH, G:HV?+?HH, B:HV/HH) to study better the sedimentary formations and structures. The images discriminated well the occurrence of the limestones and shale formations of the marine deposits, the wadi alluvium of the Quaternary deposits and the manmade building structures of the region. We studied the minerals of the sedimentary formations using VNIR-SWIR spectral bands of the ASTER by spectral angle mapper (SAM) image processing method. The study showed presence of carbonates, silicates and OH bearing aluminosilicate minerals in the formations. The image interpretations are verified in the field and confirmed by the laboratory studies. 相似文献
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选取陕西省榆林气田地区为研究区, 利用ASTER数据多波段的优势, 在研究区开展了基于波段运算和主成分分析的二价铁、黏土矿化以及碳酸盐矿化等烃类微渗漏蚀变信息提取, 圈出4个有效靶区; 并利用ASTER数据的热红外波段进行基于分裂窗简化算法的温度反演得到研究区的温度图像以验证靶区的有效性, 温度反演结果中高温异常区和靶区范围基本吻合; 最后对USGS光谱库中常见蚀变矿物光谱、研究区实测光谱以及原油光谱进行综合分析, 进一步验证靶区有效性, 多种方法相结合以提高烃类微渗漏蚀变信息提取精度。 相似文献
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基于ASTER数据的内蒙古东乌珠穆沁北部地区遥感蚀变信息提取 总被引：1，自引：1，他引：0
ASTER数据在短波红外和热红外波段光谱信息明显优于ETM,使得在ASTER波段范围内能够更为详尽地刻画地物波谱,尤其是具有特征谱带的岩石和矿物.选择内蒙古东乌珠穆沁旗北部地区为工作区域,设计了用光谱角制图法提取矿化蚀变信息的技术方案.通过波段组合和增强处理,ASTER数据对含Fe-OH(如黄钾铁矾,含铁白云母)、Al-OH(如粘土类矿物、明矾石、绿泥石、绢云母)和Fe~(3+) (如褐铁矿,赤铁矿)3种类型蚀变信息的刻画能力明显比ETM更好.野外查证了提取结果的可靠性. 相似文献
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This study is an attempt to understand the application of spectral image processing methods to ASTER data for mapping host rock associated with porphyry copper-molybdenum mineralization. The application of remote sensing in identifying variations in surface mineralogy, structural elements, and lithologic contacts can help in identifying such relations. Signatures collected from the Advanced Spaceborne Thermal Emission Reflection Radiometer (ASTER) data is used to map the host rock of Zafarqand area. The study area is located in the central segment of the Urumieh–Dokhtar volcanic belt of Iran. The Urumieh-Dokhtar is a potential zone for exploration of new porphyry copper deposits. Band ratio, band math, false colour composites and principal component analysis techniques are used to refine the different lithologic units in the area. These methods showed the discrimination of acidic igneous rock from intermediate igneous rock and the boundary between igneous rocks using the shortwave infrared bands (SWIR) of ASTER at regional scale. Results have proven to be effective and in accordance with the results of field observations, ore microscopy examination and with reference geological map. In conclusion, the image processing methods used can provide cost-effective information to discover possible locations of porphyry copper and epithermal gold mineralization prior to detailed and costly ground investigations. The extraction of spectral information from ASTER data can produce comprehensive and accurate information for copper and gold resource investigations around the world, including those yet to be discovered. 相似文献
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德明顶矿区因交通不便、高寒缺氧、物理风化强烈、倒石堆覆盖严重等原因,找矿效果不理想.为进一步指导野外矿产勘查,在详细的野外观察的基础上,系统开展了短波红外光谱分析测试工作.结果显示,绢云母短波红外光谱标量在空间上呈现规律性变化,由浓集中心向外Al-OH吸收峰波长逐渐变长、Al-OH吸收峰深度逐渐降低、SWIR-IC值逐渐变小,且三者套合较好,表明该区域流体温度、压力高于外围,为热液蚀变矿化中心.结合蚀变规律、成矿岩体中锆石U-Pb年龄与辉钼矿Re-Os同位素年龄结果,在矿区内圈定了1处重点勘查靶区,为晚期铜矿化与早期（铜）钼矿化叠加的区域.该技术可以有效地指导野外矿产评价、降低勘查成本,是中国西部特殊景观区找矿勘查评价的重要方法之一. 相似文献
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多光谱遥感技术预测矿产资源的潜能——以蒙古国欧玉陶勒盖铜金矿床为例 总被引：9，自引：0，他引：9
建议把蚀变遥感异常作为一个新的找矿参数,文中讨论了蚀变遥感异常的地质基础和光谱前提。在矿床地质学和蚀变矿物光谱参数特征的基础上,编制了一张用于蚀变遥感异常提取及对其地质解释的表格。设计了从ETM+和ASTER数据中提取羟基蚀变矿物组合信息的独特流程方案。这个方案称之为"去干扰异常主分量门限化技术",文中示以简化的流程图。ETM+数据用来研究位于欧玉陶勒盖铜金矿床东北部的汉保各德中酸性火成杂岩体岩性特征,ASTER近红外和短波红外数据用来提取欧玉陶勒盖斑岩铜金矿矿床及其近区的羟基异常,通过选择性主分量分析判断欧玉陶勒盖铜金矿矿床的矿床类型为斑岩型。已知矿区各矿体的羟基异常都十分清晰,此外在矿床西部还发现了三个新的有希望的羟基异常。此工作进一步展示出多光谱遥感技术对于金属矿床的预测具有极好的潜能。 相似文献